Meetings: Documents

Documents: 1055
Sort          
Presented at the 2018 AGU Fall Meeting
Hu, R., Lin, X., and Yu, L. (13-Dec-18). Measurements from the Soil Moisture Active Passive (SMAP) and Optimum Interpolation Sea Surface Temperature (OISST) acquired during 2016 to 2017 in the Kuroshio-Oyashio Extension Region (KOER) and Gulf Stream (GS) are used to reveal the sea surface salinity (SSS) and temperature (SST) structure of the mesoscale eddies with an unprecedented space and time resolution.
Soloviev, A. and Dean, C. (17-Apr-15). Convective rains in the Intertropical Convergence Zone (ITCZ) produce lenses of freshened water on the ocean surface. These lenses are localized in space and typically involve both salinity and temperature anomalies. Due to significant density anomalies, strong pressure gradients develop, which result in lateral spreading of freshwater lenses in a form resembling gravity currents.
Bruscantini, C.A., Grings, F., Barber, M., Perna, P., and Karszenbaum, H. (10-Sep-15). Several retrieval algorithms were implemented to retrieve soil moisture and optical depth from Aquarius/SAC-D satellites. The methodology of a novel Bayesian algorithm is presented, and its results are contrasted with previous algorithms.
Bruscantini, C.A., Grings, F., Barber, M., Perna, P., and Karszenbaum, H. (12-Nov-13). Several retrieval algorithms were developed to retrieve soil moisture (SM) from passive remote sensing data. The most commonly used are the Single Channel Algorithm (SCA), the Dual Channel Algorithm (DCA) and LPRM. In this paper, a novel retrieval algorithm (BRA, Bayesian Retrieval Algorithm) is developed, which uses Bayesian inference to retrieve SM and optical depth from both H & V channels.
Manaster, A., Meissner, T., and Wentz., F. (27-Aug-18). The most recent versions of SMAP L-Band radiometer salinity retrievals are the Jet Propulsion Lab Version 4 (JPL V4) and the Remote Sensing Systems Version 3 (RSS V3) L2 and L3 salinity data. These two products represent the latest round of improvements to SMAP salinity measurements. In this study JPL V4 and RSS V3 salinities are compared at various spatial and temporal scales and differences between the two are examined. By cataloging the similarities and differences between the two products, we can further work towards even more accurate and convergent SMAP salinity retrievals.
Schanze, J.J. and Lagerloef, G. (18-Nov-15). With the recent advent of remotely sensed sea-surface salinity (SSS) data, it has become possible to compute sea surface density by combining SSS with remotely sensed sea surface temperature (SST) data. The International Thermodynamic Equation of Seawater 2010 (TEOS-2010) is used with Aquarius SSS and the Aquarius ancillary SST product to compute sea surface density (SSD).
Schanze, J. and Lagerloef, G. (26-Feb-16). With the recent advent of remotely sensed sea-surface salinity (SSS) data from missions such as Aquarius/SAC-D and Soil Moisture and Ocean Salinity (SMOS), it has become possible to compute sea surface density from these data in conjunction with existing remotely sensed sea surface temperature (SST) data. The International Thermodynamic Equation of Seawater - 2010 (TEOS-2010) is used with Aquarius SSS and the Aquarius ancillary SST product to compute sea surface density.
Misra, S. and Brown, S. (13-Nov-14). The following talk will present an instrument-only calibration algorithm that does not use the ocean salinity model for calibration correction. The talk is divided into three portions. The first part will discuss the potential root-cause for the offset and gain drifts observed. The second portion of the talk details the wiggle correction algorithm applied. The last portion of the talk will discuss the drift correction algorithm.
deCharon, A. and Rabolli, M. (17-Nov-15). Throughout the life of Aquarius/SAC-D, NASA and CONAE have worked closely together to share the excitement, findings, and societal importance of the mission. Their individual and collective efforts have reached thousands of people, including teachers who have been trained to include topics related to the mission's science, technology, engineering, and mathematics (STEM) in their classrooms.
Drushka, K., Asher, B., Thompson, E.J., Iyer, S., Jessup, A.T., and Clark, D. (12-Feb-18). A major objective of the SPURS-2 project is to understand the processes by which the patchy, shallow layers of fresher water created by rainfall on the ocean surface are transformed into the observed large-scale ocean salinity structures. Here, we focus on the specific question of the role played by turbulence in the upper meter of the ocean in mixing rain-induced fresh lenses.
Rosenberg, A.M., Edson, J.B., Farrar, J.T., and Plueddemann, A.J. (26-Feb-14). The Weather Research and Forecasting Model is used to investigate the nature of moisture fluxes and precipitation during the NASA Salinity Processes in the Upper-Ocean Regional Study (SPURS).
Jones, L., Hejazin, Y., and Jones, L. (13-Nov-14). In this poster, a microwave radiometer derived sea surface roughness correction algorithm is presented that uses a new semi-empirical microwave Radiative Transfer Model (RTM) to estimate the excess ocean emissivity using ancillary data such as sea surface temperature (SST) and ocean surface wind vector.
Khodri, M., Friedman, A.R., and Reverdin, G.P. (25-Feb-16). We present a new record of observed sea surface salinity (SSS) data, which has been compiled and processed to provide improved spatial coverage for the period 1896-2013. We discuss the characteristics of this data set and how we group the data in time series in 23 sub-regions from 20°S to 70°N, away from shelves.
Kilic, L., Prigent, C., Aires, F., Boutin, J., Heygster, G., and Meissner, T. (29-Aug-18). Surface characterization from satellites is required to understand, monitor and predict the general circulation of the ocean and atmosphere, the interaction between the surface and the atmosphere, as well as the water and energy cycles. With more than 70% cloud coverage at any time, visible and infrared satellite observations only provide limited information. Regardless of the cloud cover, passive microwaves offer ocean and sea ice information such as Sea Surface Temperature (SST), Ocean Wind Speed (OWS) even under extreme conditions, Sea Surface Salinity (SSS), Sea Ice Concentration (SIC) or thin Sea Ice Thickness (SIT). These products are particularly important for polar regions that are very vulnerable to climate change. Up to now all these oceanic/sea ice parameters estimated from passive microwave observations are limited in spatial resolution and/or accuracy.
Presented at the 2018 AGU Fall Meeting
Misra, S., Ramos, I., Felten, C., Bosch-Lluis, J., Brown, S.T., Yueh, S.H., Latham, B., and Lee, T. (14-Dec-18). NASA's Aquarius and SMAP (Soil Moisture Active Passive) missions operating at 1.4 GHz (L-band) successfully demonstrated the ability to measure sea-surface salinity (SSS) at a high precision. Though successful, a narrow band-width of 24 MHz on both of the passive sensors limited retrievals of sea-surface salinity to global regions with warmer sea-surface temperatures, due to reduced SSS sensitivity at L-band at lower sea surface temperatures (SST). A narrow bandwidth also requires external ancillary wind speed (WS) and sea surface temperature (SST) data to inform the retrieval algorithms.
Bruscantini, C.A., Grings, F.M., Barber, M., Franco, M., Entekhabi, D., and Karszenbaum, H. (31-July-15). A novel downscaling methodology for intermediate spatial resolution radiometer data is developed in view of forthcoming SMAP mission. It is based on an active and a passive microwave forward model coupled by its ancillary parameters.
Chen, D.D. and Ruf, C. (09-Sep-15). Microwave radiometer RFI detection methods has a big challenge of evaluating the ground truth of the RFI environment. A method is introduced to observe the probability distribution of RFI amplitude around the globe, to characterize the RFI environment. The method is presented, followed by future improvements.
Palma, E.D., Matano, R.P., and Nof, D. (12-Nov-13). In this presentation we use Aquarius data and the results of a suite of process-oriented numerical experiments to investigate the dynamical mechanisms controlling the spreading of the Amazon and Congo plumes.
Farrar, J.T., Plueddemann, A.J., Kessler, W.S., Rainville, L., and Hodges, B.A. (27-Feb-14). The SPURS measurement program included a heavily instrumented air-sea interaction mooring, which allows accurate estimates of the surface fluxes, and a dense array of measurements from moorings, Argo floats, and gliders. Here we report preliminary air-sea flux estimates and the evolution of upper ocean heat and freshwater content from the air-sea interaction mooring.
Lan, H., Zhao, T., Zhang, Z., and Shi, J. (09-Sep-15). The Aquarius mission's goal is to provide sea surface salinity. It is a collaboration between NASA and Argentina's space agency. This paper will be assessing the RFI contamination that is present over China, that are mainly caused by the cities' air-traffic control radars.
Santos-Garcia, A., Aslebagh, S., Jacob, M.M., and Jones, W.L. (26-Feb-14). This paper presents results of the Aquarius Cal/Val effort to improve the Sea Surface Salinity measurements during and/or after significant rainfall events. In this regard, we have developed the AQ Rain Accumulation Product, which provides a time-history of rainfall averaged over an AQ IFOV.
Jones, W.L., Hejazin, Y., and El-Nimri, S. (12-Nov-13). This poster presents an alternative independent approach for the AQ roughness correction, which is derived using simultaneous measurements from the CONAE Microwave Radiometer (MWR).
Hejazin, Y., Jones, W.L., and El-Nimri, S. (10-Sep-15). The Aquarius/SAC-D mission science objective is to provide high-resolution global sea surface salinity (SSS) maps every 7-days, which are derived using the AQ combined L-band radiometer/scatterometer. In this paper, an alternative sea surface roughness correction algorithm is presented that uses a new semi-empirical Radiative Transfer Model (RTM) to estimate the ocean emissivity.
Jacob, M.M., Jones, L., Drushka, K., and Asher, W. (28-Aug-18). When rain falls over the ocean, it produces a vertical salinity profile that is fresher at the surface. This fresh water will be mixed downward by turbulent diffusion through gravity waves and the wind stress (Boutin et. al., 2014), which dissipates over a few hours until the upper layer (1-5 m depth) becomes well mixed. Therefore, there will be a transient bias between the bulk salinity, measured by in situ instruments, and the satellite-measured SSS (representative of the first cm of the ocean depth).
Jacob, M.M., Jones, W.L., Drushka, K., and Scavuzzo, M. (12-Feb-18). When rain falls over the ocean, it produces a vertical salinity profile that is fresher at the surface. This fresh water will be mixed downward by turbulent diffusion through gravity waves and the wind stress, which dissipates over a few hours until the upper layer (1-5 m depth) becomes well mixed. Therefore, there will be a transient bias between the bulk salinity, measured by in-situ instruments, and the satellite-measured SSS (representative of the first cm of the ocean depth).
Jacob, M., Jones, L., Drushka, K., Asher, W., and Scavuzzo, M. (20-Sep-17). This poster presents a demonstration of the Rain Impact Model (RIM) for SMAP, SMOS and Aquarius, under a variety of conditions. The RIM-predicted salinity is found to agree with satellite-derived surface salinity. RIM can also provide a robust quality flag to identify areas of salinity stratification.
Shukla, R.K., Shaji, C., Ojha, S.P., Kumar, P. (25-Apr-17). The upwelling in Arabian Sea is an important phenomenon, mainly occurring along the southwest coast of India during summer monsoon, which increases the biological productivity in the region. The south west coast of Arabian sea region accounts for about 53% of fish yield of the total fish production in Arabian Sea, thus it is imperative to study and understand the process of upwelling in this region. To study the upwelling features in southwest coast of India, monthly Ekman mass transport is estimated using analyzed wind and derived products from Oceansat-II scatterometer data. Seasonal variability of Ekman mass transport has been analyzed to study the occurrences of coastal upwelling in this region. Results show prominent region of upwelling along southwest coast of India is between 7° and 15° N.
D'Addezio, J.M. and Bingham, F.M. (26-Feb-14). The subtropical surface salinity maximum region of the North Atlantic Ocean is a complex feature created by air-sea interactions and while the SPURS (Salinity Processes in the Upper Ocean Regional Study) research group has extensively studied how the ocean itself creates this feature, less is known about how the atmosphere above the region is driving it.
Presented at the 2014 AGU Fall Meeting
Bingham, F. and D'Addezio, J. (18-Dec-14). The synergistic effects of evaporation (E), precipitation (P), and Ekman transport make the SPURS (Salinity Processes in the Upper Ocean Regional Study) region in the subtropical North Atlantic (15-30°N, 30-45°W) the ideal location for the world's highest open ocean sea surface salinity. Using the MERRA and ERA-Interim atmospheric reanalyses, we reproduce the mean hydrologic state of the atmosphere over the SPURS region since 1979 and roughly deduce the change in salinity across the meridional domain due solely to interactions between E-P and Ekman transport.
Presented at the 2016 AGU Fall Meeting
Fournier, S., Reager, J.T., Lee, T., Vazquez, J., David, C.H., Gierach, M.M. (16-Dec-16). Floods are natural hazards that can have damaging impacts not only on affected land areas but also on the adjacent coastal waters. NASA’s Soil Moisture Active Passive (SMAP) mission provides measurements of both surface soil moisture and sea surface salinity (SSS), offering the opportunity to study the effects of flooding events on both terrestrial and marine environments. Here, we present analysis of a severe flood that occurred in May 2015 in Texas using SMAP observations and ancillary satellite and in situ data that describe the precipitation intensity, the evolving saturation state of the land surface, the flood discharge peak, and the resulting freshwater plume in the Gulf of Mexico.
Kerr, Y.H. and Lambin, J. (06-Nov-18). This presentation outlines the history, current state, and funding of ocean-observing satellite missions supported by the Centre National d'Édudes Spatiales (CNES). CNES missions include SMOS (Soil Moisture and Ocean Salinity), launched in 2009; current operations have been extended to 2019 and beyond. CFOSAT (China-France Oceanography SATellite, a joint mission of CNES and the China National Space Administrate, launched in October 2018), and two potential missions (SMOS-HR and CIMR) are discussed along with programmatic details (potential partnering, funding, an L-band radiometer long-term program, and lobbying efforts).
Abe, H. and Ebuchi, N. (11-Nov-14). The present study examined ocean salinity responses tothea passage of a typhoon using Aquarius Level-2 swath sea surface salinity (SSS) data and Level-3 weekly-averaged SSS data. We targeted one typhoon generated in the east of the Philippines in 2012; after the formation, it moved to the north-east direction by crossing the western North Pacific basin, then passed through the south of Japan, and on into the central North Pacific. Analyses of the Aquarius data were conducted by focusing on a region near Japan.
Hacker, P. and Melnichenko, O. (17-Oct-17). A review of Aquarius Sea Surface Salinity achievements for ocean sciences, separated by topic area.
Guerrinero, L., Ferrazzoli, P., Vittucci, C., Aurizzi, M., and Vergata, T. (11-Apr-16). In the last decades, researches based on passive and active systems were mostly conducted separately. More recently, a joint use of the two techniques were investigated with the objective of exploiting both the good properties of SAR in terms of high resolution and the good sensitivity of radiometric observations to soil moisture. Signatures collected by Aquarius instrument mounted on the SAC-D satellite, although dedicated to ocean applications, are also used to investigate a joint use of active and passive L band observations over land, particularly in large homogeneous areas (Piles et al., TGRS, pp. 4700-4711, 2015).
Rainville, L., Shilling, G., et al. (07-Nov-18). In SPURS-2, the use of autonomous platforms enabled the capture of many different events (persistence), which is essential to link the different scales important for the water cycle. Seagliders were used to adaptively sample rainfall events, using satellite and local information for deployment. In addition to measuring the water column, gliders are equipped with a passive acoustic sensor to provide direct estimates of in situ rain rate and wind speed.
Rainville, L. and Shilling, G. (20-Sep-17). Various platforms for observing freshwater anomalies, precipitation and rain events are evaluated in this poster, including sea gliders and acoustic rain sensors. Selective and adaptive sampling is possible by combining autonomous gliders and remote sensing.
Colliander, A., Chae, C.S., Kainulainen, J., Dinnat, E., Torres, F., Corbella, I., Oliva, R., and Martin-Neira, M. (10-Sep-15). Over the course of the more than four-year mission several enhancements have been developed for the calibration of the zero-baseline radiometers of ESA's SMOS (Soil Moisture Ocean Salinity) mission.
Barraza, V., Grings, F., Ferrazzoli, P., Huete, A., Restrepo-Coupe, N., and Karszenbaum, H. (12-Nov-13). This study analyzes time series of passive microwave data collected in Southern Hemisphere ecosystems of Australia and Argentina.
Brown, S. (18-Jan-17). An update on air-sea temperature dependence – which has been hypothesized to be the cause of seasonal biases observed at high latitudes in Aquarius data, – is provided. Version 4.5 (V4.5) data have been analyzed to see if the air-sea dependence observed in Version 4.2 and earlier products was an artifact of the O2 absorption model. Measured versus expected antenna temperature (TA) and winds are compared with air-sea temperature differences (dT) for vertically- and horizontally-polarized data. Results indicate that air-sea temperature difference dependence could be incorporated into Aquarius emissivity corrections (model function) or as a look-up table for delta impacts.
Sabia, R., Klockmann, M., Fernandez-Prieto, D., and Donlon, C. (17-Apr-15). Recent work linking satellite-based measurements of sea surface salinity (SSS) and sea surface temperature (SST) with traditional physical oceanography has demonstrated the capability of generating routinely satellite-derived surface T-S diagrams and analyze the distribution/dynamics of SSS and its relative surface density with response to in-situ measurements. Even more recently, this framework has been extended by exploiting these T-S diagrams as a diagnostic tool to derive water masses formation rates and areas.
Jiang, Y. (28-Aug-18). The Amazon river discharges about 15% of all the fresh water into the oceans by all the rivers of the world. Seasonal fresh water discharge from Amazon river is shown by the lower sea surface salinity (SSS) plume in the Atlantic Ocean. Both RSS SMAP SS v2.0 Level 3 dataset and Tropical Rainfall Measuring Mission (TRMM) Precipitation dataset spanning from 2015 to current are used for the analysis and comparison. SSS average from 55°W to 45°W in longitude and from 2°S to 10°N latitude region presents the seasonal variation with lowest SSS around summer and maximum around winter season which is lagged by about three months from the TRMM precipitation average data.
Tauro, C.B., Hejazin, Y., Jacob, M.M., and Jones, L. (17-Nov-15). The CONAE MWR team in collaboration with CFRSL has developed an improved algorithm for retrieving ocean wind speeds using the newest MWR V7.0 brightness temperature data.
Santos-Garcia, A., Aslebagh, S., Jacob, M.M., and Jones, L. (12-Nov-13). The purpose of this paper is to describe an AQ Rain Accumulation product and to present validation results using independent WindSat rain retrievals (EDR) that occur within ±45 minutes for ~60% of the AQ L2 science data pixels.
Asher, W., Drushka, K., Jacobs, M.M., and Jones, W.L. (28-Aug-18). Rain-induced freshening of the top meter of the ocean can cause an error in validating satellite salinity measurements with in situ salinity data measured at depths below the surface fresh layer. In order to determine the importance of this error, the Rain-Impact Model (RIM) was developed (Santos-Garcia et al., 2014). RIM is a semi-empirical model that estimates the rain-induced freshening between the surface and a depth of 1 m using global rain products and a one-dimensional model of vertical diffusion in the upper ocean.
Lee, T. (31-Mar-15). This presentation compares the Level 3 monthly Aquarius data with monthly maps of SSS based on Argo from APDRC, and provides a summary of biases, and statistics for their differences.
Xie P., Kumar, A., Xue, Y., and Liu, W.T. (17-Apr-15). Relationship between the sea surface salinity (SSS) and the oceanic fresh water flux (E-P) is examined using the SSS retrievals derived from the passive microwave (PMW) observations aboard the SMOS and Aquarius satellites, the CMORPH integrated satellite precipitation estimates (P) and the evaporation data (E) produced by the NCEP Climate Forecast System (CFS) reanalysis.
Camps, A., Park, H., and Gonzalez-Gambau, V. (10-Sep-15). Radio Frequency Interference is one of the most important limiting factors in the accuracy of the brightness temperatures. The L-band is affected by this, and a technique is presented as an attempt to mitigate the RFI at its origin.
Monk, S.A., Johnson, R.J., Bates, N.R., and Risi, C. (26-Feb-14). Variations in surface ocean salinity provide evidence of changing patterns in the global hydrological cycle, and the extensive time-series data collected at the Hydrostation S and Bermuda Atlantic Time-series Study (BATS) sites in the North Atlantic Ocean provides an excellent data source for investigating these changes.
Bruscantini, C.A., Grings, F.M., Perna, P., Karszenbaum, H., Crow, W.T., and Jacobo, J.C.A. (28-Sep-15). An Observing System Simulation Experiment for the Aquarius/SAC-D mission is being developed for assessing the accuracy of soil moisture retrieval from passive and active L-band remote sensing. The implementation of the OSSE is based on: a backscatter model and a forward microwave emission model to simulate the radiometer and scatterometer observations, a realistic orbital and sensor model to resample the measurements, and an inverse soil moisture retrieval model.
Perna, P., Bruscantini, C., Ferrazzoli, P., Grings, F., Karszenbaum, H., and Crow, W. (28-Sep-15). An Observing System Simulation Experiment (OSSE) for the Aquarius/SAC-D mission has been developed for assessing the accuracy of soil moisture retrieval. In this paper, OSSE attempts to capture the influence of this effect over estimated soil moisture.
Lagerloef, G. and Kao, H. (18-Nov-15). This study is a preliminary examination of multi-year sea surface salinity (SSS) trends from analyses of SMOS and Aquarius data, years 2010-2015 to assess the feasibility of monitoring such trends from satellite.
Hasson, A., Delcroix, T., Boutin, J., Hernandez, O., Martin, N., Alory, G., and Dussin, R. (17-Apr-13). The tropical Pacific Ocean has been in a La Niña phase from mid 2010 to early 2012. In this presentation, we will describe and analyze the well-marked signature of this ENSO phase, using a combination of in situ, SMOS- and model-derived sea surface salinity products.
Brown, S. (17-Jan-17). This presentation includes outputs of various analyses of Aquarius antenna temperature (TA) versus expected (TAexp) for vertical (V) and horizontal (H) polarizations. Deltas (d) between these are presented by month. In addition, monthly third Stokes (Q) maps and associated statistical data are included.
de Matthaeis, P., Soldo, Y., Le Vine, D.M. (10-July-16). Aquarius is an L-band active/passive sensor designed to globally map sea surface salinity from space. Two instruments, a radar scatterometer and a radiometer, observe the same surface footprint almost simultaneously. The radiometer is the primary instrument for sensing sea surface salinity (SSS), while the scatterometer is included to provide a correction for sea surface roughness, which is a primary source of error in the salinity retrieval.
Yang, J., Riser, S., and Asher, W. (24-May-17). In this talk, a preliminary analysis of the Argo and PAL data from the SPURS-2 deployment from Sep. 2016 – April 2017 are presented. In general, the PAL wind speed is consistent with wind speed measured by surface anemometers on the central mooring, while rainfall exhibits strong spatial variability. Salinity and temperature profiles from the 15 floats are presented as well to investigate their correlation with rainfall.
Anderson, J.E. and Riser, S. (12-Feb-18). During the first Salinity Processes in the Upper Ocean Regional Study (SPURS-1) a unique fleet of instrumentation was deployed in the approximate center of the evaporation dominated North Atlantic salinity maximum (~ 25°N, 38°W) to investigate the physical mechanisms controlling upper ocean salinity on a variety of space and time scales. Previous studies have shown that subsurface processes are as important as surface fluxes in maintaining the salinity maximum. In the present study, we examine the variability of mixed layer properties and subduction of high salinity water in the region during the one-year deployment period (October 2012-October 2013).
Piepmeier, J. (31-Oct-12). A briefing by the Antenna Temperature Calibration Working Group (TA-WG), including the findings investigating geophysical model errors, instrument errors and dynamic range.
Meissner, T. and Wentz, F. (29-Jan-13). Presentation gives an overview of the Aquarius antenna pattern correlation, the 3rd Stokes cross-polarization couplings, and 3rd Stokes calibration, including measured versus calculated during an S/C pitch maneuver.
Santos-Garcia, A., Jacob, M., Jones, L. and Asher, W. (11-Nov-14). This poster presents results of a recent empirical investigation into the impact of rain on the Aquarius (AQ) sea surface salinity measurements.
Santos-Garcia, A., Ebrahimi, H., Hejazin, Y., Jacob, M.M., Jones, L., and Asher, W.E. (10-Sep-15). This paper focuses on the effects produced by rainfall on the Aquarius sea surface salinity retrieval, using a macro-scale rain impact model.
Fore, A., Yueh, S., Tang, W. and Hayashi, A. (30-Mar-16). This presentation began with comparing data from Aquarius and SMAP (Soil Moisture Active Passive) versus WindSAT wind speed in terms of surface emissivity and geophysical model functions (GMF). Below wind speeds of 20 meters per second, there is generally good agreement between Aquarius and SMAP. Sea surface salinity (SSS) data from Aquarius and SMAP were then compared with Argo data and the HYCOM model. Brightness temperatures were computed and gridded to estimate wind speed and salinity using constrained objective function minimization. In summary, SMAP can continue the record of global SSS maps from space using L-band. SMAP's SSS accuracy is not as good as Aquarius but is close.
Gierach, M.M., Vazquez-Cuervo, J., Lee, T., and Tsontos, V.M. (13-Nov-13). Sea surface salinity (SSS) measurements from the Aquarius/SAC-D satellite and the SMOS mission are used to document the freshening associated with the record 2011 Mississippi River flooding event in the Gulf of Mexico (GoM).
Vazquez, J., Gierach, M.M, Lee, T., and Tsontos, V.M. (26-Feb-14). Sea surface salinity measurements from the Aquarius/SAC-D satellite and SMOS mission were used to document the freshening associated with the record 2011 Mississippi River flooding event in the Gulf of Mexico. Assessment of the salinity response was aided by additional satellite observations, including MODIS chlorophyll-a and ocean surface currents, and a passive tracer simulation.
Vinogradova, N.T., Ponte, R.M, Fukumori, I., and Wang, O. (13-Nov-13). Constraining dynamical systems with new information from ocean measurements, including observations of sea surface salinity (SSS) from Aquarius and SMOS, requires careful consideration of data errors that are used to determine ("weight") the importance of constraints in the optimization. Here such weights are computed as the reciprocal of the variance of data errors and are derived by comparing satellite SSS observations with ocean model output.
Piepmeier, J. (29-Jan-13). Findings include: initial calibration bias verified within pre-launch error bars; on-going instrument behavior exhibits exponentially decaying gain error ~0.5% (which has settled) and non-monotonic fluctuations ~0.1K, both of which are corrected in V2 products; and model exhibits errors of similar magnitude.
Piepmeier, J. (29-Jan-13). Findings include: there is a long-term gain drift well modeled by exponential decay; there are shorter-term non-monotonic offset errors (i.e., "the wiggles"); there remain modeling errors in the antenna temperature global average comparison; cold-sky and SMOS matchups over land indicate the full dynamic range calibration has too high a slope; and noise diode and APC coefficients are only consistent for ocean scenes.
Lee, T., Lagerloef, G.S.E., Gierach, M.M. Kao, H-Y., Yueh, S., and Dohan, K. (17-Apr-13). Sea surface salinity (SSS) measurements from Aquarius/SAC-D satellite provide the first satellite observations of the salinity structure of tropical instability waves in the Pacific and Atlantic Oceans. In the tropical Pacific, the associated SSS anomaly has a magnitude of approximately ±0.5 PSU.
Meissner, T., Wentz, F. and Lagerloef, G. (26-Mar-12). Ascending and descending biases were found to correlate with S3 and can largely be removed by adjusting x-pol coupling from S3 into Q. Residual ascending/descending biases do not appear to be persistent in time, strictly zonal, due to diurnal SST or diurnal ATM.
Yueh, S. (26-Mar-12). An introduction to the Aquarius Calibration and Validation workshop, including workshop goals and schedule.
Meissner, T. and Wentz, F. (27-Mar-12). A walk-through of the salinity retrieval algorithm for Version 1.3., including the differences between the current version and V1.1.
Brown, S. and Misra, S. (15-Nov-11). An analysis of several aspects of the radiometer calibration, including the linearity correction, reflector emissivity, 3rd Stokes calibration and gain and offset drift.
Brown, S. and Misra, S. (15-Nov-11). An analysis of several aspects of the radiometer calibration, including the linearity correction, reflector emissivity, 3rd Stokes calibration and gain and offset drift.
Aquarius Calibration Sub-Group (15-Nov-11). A summary report provided by the Aquarius Calibration Sub-Group.
Yueh, S. (11-Apr-12). Overview of Aquarius calibration/validation (cal/val) concludes: Aquarius instrument has been performing exceptionally well; on-orbit thermal control meets the design requirement; scatterometer calibration has been very stable; radiometer calibration meets the calibration requirement (0.13K within 7 days); there will be new science products (e.g., ocean surface wind, soil moisture, land surface freeze/thaw, etc.); Aquarius surface salinity accuracy has been rapidly improving; and there are some ongoing challenges for cal/val.
Dinnat, E. (29-Jan-13). Findings include: ocean calibration results in a few K cold bias at the low end of Ta's; temporal variation of cold Sky bias supports correction for large exponential drift at beginning of the mission; temporal variation of cold Sky bias & offset/wiggles is inconclusive; and there is a 1K uncertainty due to antenna pattern model.
Fore, A. (27-Mar-12). Results from Cross-Pol Calibration are presented. Faraday rotation correction seems to be improved when using the radiometer Faraday angle instead of model.
Xu, X. and Yueh, S. (28-Mar-12). Land data, binned to the SMAP grid map, was examined to determine whether freeze and thaw conditions could be detected. Maps of freeze/thaw conditions were produced.
Feldman, G.C., Gales, J., Hong, L., Kuring, N., Patt, F., Scott, A., and Wilding, J. (15-Nov-11). The Aquarius Ground System at NASA/GSFC consists of the Aquarius Data Processing System (ADPS) and the Aquarius Command and Control System (ACCS). This talk outlines the software development and distribution process, and the required documentation resulting from this process.
Feldman, G.C., Gales, J., Hong, L., Kuring, N., Patt, F., Scott, A., and Wilding, J. (15-Nov-11). The Aquarius Ground System at NASA/GSFC consists of the Aquarius Data Processing System (ADPS) and the Aquarius Command and Control System (ACCS). This talk outlines the software development and distribution process, and the required documentation resulting from this process.
Patt, F. (19-July-10). Presentation included information on: science data processing; Level-2 science software implementation; Level-2 data product format; data archive and distribution; Aquarius web site; and open issues (e.g., review and analysis of 2007 simulation products, agreement on ancillary data sets/sources and Level-2 parameters, etc.).
Patt, F. (29-Jan-13). Status of ground processing system and overview of L2 data products.
Lagerloef, G. and Kao, H-Y. (17-Apr-13). The Aquarius project released V2.0 data in February 2013. This was the first release to have an accompanying validation analysis based on in situ data, along with other supporting documents, whereas previous versions V1.X were for "evaluation" only.
Lagerloef, G. and Kao, H. (29-Jan-13). Findings include: global RMS error, for the entire 16-months together is ~0.46 psu; monthly mean RMS error is ~0.33 psu; significant annual error cycle and geographic error patterns, especially in southern hemisphere; ascending-descending annual cycle bias is mostly in the descending side of the orbit; and three-month average gridded fields global RMS error is ~0.27 psu.
Brown, S. and Misra, S. (26-Mar-12). This work uses on-earth calibration targets for stability tracking, namely Antarctica and a location in the rainforest. Antarctic and Rainforest trend estimates consistent with a gain drift in the Aquarius radiometer (e.g. noise diode). The next steps are to continue model development for both regions to increase fidelity as well as continue tracking the Aquarius performance.
deCharon, A. and Rabolli, M. (19-July-10). Overview includes: development of key messages and outreach "themes"; coordination of media opportunities; creation of EPO products; and engagement of scientists to broaden the impact of the mission's goals.
Mims, A. and Ruf, C. (28-Sep-15). This study addresses Aquarius' external calibration methods, using observed antenna temperatures to characterize instrument behavior by computing the oceanic global average and vicarious cold statistics.
Hong, L., El-Nimri, S., and Peng, J. (31-July-15). Aquarius is a space-borne 3-beam L-band microwave instrument with its radiometer measuring sea surface salinity and its scatterometer providing ocean roughness corrections for better retrieval. Since polarized signals are used in both salinity and surface wind retrievals, Faraday rotation correction is an important step in calculating both radiometer and scatterometer ocean surface signals.
Misra, S. and Brown, S. (18-Nov-15). The Aquarius instrument experience several different issues which can affect calibration, including drift, “wiggles” (i.e, pseudo-periodic oscillations in the data)and systematic psudo-random bias. The correction and status of all three issues are discussed within this presentation.
Melnichenko, O., Hacker, P., Maximenko, N., and Potemra, J. (16-Nov-11). Between 40-60 degrees south and 15-50 degrees north, there are large differences between beams. The noise in the records varies with latitude. A tentative conclusion from this analysis is that along-track calibration may be required for each beam seperately.
Meissner, T. and Wentz, F. (29-Jan-13). Findings include: excellent Aquarius wind speed retrievals with optimal channel configuration; in testbed, instantaneous wind speed measurement significantly improves roughness correction and correction for reflected galactic radiation; and significant performance improvement in salinity retrieval in testbed.
Hilburn, K., Scott, J., Meissner, T. and Wentz, F. (30-Jan-13). Overview of the following: status and description of Aquarius data set, including major changes/differences from Aquarius Data Processing System V2.0; microwave radiometer (MWR), including resampling methodology, absorption correction, and rain flagging; validation of sea surface salinity HYCOM model; and validation through a triple collocation error model using Aquarius and buoys.
Meissner, T., Hilburn, K., Wentz, F., and Scott, J. (16-Apr-13). The Aquarius L-band radiometer/scatterometer system is designed to provide monthly salinity maps at 150 km spatial scale to an accuracy of 0.2 psu. The sensor was launched on June 10, 2011, aboard the Argentine CONAE SAC-D spacecraft. The L-band radiometers and the scatterometer have been taking science data observations since August 25, 2011.
Misra, S. (17-Jan-17). This study has been conducted to ensure that Aquarius radiometers did not introduce long-term variation in salinity retrievals. Radiometer performance has been validated independent from the Hybrid Coordinate Ocean Model (HYCOM) using a ground-based source and double-difference methodology. Microwave emissions over Antarctica has proven to be an excellent relative calibration source at the frequency of Aquarius radiometers (L-band). The study concludes that all channel trends are within +/- 0.1 K over the life of the mission.
Brown, S. (31-Mar-15). An overview of the radiometer and its algorithm for detecting radio frequency interference (RFI), and a proposed approach for tuning parameters to reduce bias.
Lagerloef, G. and the Aquarius Cal/Val/Algorithm Team (12-Nov-13). Aquarius PI Gary Lageroloef summarizes mission status, data versions (1 through 4.0), and the science mission timeline. Click here for the Calendar Year 2012 Animation embedded on Page 2 of this presentation.
Lagerloef, G. (14-Nov-14). In this presentation, the author provides a broad overview of the statuts of the Aquarius mission, including an update on the latest data versions available, instrument health, and current mission status.
Lagerloef, G. (15-Apr-13). The nominal 3-year mission began 1 Dec 2011 and is scheduled to end 30 Nov 2014 (now almost half-way). An additional 3+ months data were obtained during the commissioning phase (25 Aug - 30 Nov 2011).
Lagerloef, G. (18-Nov-15). Soon after the SAC-D/Aquarius mission end in early June 2015, NASA directed the Aquarius project team to prepare a proposal for the Phase-F Mission Closeout plan. The plan calls for the decommissioning of the Aquarius Ground System, documentation, and final data archive. The science activity primarily involves a complete data reprocessing with numerous calibration and algorithm updates that had been planned for this year, in order to improve the accuracy and quality as far as we are able with our present knowledge and experience. This Aquarius Data Version 5.0 is scheduled to be released in early to mid 2017 and Phase-F activities will end 30 June 2017. This presentation will summarize the algorithm improvements and the schedule.
Lagerloef, G. (22-May-17). Conceived in the late 1990s, and proposed to NASA's Earth System Science Pathfinder (ESSP) Missions program in 2001-2002, the Aquarius mission was selected to resolve missing physical processes that link the water cycle, the climate, and the ocean by measuring sea surface salinity (SSS). The satellite was developed in partnership with Argentina as the joint Aquarius/SACD mission, and included complementary sensors provided by Argentina, Italy, France and Canada.
Scott, J. (28-Mar-12). Presented at the 2012 Aquarius Calibration/Validation Workshop in Santa Rosa, CA.
Yueh, S., Fore, A., Tang, W., and Hayashi, A. (18-Nov-15). Mounting evidence has suggested that ocean salinity may not be sufficient for being a surrogate rain gauge for monitoring the change of the ocean water cycle. The observed salinity signals are often formed as a result of oceanic processes instead of as a direct consequence of the freshwater flux changes at the ocean surface. One issue that needs to be considered is how we can minimize the influence of ocean dynamic processes and the other is what aspects of the ocean water cycle can be constrained or checked by ocean salinity.
Fore, A. (15-Nov-11). An assessment of the pointing error for aquarius is shown to be stable over time, to ~0.1 degrees. The pointing errors can be represented well by biases on the individual beams. Additionally, consistent results were found with both radar and radiometer data.
Yueh, S. (15-Nov-11). An overview of the objectives and logistics for the 2011 Calibration/Validation Workshop.
Feldman, G. (11-Apr-12). Presentation gives details of the transfer of Aquarius project management to the NASA Goddard Space Flight Center (GSFC) on Dec 1, 2011, to begin its "Operations" phase. An overview of the GSFC-operated Aquarius Ground System is also provided, along with status (e.g. V1.3 data products in the operational forward stream and viewable online, etc.).
Feldman, G., Gales, J., Hong, L., Kuring, N., Owens, T., Patt, F., Scott, A., and Wilding, J. (29-Jan-13). Summary of status includes: the Aquarius Ground Segment are working well, and there are no significant issues; the end-to-end process of Aquarius data collection has worked as designed since launch; and housekeeping Telemetry web-based analysis pages are widely used and have provided comprehensive, critical and timely information to help identify many issues that have arisen since launch.
Ruf, C. (20-July-10). Presentation includes a description of the Aquarius Radio Frequency Interference (RFI) flag algorithm, which is a "glitch detector" that identifies samples that deviate anomalously from the average of their neighbors. Examples of RFI from the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) Mission are also discussed.
Ruf, C., Chen, D., Le Vine, D., de Matthaeis, P., and Piepmeier, J. (28-Sep-15). Performance of the Radio Frequency Interference (RFI) detection and mitigation algorithms used by the Aquarius microwave radiometer is demonstrated on orbit. The detection algorithm makes use of the radiometer's high over-sampling rate to identify short, pulsed increases in power that are characteristic of radar operating nearby in the microwave spectrum. The mitigation algorithm is shown to remove nearly all detected RFI.
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A. and Tang, W. (31-Oct-12). Presented at the 2012 Aquarius Calibration/Validation Workshop at Goddard Space Flight Center.
Le Vine, D.M., Piepmeier, J.R., Dinnat, E.P., de Matthaeis, P., Utku, C., Abraham, S., Lagerloef, G.S.E., Meissner, T., and Wentz, F. (10-Sep-15). The Aquarius radiometers include several special features such as measurement of the third Stokes parameter, fast sampling, and careful thermal control, and a combined passive/active instrument. Aquarius is working well and in addition to helping measure salinity, the radiometer special features are generating new results.
Le Vine, D. (11-Nov-14). Aquarius is a NASA instrument comprising three L-band (1.4 GHz) radiometers dedicated to the remote sensing of global sea surface salinity. During the nominal operation, Aquarius' radiometers are calibrated using an internal hot target. An additional empirical adjustment is performed by comparing measured and simulated antenna temperatures over oceans.
Fore, A. (31-Oct-12). The results of radiometer calibration over the Amazon. Over land, significant ascending/descending bias was observed. Over the ocean, the data is not consistent with land estimates, and scaling is recommended.
Fore, A. (30-Jan-13). Findings include: no significant ascending/descending bias observed over Amazon for the three beams of Aquarius; and bias over the ocean is not consistent with land estimates for HH polarization.
de Matthaeis, P., Utku, C., Le Vine, D.M., and Moyer, A. (10-Sep-15). Aquarius brightness temperature data are used to calculate sea ice thickness in the Arctic region. The initial sea ice thickness values retrieved from Aquarius data are compared to the SMOSIce Data as well as to estimates from NASA's Operation IceBridge.The accuracy of retrieved Aquarius ice thickness is possibly influenced by uncertainties in the ancillary input parameters and by the coarser resolutions of Aquarius.
Presented at the 2012 AGU Fall Meeting
Lee, T., Lagerloef, G. S. E., Gierach, M. M., Kao, H-Y, Yueh, S. H., and Dohan, K. B. (03-Dec-12). Sea surface salinity (SSS) measurements from the Aquarius/SAC-D during September-December 2011 provide the first satellite observations of the salinity structure of tropical instability waves in the Pacific. The related SSS anomaly has a magnitude of approximately ±0.5 PSU.
Le Vine, D.M., de Matthaeis, P., Ruf, C., Chen, D., and Dinnat, E.P. (17-Sep-15). Monitoring salinity from space is a particularly sensitive measurement and RFI is a concern, even in the protected band at 1.4 GHz where the Aquarius radiometers operate. To protect against RFI, the Aquarius radiometer samples rapidly and a glitch detection algorithm is employed to check each sample for RFI.
Brown, S. (16-Nov-11). An overview of the objectives and logistics for the 2011 Calibration/Validation Workshop.
Jones, L. and Hejazin, Y. (28-Mar-12). This presentation describes the approach used to derive an ocean roughness correction for Aquarius. This correction involves using the microwave radiometer's brightness temperature to infer Ka-band ocean roughness. This is translated into L-band using an ocean surface emissivity radiative transfer model.
Wentz, F. and Meissner, T. (19-July-10). Detailed information was shared about the Aquarius "forward model", a comprehensive and accurate computer simulation of Aquarius' operation on orbit. Also discussed was the "inverse model", an Aquarius simulator used to develop retrieval algorithms and verify instrument performance.
Yueh, S., Wenqing, T., Fore, A., Hayashi, J.C.A., Lagerloef, G., Jackson, T., and Bindlish, R. (17-Sep-15). The primary science objective of the Aquarius mission is to monitor the seasonal and interannual variation of the large scale features of the surface salinity field in the open ocean.
Lagerloef, G.S. and Kao, H.Y. (26-Feb-14). The Aquarius satellite mission's measurement objectives include discovering unknown features in the sea surface salinity field, and documenting seasonal and interannual variations on regional and basin scales.
Lagerloef, G. and Kao, H. (11-Nov-14). The Aquarius measurement objectives are to describe unknown features in the sea surface salinity field and document seasonal and interannual variations on regional and basin scales. This presentation will first describe the structure of the mean annual global salinity field compared with the previous in situ climatology and contemporary in situ measurements , including small persistent biases of opposite sign in high latitudes versus low latitudes, currently under intense investigation, as well as global and regional error statistics.
Presented at the 2014 AGU Fall Meeting
Lagerloef, G. and Kao, H-Y. (18-Dec-14). The Aquarius satellite microwave sensor, launched June 2011 as part of the US-Argentina joint Aquarius/SAC-D mission, commenced observations on 25 August 2011, and completed three years of ocean surface salinity measurements in late August 2014.
Presented at the 95th AMS Meeting
Meissner, T. and Kao, H.Y. (07-Jan-15). The Aquarius satellite microwave sensor, launched June 2011, as part of the US-Argentina joint Aquarius/SAC-D mission, and commenced observations on 25 Aug2011, and completed three years of ocean surface salinity measurements in late August 2014. The Aquarius measurement objectives are to describe unknown features in the sea surface salinity (SSS) field, and document seasonal and interannual variations on regional and basin scales. This presentation will first describe the structure of the mean annual global salinity field compared with the previous in situ climatology and contemporary in situ measurements, including small persistent biases of opposite sign in high latitudes versus low latitudes, currently under intense investigation, as well as global and regional error statistics.
Lagerloef, G. and Kao, H-Y. (12-Apr-12). Presentation includes these conclusions: Argo buoy measurement differences are about 0.6 psu rms, with sea surface temperature > 0.5C and land fraction <0.0005; in high-latitude cold water regions, retrievals are biased high and much noisier; in the tropics, values are less than Argo, likely due to rainfall and surface stratification; there are residual quasi-monthly radiometer calibration errors resulting in +/-0.2 psu variations relative to Argo buoys; and ascending / descending passes have different bias trends, which could be a seasonal artifact.
Lagerloef, G. (11-Apr-12). Presentation includes seven-month mean global Aquarius data and some early scientific findings including: Eastern Pacific "Tropical Instability Waves", Amazon Plume dynamics in the tropical Atlantic, and east equatorial Pacific freshening from the Inter Tropical Convergence Zone. Results from an intercomparison between Aquarius and Argo in-water data are also discussed.
Yueh, S., Fore, A., Freedman, A., and Chaubell, J. (19-July-10). Detailed information about the Aquarius scatterometer, including: key requirements; technical approach; algorithm development status; plan for post-launch calibration/validation (cal/val); and remaining issues (e.g., development of operational simulator for Aquarius Data Processing System testing and analysis tools for cal/val).
Fore, A., Neumann, G., Freedman, A., Chaubell, M., Tang, W., Hayashi, A., and Yueh, S. (18-Nov-15). In this talk we discuss the Aquarius scatterometer calibration, starting with the instrument calibration, by assessing the scatterometer stability.
Fore, A., Neumann, G., Freedman, A., Chaubell, M, Tang, W., Hayashi, A., and Yueh, S. (18-Sep-17). An analysis of scatterometer calibration for Aquarius.
Fore, A., Tang, W., Hayashi, A., and Yueh, S. (13-Nov-14). In this talk, we show that Aquarius scatterometer calibration has provided stable L-band backscatter observations over the entire mission duration of more than three years. We analyze the calibration using the ocean as a reference, and we track the calibration stability using a numerical weather product coupled with an ocean geophysical model function.
Fore, A., Yueh, S., Tang, W., and Hayashi, A. (31-Mar-15). The results of the Aquarius Scatterometer Calibration, and the status of the effect of radio frequency interference (RFI) on the satellite signal.
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A. and Tang, W. (30-Jan-13). Findings include: scatterometer calibration drift, if any is small; seasonal ascending/descending difference observed; geographical variation observed up to ~0.5 dB; and deviation from expected Sigma0 differs most at high latitudes and near the inter tropical convergence zone.
Fore, A., Yueh, S. and Tang, W. (31-Oct-12). Wind speed was retrieved using scatterometer only and then with the Combined Active Passive (CAP) method. CAP was found to perform best, most significantly so at higher wind speeds.
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A., and Tang, W. (27-Mar-12). An analyis of the stability of the Aquarius scatterometer. In this analysis, no significant long-term trend was seen in the predicted vs. measured Sigma0.
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A. and Tang, W. (31-Oct-12). An analysis of scatterometer stability. A slight increase in Sigma0 over the mission was observed using double-difference. Most of the increas was in the first two to three months of the mission. The instrument may have contributed to this, and requires further investigation.
Schanze, J. (30-Mar-16). Aquarius-derived density (higher in cold and/or salty water) is available in the V4 product and spiciness (measure of hot and salty water) will be added to the V5 product. The definition of spiciness is now part of the Thermodynamic Equation of State 2010 (TEOS-10). Spiciness along isopycnals (i.e., line/surface of same density) is proportional to the water mass contrast and suited to study some mode water formation. In this presentation, density and spiciness were decomposed into thermal and haline components for Aquarius, along with Aquarius minus Argo. This study concludes that, in many areas, Aquarius provides significant temporal and spatial improvements over Argo. Continuity of L-band salinity measurements from SMAP (Soil Moisture Active Passive) and SMOS (Soil Moisture Ocean Salinity) allow the continuation of the density and spiciness record with the potential to gain new understanding of important questions related to mixing in the ocean.
Presented at the 2014 AGU Fall Meeting
Menezes, V., Vianna, M., and Phillips, H. (18-Dec-14). In the present work, a thorough analysis of the first 2 years of Aquarius SSS data in the South Indian Ocean is performed together with the Argo and RAMA data. This analysis is focused into 3 questions: How accurately is Aquarius observing the fresh Indonesian Throughflow and the salty subtropical waters? Can Aquarius give a spatial context for interpreting the data measured by the RAMA mooring system, which are highly resolved in time, but very sparse in space? Can westward propagating seasonal signals be observed in the Aquarius SSS fields as recently described in model simulations?
Lee, T. (11-Nov-14). This presentation highlights the new understanding of tropical instability waves (TIWs) and Madden-Julian Oscillation enabled by the applications of Aquarius data. For the Pacific, Aquarius data provided a better view of TIW at the equator because of the large meridional gradient of sea surface salinity there, and revealed a shorter dominant period and faster propagation of TIWs at the equator than those at off-equatorial latitudes.
Hacker, P., Melnichenko, O., Maximenko, N., and Potemra, J. (26-Feb-14). The Aquarius/SAC-D satellite provides an opportunity to observe near-global sea surface salinity (SSS) with unprecedented space and time resolution not available from other components of the Global Ocean Observing System. In order to evaluate and quantify the potential utility of the SSS data for global and regional studies of SSS variability, our research group has been using the Level-2, three-beam swath data and Argo data to characterize and quantify random errors and systematic biases on a global grid.
Jackson, T., Bindlish, R., Cosh, M., Zhao, T., and Holmes, T. (11-Apr-12). Presentation summary includes: initial approach to soil moisture retrieval results are encouraging and consistent with expected spatial patterns, SMOS, and model soil moisture; the algorithm will be implemented in the Aquarius processor to provide a separate soil moisture product; and scatterometer and Microwave Radiometer (MWR) calibrations needed to further investigate vegetation parameterization and land surface temperature.
Bindish, R. (28-Mar-12). The baseline soil moisture algorithm uses the radiative transfer equation (t-w model) and H pol observations along with ancillary data to estimate soil moisture. A difference between the Aquarius and SMAP implementation is the need to incorporate incidence angle effects.
Jackson, T., Bindlish, R., and Zhao, T. (16-Nov-11). The baseline soil moisture algorithm uses the radiative transfer equation (t-w model) and H pol observations along with ancillary data to estimate soil moisture. A difference between the Aquarius and SMAP implementation is the need to incorporate incidence angle effects.
Jacob, M.M., Ebrahimi, H., Santos-Garcia, A., Jones, W.L., and Asher, W. (26-Feb-14). After analyzing over two years of Sea Surface Salinity (SSS) data from Aquarius (AQ), it is observed that the spatial patterns of delta-SSS (differences between the Hybrid Coordinate Ocean Model and AQ measurements) can often be associated with rainfall events. This begs the question "Is it science (sea water freshening) or AQ retrieval errors?" This paper examines this question and presents several hypotheses that are compared with empirical SSS observations.
Melnichenko, O., Hacker, P., Maximenko, N., Lagerloef, G., and Potemra, J. (12-Nov-14). A new high-resolution sea surface salinity (SSS) analysis has been produced at the International Pacific Research Center of the University of Hawaii using Aquarius Level-2 (swath) data from September 2011 to August 2014. The primary product is a weekly SSS analysis on a nearly-global 0.5-degree grid. The analysis method is optimum interpolation that takes into account analyzed errors on the observations, specific to the Aquarius instrument.
Jones, W.L., Hejazin, Y., Jacob, M., and Rabolli, M. (17-Nov-15). Salinity microwave remote sensing is challenging due to the corrections required to obtain the smooth ocean surface brightness temperature from which SSS is derived. The largest error source is the surface warming due to oceanic winds, and the AQ/SAC-D baseline approach uses the AQ-scatterometer (Scat) measurement of ocean radar backscatter to infer L-band excess ocean emissivity associated with wind roughness.
Hacker, P., Melnichenko, O., Maximenko, N., and Potemra, J. (12-Nov-14). The Aquarius/SAC-D satellite provides an opportunity to observe near-global sea surface salinity (SSS) with unprecedented space and time resolution not available by other components of the Global Ocean Observing System. In order to evaluate and quantify the potential utility of the SSS data for global and regional studies of SSS variability, our research group has been using the Level-2, three-beam swath data and Argo data to characterize and quantify systematic space/time biases and random errors on a global grid.
Meissner, T. (29-Mar-16). This presentation covered the evaluation of various sea surface temperature (SST) products including: NOAA Optimum Interpolation (Reynolds), WindSat, Canada Meteorological Center (CMC), Multi-scale Ultra-high Resolution (MUR), and UKMet Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA ). All three products that use microwave SST (WindSat, CMC, MUR) perform slightly better than Reynolds, particularly in cold water / at high latitudes. For future Aquarius algorithms, it is recommended to use the CMC product.
Gordon, A. (11-Nov-14). For decades oceanographers have had global near synoptic time series views of the sea surface from space, including, in addition to visible images, temperature, height, color, sea ice, wind and marine rainfall patterns, all of which have dramatically expanded our knowledge of the ocean condition, enabling quantitative investigating of ocean processes and their coupling to the atmosphere/climate and marine ecosystems. But only recently have we gathered from orbiting satellites views of the sea surface salinity, with the advent of ESA's Soil Moisture and Ocean Salinity (November 2009 launch) and of NASA/CONAE Aquarius/SAC-D satellite mission (June 2011 launch).
Sen, A. (15-Nov-11). The current status and overview of Aquarius since launch. Includes a review of the commissioning and orbit checkout timeline, and the status of the observatory. The observatory remains healthy, and the SAC-D instrument have been commissioned. The Aquarius instrument has met all success criteria n the PLAR and is ready for operations.
Guan, B., Lee, T., Halkides, D.J., and Waliser, D.E. (13-Nov-13). Sea surface salinity (SSS) measurements from Aquarius were analyzed along with precipitation and sea surface temperatures to characterize and understand the SSS signature of the Madden-Julian Oscillation (MJO) over the 2-yr period for which Aquarius data are currently available. In this presentation, the authors conclude that (1) Aquarius detects the MJO signature in SSS; (2) Indian Ocean SSS changes are primarily forced by precipitation during wet phases; ocean dynamics plays an important role in the western Pacific; (3) salinity has important contributions to the surface density anomaly; and (4) salinity plays a dominant role in surface perturbation potential energy.
Utku, C., Le Vine, D.M., Abraham, S., and Piepmeier, J. (28-Sep-15). One of the unique features of the L-band radiometers comprising Aquarius is the presence of a polarimetric channel to measure the third Stokes parameter.mThe purpose is to provide a measure of Faraday rotation, which can be important for remote sensing at L-band, especially in the case of remote sensing of salinity which requires high precision.
Meissner, T. and Wentz., F. (18-Sep-17). A walkthrough of the differences in the Aquarius Version 5 data as compared to Version 5, including discussion of remaining biases.
Lagerloef, G. and Kao, H. (17-Jan-17). Aquarius sea surface salinity (SSS) retrievals are compared with co-located Argo buoy data using three processing versions: 4.0, 4.5.0, and 4.5.1. The first sets of maps show SSS differences over the globe (combined, ascending orbits only, and descending orbits only). Histograms, time-series graphs, and daily global averaged standard deviations of of combined data are then separated by the three Aquarius beams for each processing version. One set of time-series graphs show the daily median of global ascending minus descending for each beam, followed by median data binned into latitude bands. The final histograms show differences between Aquarius, in-situ buoy, and Hybrid Coordinate Ocean Model (HYCOM) data.
Kao, H-Y., Lagerloef, G. and Carey, D. (26-Mar-12). The trends of Aquarius salinity measurements for all beams were compared between Version 1.2.2 and 1.2.3.
Gunn, J. (20-July-10). Overview of the Aquarius Validation Data System (AVDS) whose objectives are to: collect appropriate in situ surface salinity data for comparison with Aquarius/SAC-D satellite surface salinity measurements; and make these data and associated match-ups available to the user community at large.
Kao, H-Y., Lageloef, G., and Carey, D. (18-Sep-17). Validation of Aquarius results from Version 2 data to Version 5 data showing the improved root square mean error across those versions.
Kao, H-Y. (31-Mar-15). An overview of the validation efforts for Aquarius, using Argo (in-situ measurements) and HYCOM models for Version 3.0 and 3.4 data.
Bindlish, R., Jackson, T., Zhao, T., Lagerloef, G., and Le Vine, D. (29-Jan-13). Findings include: Aquarius observations compare well with SMOS observations over oceans; Aquarius observations are very stable over Dome-C; and SMOS observations are lower than Aquarius observations for all channels over land.
Dinnat, E.P., Le Vine, D.M., Bindlish, R., Piepmeier, J.R., and Brown, S.T. (10-Sep-15). Aquarius is a spaceborne instrument that uses L-band radiometers to monitor sea surface salinity globally. Other applications of its data over land and the cryosphere are being developed. Combining its measurements with existing and upcoming L-band sensors will allow for long term studies.
Presented at the 2012 AGU Fall Meeting
Yueh, S.H., Tang, W., Fore, A., Freedman, A.P., Neumann, G., Hayashi, A., and Lagerloef, G.S.E. (03-Dec-12). The Aquarius/SACD satellite was launched on June 10, 2011, and the Aquarius instrument has been operational since August 25, 2012. Aquarius is a combined passive/active L-band microwave instrument developed to map the salinity field at the surface of the ocean from space. The primary science objective of the Aquarius mission is to monitor the seasonal and interannual variation of the large scale features of the sea surface salinity field in the open ocean with a spatial resolution of 150 km and a retrieval accuracy of 0.2 psu globally on a monthly basis.
Yueh, S., Tang, W., Fore, A., Hayashi, A., Lee, T., Lagerloef, G., Bindlish, R., Jackson, T., Murty, V., and Papa, F. (16-Apr-13). Aquarius is a combined passive/active L-band microwave instrument developed to map the sea surface salinity (SSS) field from space. This paper describes Aquarius' version-2.0 (V2.0) Combined Active-Passive (CAP) retrieval algorithm for simultaneous retrieval of surface salinity and wind.
Yueh, S., Tang, W., Fore, A., Chaubell, J., Freedman, A., and Hayashi, A. (30-Jan-13). Findings are: (1) CAP is more accurate than the L2 product, (2) the Aquarius salinity product (CAP) is about 0.25 psu RMS for 28-day average, and (3) Aquarius CAP wind speed is highly accurate (0.7 m/s error) - slightly better than SSM/I.
Biswas, S.K., Jones, L., Rocca, D., and Gallio, J.-C. (28-Sep-15). The K/Ka-Band Microwave Radiometer (MWR) on-board Aquarius/SAC-D mission is described here with details on its radiometric calibration. The calibration is separated in two major instrument parts viz. receiver and antenna switch-matrix. An on-orbit calibration using Naval Research Laboratory's WindSat radiometer is used to determine antenna pattern correction coefficients and residual biases.
Lagerloef, G. (19-July-10). Overview of how mission simulator data informed the Aquarius/SAC-D mission design and sampling strategy. Information was shared about the following simulators: operational mission; Aquarius algorithm; standard deviation error; scatterometer; and "2007 science simulator".
Torrusio, S., Caruso, D. and Sen, A. (19-July-10). Overview includes: mission summary; key partners and centers; observatory design; updates since the previous science team meeting; and schedule and milestones leading up to Aquarius/SAC-D launch.
Bindlish, R., Jackson, T., and Cosh, M. (13-Nov-14). Although Aquarius was designed for ocean salinity mapping, our objective in this investigation is to exploit the large amount of land observations that Aquarius acquires and extend the mission scope to include the retrieval of surface soil moisture.
Jackson, T. and Karszenbaum, H. (19-July-10). Presentation included information on: passive, active, and combined microwave soil moisture algorithms; basis of passive microwave soil moisture algorithms; strategy for developing an Aquarius baseline soil moisture algorithm; validation; recent field campaigns (e.g., CanEx); and updates of related Aquarius/SAC-D projects.
Meissner, T., Went, F., and Manaster, A. (17-Jan-17). Five proposed changes to the Aquarius geophysical model function (GMF) for Version 5 (V5) are outlined, some of which have been already been incorporated into evaluation processing version and others brand new. These changes include using sea surface temperature data (SST) from the Canadian Meteorological Centre, reflected galaxy data from SMAP, updated galaxy symmetrization (i.e., to 50% of current), oxygen (O2) absorption based on Liebe et al., and adjusting SST dependence of wind-induced emissivity. The final slide outlines the proposed actions towards V5.
Le Vine, D.M., Lagerloef, G.S.E., Ruf, C., Wentz, F., Yueh, S., Piepmeier, J., Lindstrom, E., and Dinnat, E. (28-Sep-15). This paper provides an overview of the instrument and an example of initial results of the Aquarius/SAC-D mission.
Vinogradova, N.T., Ponte, R.M., Piecuch, C.G., and Little, C.M. (25-Feb-16). During the past two decades, most surface waters around Greenland ice sheet and in the Nordic Seas became significantly saltier. Here we assess what controls contemporary salinity changes by examining various terms of the salinity budget, including the dilution effect due to air-sea fluxes of freshwater, fluxes of salt due to sea ice formation/melting, and ocean fluxes of salinity associated with advective and diffusive processes.
Yueh, S., Tang, W., and Hayashi, A. (17-Nov-11). The ascending and descending passes of salinity retrieval are different, and show a systematic regional bias between ascending and descending passes. There does not appear to be an obvious connection with the salinity bias.
Hong, L. (30-Jan-13). Findings include: galactic background is an important factor of remaining geophysical model errors; simple linear adjustment is an applicable correction to the current model; and other error sources are to be analyzed in residual dTf biases.
Melnichenko, O., Hacker, P., Maximenko, N. and Potemra, J. (31-Oct-12). This presentation discusses the differences in the ascending and descending swaths of Aquarius data, as well as potential sources for the differences.
Misra, S. and Brown, S. (29-Jan-13). Findings include: exponential drift correction successfully removes observed drift over Antarctica; calibration wiggles are observed in Antarctic model differences and have the same magnitude as those observed over the ocean; and calibration wiggles are observed over warm rainforest regions in inter-channel differences and have a similar magnitude as those observed over the ocean.
Lagerloef, G. and Carey, D. (17-Jan-17). Empirical orthogonal function (EOF) analysis of Aquarius data has been performed to determine radiometer drifts without reference to the Hybrid Coordinate Ocean Model (HYCOM). This study focused on decomposition of two evaluation datasets (V4.2.0 and V4.2.1) using vertically-polarized Channel 1 (1V) data for the entire Aquarius mission. Based on these preliminary results, the next step is to re-analyze data using ocean provinces (North Pacific, North Atlantic, etc.)
Song, Y.T., Yueh, S., Moon, J-H., and Qu, T. (13-Nov-13). Using two different Aquarius sea-surface-salinity (SSS) datasets, Argo in-situ measurements, and two ocean models, the authors assessed the ability of Aquarius to observe seasonal variability of global SSS. Conclusions are: (1) regional differences between Aquarius and ARGO can be explained by high E-P and R variability; and (2) Aquarius shows a clear advantage over ARGO in river discharge regions.
Meissner, T., Wentz, F., Scott, J., and Hilburn, K. (26-Nov-14). The Aquarius Version 3.0 salinity product has been released to the public in June 2014. The retrieval algorithm and the quality of the data constitute a major improvement from earlier versions. Our presentation starts with a brief overview of the major components of the Aquarius V3.0 salinity retrievals and upgrades that were implemented since prior releases.
Meissner, T., Wentz, F., Scott, J., and Hilburn, K. (13-Nov-14). Fresh biases up to 0.4 psu are observed when comparing Aquarius salinities with ARGO or HYCOM in the tropical and subtropical regions. These biases are partly due to inaccuracies in the geophysical model function that correlate with sea surface temperature and partly due to salinity stratification in the upper ocean layer. Aquarius measures salinity within a few centimeters of the surface, which is fresher during and after rain effects than the 5 m depth layer, to which ARGO and HYCOM refer to. In order to make improvements to the salinity retrieval algorithm and avoid overcorrecting it is essential to separate these two effects.
Li, C., Zhao, H., Li, H., and Lv, K. (31-July-15). The study of sea surface salinity (SSS) plays an important role in the marine ecosystem, estimation of global ocean circulation and observation of fisheries, aquaculture, coral reef and sea grass habitats. Three statistical methods without considering the physical effects of the input parameters are proposed to calculate the sea surface salinity from SMOS measured TB values and associated auxiliary data.
Bianchi, J., Quirno, M., Lozza, H., Thibeault, M., Dadamia, D., and Goniadzki, D. (13-Nov-14). The impact on discharge simulation efficiency of satellite soil moisture data assimilation was assessed. Soil moisture estimation products of the instruments SMOS, Aquarius and AMSR2 were assimilated through Ensemble Kalman Filtering into two previously-calibrated conceptual hydrological models of the Gualeguay basin, located in the Argentinian temperate sub-humid flatlands.
Presented at the 2014 AGU Fall Meeting
Dinnat, E., Brucker, L. and Álvarez, I.O.C. (18-Dec-14). Aquarius is a NASA space-borne instrument operating three L-band radiometers. While Aquarius SSS retrievals are performed with a good accuracy in tropical and mid-latitude oceans, a thorough assessment has not been performed in the colder waters of the polar oceans. To assess Aquarius data at high latitudes, we compare them to in-situ measurements from ship cruises.
Chen, C.W., Piepmeier, J.R., Johnson, J.T., and Ghaemi, H. (28-Sep-15). This paper discusses the impacts of radio frequency interference on the NASA Soil Moisture Active and Passive mission's radar and radiometer.
Brown, S. (13-Nov-13). This paper presents an overview of the MWR brightness temperature calibration including: (1) MWR can be used to retrieve water vapor, cloud liquid water, wind and rain over the ocean; (2) the objective is to apply techniques used to calibrate the Jason series altimeter radiometers to MWR; and (3) since the MWR swath is formed from independent beams, it is critical to assess inter-beam calibration biases over the full dynamic range of the instrument.
Martin, M., King, R., While, J., and Aguilar, A. (07-Nov-18). The UK Met Office ocean forecasting system (FOAM - Forecasting Ocean Assimilation Model) runs once per day and produces analyses and 6-day forecasts of the 3D ocean and sea-ice. There is a need to assimilate sea surface salinity (SSS) data because the Argo salinity coverage is limited, and the current model has large areas where there are precipitation and river inputs. The freshwater imbalances can affect other model outputs (sea surface height, circulation). The assimilation of daily satellite SSS from SMOS, Aquarius and SMAP were implemented and assessed during the 2015-2016 El Niño. The largest reduction in error was from the combination of SMOS and SMAP. The assimilation also led to improvements in temperature and sea surface height outputs in the Central Equatorial Pacific. The continuity of satellite salinity measurements would help the case for operational implementation, and more in situ data would greatly improve the bias correction and impact of the assimilated satellite data.
Presented at the 2014 AGU Fall Meeting
Mehra, A., Nadiga, S., Bayler, E., and Behringer, D. (18-Dec-14). Recently available satellite sea-surface salinity (SSS) fields provide an important new global data stream for assimilation into ocean forecast systems. In this study, we present results from assimilating satellite SSS fields from NASA's Aquarius mission into the National Oceanic and Atmospheric Administration's (NOAA) operational Modular Ocean Model version 4 (MOM4), the oceanic component of NOAA's operational seasonal-interannual Climate Forecast System.
Presented at the 95th AMS Meeting
Mehra, A., Nadiga, S., Bayler, E., and Behringer, D. (07-Jan-15). Recently available satellite sea-surface salinity (SSS) fields provide an important new global data stream for assimilation into ocean forecast systems. In this study, we present results from assimilating satellite SSS fields from NASA's Aquarius mission into the National Oceanic and Atmospheric Administration's (NOAA) operational Modular Ocean Model version 4 (MOM4), the oceanic component of NOAA's operational seasonal-interannual Climate Forecast System (CFS).
Goniadzki, D., Thibeault, M., Lozza, H., Quirno, U., Dadamia, M., and Bianchi, J. (12-Nov-13). This project aims at developing assimilation techniques of SAC-D soil moisture retrievals into operational hydrologic models at catchments within the Del Plata basin.
Uriburu Quirno, M. and Goniadzki, D. (17-Nov-15). The National Water Institute carried out a project called "Assimilation of Soil Moisture Estimates into Flow-Forecasting Hydrologic Models" with the purpose of implementing a hydrologic model that included mission soil moisture retrievals, to be used in basin-outlet flow simulation and forecast at two lowland catchments in Argentina (Gualeguay River and Pergamino Brook). The main quantitative project outcomes are summarized, including human resources training, publications, procurement of instruments and equipment, and field campaigns.
Fratantoni, D.M. and Hodges, B.A. (26-Feb-14). As a contribution to the Salinity Processes in the Upper Ocean Regional Study (SPURS) field program, we used a combination of high-endurance autonomous surface vehicles (the Liquid Robotics Wave Glider) and short-endurance autonomous underwater vehicles (the OceanServer Iver2) to characterize upper-ocean salinity structure and variability on historically undersampled scales.
Lagerloef, G. (19-July-10). Overview of the baseline orbit for the Aquarius/SAC-D satellite and factors that went into choosing it. Examples of nadir track lines and Aquarius beams' locations were shared for the western South Atlantic, Labrador Sea, several ocean mooring locations, and the SPURS study site (i.e., subtropical North Atlantic salt maximum).
D'Addezio, J., Subrahmanyam, B., Nyadjro, E., and Murty, V. (11-Nov-14). The Northern Indian Ocean presents a unique dipolar sea surface salinity structure with the salty Arabian Sea on the west and the fresher Bay of Bengal on the east. At the surface, the largest driver of seasonal salinity variability is the monsoonal riverine runoff and winds and their ability to transport volume between the two basins.
Chaitanya, A.V.S., d'Ovidio, F., Lengaigne, M., Vialard, J., Papa, F., and Riotte, J. (08-Nov-18). This work examines how the Bay of Bengal circulation redistributes localized freshwater inputs into the Northeastern portion of the bay during the monsoon season. Previous work has revealed that eddy stirring may play a large role in this re-distribution. The seasonal cycle and Indian Ocean Dipole (IOD) may also affect these patterns. Rain was found to dominate the freshwater distribution, except for areas near estuaries in December of the study year. The Ganges was found to contribute 40-60% of the freshwater along the east coast of India. Effects from rain dominate the interior of the Bay of Bengal, with most local rain remaining in the north and being input in the southern region. Using a Lagrangian approach may help to quantify the relative roles of eddies, the IOD and seasonal circulation.
Akhil, V.P., Vialard, J., Lengaigne, M., Keerthi, M.G., Vergely, J-L., and Boutin, J. (06-Nov-18). Modelling and fishermen's accounts have long suggested that the Ganges-Brahmaputra plume forms a "river in the sea", which is advected southward by the East India Coastal Current following the monsoon and modulated by the Indian Ocean Dipole. Eight years of SMOS data coupled with Aquarius observations confirm this phenomenon, although the period of measurement is still too short to identify the signature of Ganges-Brahmaputra interannual variability.
Ruff, C. and Chen, D. (15-Nov-11). The results of a ground-based beacon overpass, positioned at the inner and outer beam edges.
Tranchant, B., Greiner, E., and Lellouche, J. (25-Feb-16). SSS has been measured from space for the past 6 years with the SMOS and Aquarius missions. These two missions should have filled the gaps in the current in-situ network. Few data assimilation experiments have been realized. In this study, we propose to estimate and remove the large scale bias with the operational ocean forecasting system at 1/4°.
Presented at the 2012 AGU Fall Meeting
Masuelli, S., Labanda, M.F., Marenchino, M., and Jacob, M.M. (04-Dec-12). The National Space Agency of Argentina (CONAE, Comisión Nacional de Actividades Espaciales) developed the SAC-D/Aquarius science mission (launched in June 2011), together with the National Aeronautics and Space Administration of the USA (NASA). The main Argentinean sensor aboard the SAC-D is the MWR (Micro Wave Radiometer). This instrument is a three channel push-broom microwave radiometer with 8 antenna beams per channel and two different incident angles (52 and 58 degrees), that provides a measurement swath of approximately 380 km. These channels provide 36.5 GHz dual horizontal and vertical polarized and 23.8 GHz horizontal polarized radiance measurements in an overlapping swath with the L-band Aquarius radiometer/scatterometer. The main objective of this instrument is to retrieve sea geophysical variables such as columnar water vapor, wind speed, sea ice concentration and rain detection.
Dogliotti, A.I., Williams, G., Simionato, C., Lutz, V., Gossn, J.I., and Tropper, I. (19-Nov-15). The Argentine shelf and its shelf-break comprise a large and rich biological area of the ocean. Remote sensing of ocean color has demonstrated to be a very useful tool for monitoring the active and dynamic marine ecosystem providing near real-time, long-term, synoptic, global estimates of key parameters, such as surface chlorophyll-a (chl-a) concentration.
Martinez, J., Olmedo, E., Gonzalez-Gambau, V., Turiel, A., and Yueh, S. (23-July-17). A new debiased non-Bayesian methodology has demonstrated to be very effective for the retrieval of Sea Surface Salinity (SSS) from brightness temperature (TB) measured by Soil Moisture and Ocean Salinity (SMOS) interferometric radiometer. Applying this methodology it is possible to retrieve SSS values in marginal seas or cold waters where the operational retrieval does not.
Biswas, S.K., Jones, L., Gallo, J-C., and Rocca, D. (17-Nov-11). The calibration performed on the Aquarius/SAC-D microwave radiometer for the brightness temperature.
deCharon, A., Companion, C., Cope, R., and Taylor, L. (11-Nov-14). NASA's Aquarius instrument and Salinity Processes in the Upper Ocean Regional Study (SPURS) have given the scientific community unprecedented insight into salinity's role in the earth system. Synergistic efforts by the University of Maine-based public engagement team have focused on themes of the water cycle, ocean circulation and climate. Resources highlighting salinity's ties to these familiar topics have been disseminated through Aquarius and SPURS webinars and workshops.
Presented at the 2016 AGU Fall Meeting
Melnichenko, O., Hacker, P.W., Wentz, F.J., Meissner, T., Maximenko, N.A., and Potemra, J.T. (07-Nov-17). To address the need for a consistent, continuous, long-term, high-resolution sea surface salinity (SSS) dataset for ocean research and applications, a trial SSS analysis is produced in the eastern tropical Pacific from multi-satellite observations. The new SSS data record is a synergy of data from two satellite missions. The beginning segment, covering the period from September 2011 to June 2015, utilizes Aquarius SSS data and is based on the optimum interpolation analysis developed at the University of Hawaii. The analysis is produced on a 0.25-degree grid and uses a dedicated bias-correction algorithm to correct the satellite retrievals for large-scale biases with respect to in-situ data.
Melnichenko, O., Hacker, P., Meissner, T., Wentz., F., and Potemra, J. (28-Aug-18). To address the need for a consistent, continuous, long-term, high-resolution sea surface salinity (SSS) dataset for ocean research and applications, a trial SSS analysis is produced in the eastern tropical Pacific from multi-satellite observations. The new SSS data record is a synergy of data from two NASA satellite missions. The beginning segment, covering the period from September 2011 to June 2015, utilizes Aquarius SSS data and is based on the optimum interpolation analysis (OI SSS) developed at the University of Hawaii.
Brown, S. (29-Mar-16). In this presentation, the focus and format of the workshop were defined along with objectives (e.g., state of current Aquarius V4.2 product, assess progress of yet-to-be-implemented V5 updates) and key questions to be addressed during the meeting.
Brown, S. (17-Jan-17). The meeting kicked off with an overview of its focus and format. A summary of the previous in-person Cal/Val Meeting (March 2016), including “marching orders,” set the stage for key issues to tackle before the final release (Version 5) of Aquarius salinity data processing. The presentation concludes with a list of meeting objectives.
Lagerloef, G. (17-Jan-17). Aquarius Principal Investigator, Gary Lagerloef, provided his perspective on the open issues facing the Aquarius Cal/Val team under the general categories of latitude bias (in salinity data), sensor calibration, and geophysical errors. He suggested separating sensor drift from geophysical model errors and possibly revisiting radar calibration over the entire Aquarius mission.
Misra, S., Piepmeier, J.R., Peng, J., Mohammed, P., Hudson, D., De Amici, G., Dinnat, E., Le Vine, D., Bindlish, R., and Jackson, T. (10-July-16). In this paper we discuss the steps taken for the calibration and validation of the Soil Moisture Active Passive (SMAP) L-band radiometer. We discuss the use of multiple vicarious sources such as the global ocean mean and celestial cold-sky emissions along with various spacecraft maneuvers to calibrate out gain, offset, antenna pattern of the radiometer. We present initial validation comparison of SMAP brightness temperatures with other L-band missions.
Bruscantini, C.A., Maas, M., Grings, F., and Karszenbaum, H. (10-Sep-15). This study reports the calibration results obtained by a land cross-calibration between Windsat and the Microwave Radiometer.
Colazo, M.E. (17-Nov-15). CARMEN-1 is a package of instruments aboard SAC-D that includes components dedicated to the study of space radiation on advanced components, as well as the impact of micrometeoroids and micro orbital debris in the space environment. An overview of the availability data products and summary of CARMEN-1 measurements is provided.
Presented at the 2014 AGU Fall Meeting
Reagan, J., Boyer, T., Antonov, J, and Zweng, M. (18-Dec-14). This study attempts to advance our understanding of interannual changes in sea surface salinity by looking at year to year changes in the seasonal cycle over the past decade.
Reagan, J., Boyer, T., Antonov, J., and Zweng, M. (26-Nov-14). The Argo program has provided the scientific community with near-global, seasonally uniform coverage of hydrographic profiles over the past decade. Recent launches of the SAC-D/Aquarius and SMOS satellites have provided near real-time snapshots of global ocean sea surface salinity (SSS). The importance of understanding changes in SSS in both time and space cannot be overstated as it is a direct reflection of changes in our global hydrological cycle and is a major component of ocean circulation. This study attempts to advance our understanding of interannual changes in SSS by looking at year to year changes in the seasonal cycle over the past decade.
Park, J-J., Park, K-A., Kang, C-K., and Liu, W.T. (12-Feb-18). The accuracy of satellite-observed sea surface salinity (SSS) in the northwest Pacific was evaluated by comparing with in situ salinity measurements from Argo floats and buoys. Differences between satellite SSS and in situ measurements indicated their dependence on geolocation, sea surface temperature (SST), and other oceanic and atmospheric conditions.
Bingham, F., Busecke, J.J.M, Gordon, A.L., and Giulivi, C.F. (24-Feb-16). The surface salinity (SSS) in the eastern South Pacific study area is associated with high evaporation and surface Ekman convergence, weak variability and seasonality on the northern side, fluctuating size driven by changes in southward extent, mean surface currents flowing toward and through the feature from the north, and higher tendency for fresh anomalies on northern side. These characteristics highlight the role of mesoscale stirring and northward Ekman transport in the formation and maintenance of this prominent feature.
Misra, S. and Brown, S. (16-Apr-13). Previous high frequency microwave radiometers such as TOPEX, Jason-1, and Jason-2 have all utilized external brightness temperature references as calibration targets. Global mean brightness temperature measurements (or vicarious cold brightness temperatures) from the ocean are used to calibrate the instrument at one end of the temperature spectrum and hot targets such as the Amazonian rainforests are used at the other end of the temperature spectrum.
Guzmán, G., Duque, E.M., Hoyos, C., and Cardona, Y. (25-Feb-16). At the Eastern Tropical Pacific between the Panama Bight and the Galapagos Island a large region of low sea surface salinity (SSS) that exhibits a strong seasonal cycle and distinct spatial pattern. The mechanisms controlling the spatial and temporal variability of the SSS at this region are far from being fully understood. So, this work aims to present a characterization of the interannual variability of SSS in the region delimited by 4°S-10°N and 100°W-75°W through satellite observations and numerical modeling.
Regan, H., Lique, C., and Armitage, T. (09-Nov-18). The Arctic Basin stores a large amount of freshwater and most of this storage occurs in the Beaufort Gyre, a wind-driven ocean current located in the western part of the Arctic Ocean. In situ measurements show that the gyre has increased in size, intensified, and shifted northwest since 2003. The objectives of this study are to characterize the time and space variability of the gyre and the roles of atmospheric forcing and bathymetric interaction.
Patt, F. and Meissner, T. (01-Apr-15). On the final day of the workshop, there was a discussion of the status and clean-up efforts of the L2 data files. The discussion included an overview of what variables are currently found in the L2 files, which can be eliminated, and whether there are any variables or other information that need to be added.
Patt, F. and Meissner, T. (01-Apr-15). On the final day of the workshop, there was a discussion of the status and clean-up efforts of the L2 data files. The discussion included an overview of what variables are currently found in the L2 files, which can be eliminated, and whether there are any variables or other information that need to be added.
Ruiz-Etcheverry, L., Maximenko, N., and Melnichenko, O. (22-May-17). Marine fronts are narrow boundaries that separate water masses of different properties. These fronts are caused by various forcings and believed to be an important component of the coupled ocean-atmosphere system, particularly in the tropical oceans. In this study, we use three years of sea surface salinity (SSS) observations from Aquarius satellite to investigate the spatial structure and temporal variability of six main frontal SSS features in the tropical Atlantic, their evolution between seasons and differences between individual years.
Lambin, J. (15-Apr-13). Latest news from the CNES ocean program, CNES participation and recent developments (SMOS), and future plans and conclusions.
Kim, S-B., Chan, S., Yueh, S., and Lee, J-H. (28-Mar-12). Presented at the 2012 Aquarius Calibration/Validation Workshop in Santa Rosa, CA.
Le Vine, D. and Gallo, J. (20-July-10). Presentations include: definition, objectives, requirements, and approach to cold sky calibration of the Aquarius radiometers; and overview, considerations, and assumptions of the cold sky calibration maneuvers for the Microwave Radiometer (MWR).
Freedman, A. (27-Mar-12). Reviewing the results of Cold Sky Calibration (CSC), several scatterometer bumps were observed. The origin and impact of these bumps are discussed.
Dinnat, E. and Le Vine, D. (17-Jan-17). Aquarius cold sky calibration (CSC) maneuvers were performed to determine global biases over time for the various Aquarius channels (i.e., 1, 2, 3 for vertical and horizontal polarizations). Improvement is shown from historic processing to the most recent published version (4.0) and current evaluation version (4.5.1). These data have been used to assess temporal instrument drift such as “wiggles,” along with hardware temperature fluctuations over time.
Dinnat, E., Le Vine, E. and Abraham, S. (27-Mar-12). A quick look at the Cold Sky Calibration (CSC) efforts, and a comparison of the results to simulations.
Dinnat, E. (29-Jan-13). Findings include: at all beams/polarizations, the scale model predicts a better range of Ta than the GRASP 2012, but GRASP model is better in other respects.
Misra, S., Bosch-Lluis, J., Latham, B., Felten, C., Ogut, M., Brown, S., Lee, T., and Yueh, S. (30-Apr-19). A 2018 field experiment was conducted in the Arctic to test the sensitivity of wide-band spectroradiometry (i.e., CubeRRT) to sea surface salinity in cold waters. Measurement and calibration challenges were encountered due to foam, waves, mixed ice, radiofrequency interference (RFI), and galactic reflection. Lessons learned will be applied to future work.
Epeloa, J.E. and Meza, M.A. (17-Nov-15). The aim of this work is the retrieving atmospheric integrated columnar water vapor (CWV) over land surface by using the microwave radiometer (MWR) on board of the Scientific Argentine Satellite (SAC-D).
Yueh, S., Tang, W., Fore, A., Chaubell, J., and Hayashi, A. (17-Nov-11). The Combined Active-Passive (CAP) algorithm to retrieve wind vectors is analyzed. It is found that CAP can produce consistent SSS and wind retrievals, and it is more accurate by about 25% on average and 50-100% more accurate for high winds.
Song, T.Y., Lee, T., Yue, S., and Qu, T. (18-Nov-15). Using a recently developed ESSL (extended surface-salinity layer) model [Song et al., JGR, 2013], we have examined the near-surface salinity stratifications with emphasis on understanding of the dynamical processes that differ from one region to another.
Reagan, J.R., Boyer , T., and Zweng, M. (25-Feb-16). Multiple studies have shown that long-term salinity trends are indicative of an amplification of the global hydrological cycle, with salty regions of the ocean becoming saltier, and fresh regions of the ocean becoming fresher. However, are these long-term salinity trends consistent over the entire period, or are they dominated by medium and short-term salinity variability?
Presented at the 2016 AGU Fall Meeting
Asher, W., Thompson, E.J., Drushka, K., Jessup, A.T., and Schanze, J.J. (16-Dec-16). Salinity stratification in the ocean due to rain affects the spatial and temporal variability of heat, salinity, and momentum in the near-surface layer of the ocean. However, the relative importance of rain in driving surface variability of the ocean is not fully understood because routine observations have not been able to quantify either the spatio-temporal variability of rain or the response of the underlying ocean to rain. Relatively high resolution (10 km, 30 min) NASA GPM IMERG rain rate data, now available over much of the globe, can be used with in situ measurements of temperature and salinity in the upper few meters of the ocean to understand how rainfall patterns over scales of tens to hundreds of kilometers are related to spatial variability in the ocean. In this study, local and integrated upstream satellite-derived rain accumulation are compared to the horizontal variability of vertical gradients of temperature and salinity measured between the surface, 2 m, 3 m, and 5 m during the 2016 SPURS-2 experiment in the eastern Pacific Ocean.
Lee, T. (20-Sep-17). Aquarius Version 4.61 QL is an instrument-based calibration that does not rely on HYCOM or Argo as a global reference and is compared to V6.61, with the goal of determining whether the V4.6QL should be included in the Version 5 release.
Reagan, J., Boyer, T., and Antonov, J. (13-Nov-13). Aquarius level-3 monthly sea surface salinity (SSS) fields are compared to the World Ocean Database (WOD) derived SSS fields from September 2011 through June 2013. The datasets compare very well to one another outside of regions with large freshwater fluxes, high latitudes, and coastal regions. Annual cycles also compare very well.
Reagan, J.R., Boyer, T.P. and Antonov, J.I. (26-Feb-14). The Aquarius level-3 monthly sea surface salinity (SSS) fields are compared to the World Ocean Database derived SSS fields from September 2011 through December 2013.
Reagan, J., Boyer, T., Antonov, J., and Zweng, M. (12-Nov-14). A new monthly sea surface salinity (SSS) product calculated from profile data within the World Ocean Database is compared and contrasted with Aquarius SSS, both standard and Combined Active-Passive products, from September 2011 through September 2013.
Williams, G., Zaidman, P., Glembocki, N., González, R., Esteves, J., Narvarte, M, and Gagliardini, D. (12-Nov-13). In situ records of sea surface temperature collected between 2005 and 2009 were used to compare, for the first time, the temperature estimated by the Multichannel algorithms (MCSST) of the Advanced Very High Resolution Radiometer (AVHRR) sensors in San Matías Gulf (SMG), in the north of the Argentine Patagonian Continental Shelf. This study may be considered as a basis to make comparisons in future studies involving NIRST temperatures and in situ records in SMG.
Dinnat, E.P., Le Vine, D.M., Abraham, S., de Matthaeis, P., and Utku, C. (28-Sep-15). Spaceborne radiometric measurements at L-band from the Aquarius instrument are compared to numerical model simulation. Measurements/model comparisons are also performed to assess the uncertainty of various aspects of the data processing that are critical for retrieving Sea Surface Salinity, such as the correction for Faraday rotation and the impact of sea surface roughness on the surface signal.
Dinnat, E. (15-Nov-11). Comparisons of measured antenna temperatures and simulated ones to assess calibration bias over ocean scenes, calibration drift over ocean scenes, and calibration over cold sky.
Dinnat, E.P., Abraham, S., Le Vine, D.M., de Matthaeis, P., and Utku, C. (28-Sep-15). It is shown how the Aquarius spaceborne radiometric instrument is calibrated for different atmospheric conditions like temperature and wind speed.
Drucker, R. and Riser, S. (16-Apr-13). We compared Aquarius level-2 V1.3.9 sea surface salinities (SSS) with near-surface salinities from Argo floats for a period of 15 months. For this period, near-surface salinites were collected from all delayed-mode Argo profiles worldwide. Approximately 11,000 profiles occurred within the Aquarius footprint within ±24 hours of acquisition. After filtering for various contaminations, approximately 8700 data pairs remained for direct comparison. Results and conclusions from these comparisons will be presented.
Mannshardt, E., Sucic, K., Fuentes, M., and Bingham, F. (11-Nov-14). Using Argo in situ and Aquarius version 3.0 sea surface salinity, we compare measured salinity across metric distributions.
Soldo, Y., de Matthaeis, P., Le Vine, D., and Richaume, P. (11-Nov-14). The ESA (European Space Agency) SMOS (Soil Moisture and Ocean Salinity) satellite and the NASA (National Aeronautics and Space Administration) Aquarius instrument have been measuring Earth's natural emissions in the protected part of the L-band (1400-1427 MHz) since January 2010 and August 2011, respectively. In this work, the regulations, both instruments see the quality of their observations degraded by significant Radio (RFI) contamination in both instruments have been compared through the "RFI probability" associated to points on Earth's surface, i.e. the ratio between the number of times RFI were detected on a certain point and the number of times the same point was observed.
Ren, L. and Bayler, E. (11-Nov-14). Comparing sea-surface salinity observations from the U.S. National Aeronautics and Space Agency's (NASA) Aquarius mission and in-situ Argo float data at global, zonal and regional scales reveals interesting and unexpected insights on data quality and uncertainty.
Manaster, A., Meissner, T., and Wentz, F. (17-Jan-17). Two reference salinity models – Hybrid Coordinate Ocean Model (HYCOM) and Forecast Ocean Assimilation Model (FOAM) – were compared with Argo buoy data, considered to be the “truth” for this study. The purpose of this study is assessing the accuracy of the Aquarius-derived dataset, which presently uses HYCOM as its reference salinity. One outcome may be replacing HYCOM with Argo as the Aquarius reference salinity in some regions, if not globally.
Dinnat, E., Le Vine, D., Meissner, T., Boutin, J., and Martin, N. (11-Apr-16). Our presentation will report comparisons between SSS retrieved by SMOS and Aquarius, and comparisons between satellite SSS and in situ measurements. We will discuss the impact of the latest changes in the SMOS and Aquarius processing on the retrieved SSS and the differences between both instruments. The impact of differences in the retrieval algorithms (e.g. dielectric constant, ancillary sea surface temperature, surface roughness model, Faraday rotation) on the differences in SSS will be analyzed. If the maturity of the SSS retrieval algorithm for SMAP permits, we will also report first comparisons of SMAP SSS with other satellite SSS and in situ data.
Presented at the 2016 AGU Fall Meeting
Susanto, R.D., Setiawan, A., Zheng, Q., Sulistyo, B., Adi, T.R., Agustiadi, T., Treggono, M., Triyono, T., and Kuswardani, A. (16-Dec-16). The seasonal variability of a full lifetime of Aquarius sea surface salinity time series from August 25, 2011 to June 7, 2015 is compared to salinity time series obtained from in situ observations in the Karimata Strait. The Karimata Strait plays dual roles in water exchange between the Pacific and the Indian Ocean. The salinity in the Karimata Strait is strongly affected by seasonal monsoon winds. During the boreal winter monsoon, northwesterly winds draws low salinity water from the South China Sea into the Java Sea and at the same time, the Java Sea receives an influx of the Indian Ocean water via the Sunda Strait.
Lagerloef, G. (31-Oct-12). A review of Aquarius-retrieved salnity as compared to salnity from Argo buoys, from August 2011-October 2012.
Lang, R., Zhou, Y., Dinnat, E., and Le Vine, D. (18-Jan-17). Seawater dielectric constant measurements (32 data points) have been used to determine the “GW” model function, based on varying temperature and salinity. This is compared with previous model functions, Klein-Swift and Meissner-Wentz over temperature ranges from 0 to 35 degrees C and salinity values of 30, 33, 35, and 38. Each of these is also compared with Argo buoy data whose SSS sampling SSS is mainly from 34 to 36. Future work will make more measurements in this range to improve the GW model function’s accuracy.
Wentz, F. and Meissner, T. (31-Mar-15). This presentation focuses on the Aquarius algorithm tables, including an overview of tables affected by land, sun and galactic contributions. The regenerated tables using the new antenna pattern and galaxy map are shown in comparison to their previous versions, and the impact of these updates is reviewed.
Ghazi, Z., Jones, L., and Jacob, M.M. (13-Nov-13). The MWR Calibration Team has developed an improved Microwave Radiometer (MWR) algorithm (version 6) to convert the radiometric counts to brightness temperature (Tb). This algorithm is based upon rigorous radiative transfer models with empirically derived coefficients from both pre-launch thermal vacuum radiometric calibration testing and on orbit intersatellite cross calibrations (XCAL) with the Naval Research Lab's WindSat satellite radiometer. This presentation reveals recent results of on-orbit MWR/WindSat XCAL comparisons for the newest version 6 of the MWR counts to Tb algorithm, which includes a "counts linearization" procedure to correct for a small radiometer non-linearity.
Jones, L., Ghazi, Z., Jacob, M., and Santos-Garcia, A. (11-Nov-14). The Central Florida Remote Sensing Lab, in collaboration with CONAE, have developed two improved algorithms to convert the radiometric counts to brightness temperature for production of MWR level-1 science data. This poster presents a description of these algorithms and shows results for MWR Cal/Val activities during the past 15 months.
Ghazi, Z., Santos-Garcia, A., Jacob, M.M., and Jones, L. (10-Sep-15). This paper presents the brightness temperature algorithm and on orbit validation for the newest version (V6.0), which includes a radiometer system non-linearity correction.
Jones, L., Ghazi, Z., Jacob, M.M., Santos-Garcia, A., and Bruscantini, C. (30-Nov-17). The Central Florida Remote Sensing Lab (CFRSL), in collaboration with CONAE, have developed two improved algorithms to convert the radiometric counts to brightness temperature (Tb) for production of MWR level-1 science data. This poster presents a description of these algorithms and shows results for MWR Cal/Val activities during the past 15 months.
Marenchino, M. and Bruno, L. (11-Apr-12). Overview of the CONAE data archival system, including: post-launch and nominal working processes; status of data processing and distribution; priorities; and products.
Eriksen, C.C. (26-Feb-14). It has long been recognized that ocean salinity estimates made from in situ conductivity-temperature-depth (CTD) instruments depend for accuracy on correction of sample temperature for thermal exchange across conductivity cells.
Presented at the 2014 AGU Fall Meeting
Douglass, E. and Richman, J. (18-Dec-14). In a preliminary step toward assimilation of Aquarius data, observed sea surface salinity is compared with modeled sea surface salinity.
Lee, T. (29-Mar-16). The mission target accuracy of Aquarius SSS of 0.2 psu on a monthly time scale and a 150-km spatial scale includes time, mean and temporal variations. It does not isolate Aquarius' ability to characterize temporal changes on various space and time scales, which is more fundamental to science requirements. This presentation focuses on evaluating the consistencies of Aquarius V4 monthly gridded SSS using two Argo monthly gridded products on different space and time scales, and contrasts these consistencies with those between two Argo products.
Presented at the 2016 AGU Fall Meeting
Lee, T. (16-Dec-16). Understanding the accuracies of satellite-derived sea surface salinity (SSS) measurements in depicting temporal changes and the dependence of the accuracies on spatio-temporal scales are important to applications, capability assessment, and future mission design. This study quantifies the consistency between Aquarius Version-4 monthly gridded SSS (released in October 2015) with two widely used Argo monthly gridded near-surface salinity products.
Lee, T. (25-Apr-17). Understanding the accuracies of satellite-derived sea surface salinity (SSS) measurements in depicting temporal changes and the dependence of the accuracies on spatiotemporal scales are important to capability assessment, future mission design, and applications to study oceanic phenomena of different spatiotemporal scales. This study quantifies the consistency between Aquarius Version-4 monthly gridded SSS (released in late 2015) with two widely used Argo monthly gridded near-surface salinity products.
Meissner, T., Wentz, F.J., Manaster, A., and Lindsley, R. (12-Feb-18). The Aquarius Version 5.0 release in late 2017 has achieved an excellent level of accuracy and significantly mitigated most of the regional and seasonal biases that had been observed in prior releases. The SMAP NASA/RSS Version 2.0 release does not quite yet reach that level of accuracy. Our presentation discusses the necessary steps that need to be undertaken in the upcoming V 3.0 of the SMAP salinity retrieval algorithm to achieve a seamless transition between the salinity products from the two instruments. We also discuss where fundamental differences in the sensors make it difficult to reach complete consistency.
Vinogradova, N.T., Ponte, R.M., Fukumori, I., and Wang, O. (26-Feb-14). Linking information from sea surface salinity (SSS) to the amount of freshwater that leaves or enters the ocean via evaporation, precipitation, and runoff (FWF), can improve our understanding of the global hydrological cycle, but the problem is challenging because the relationship between SSS and FWF can depend on complex upper-ocean dynamic processes. One way around this issue is to efficiently combine information from SSS measurements with dynamical and physical constraints of ocean models.
Presented at the 2016 AGU Fall Meeting
Vinogradova, N.T. and Ponte, R.M. (16-Dec-16). To understand the ongoing alteration of the Earth’s water budget, it is essential to assess the variability of its oceanic constituent as this component supplies more than 75% of the evaporated and precipitated water in the global water cycle. Here we examine the change in the ocean water cycle and the ocean's response to such changes over the contemporary, well-observed period spanning the last two decades. In particular, we focus on recent changes in surface salinity and fluxes of freshwater within the atmosphere-ocean-land-ice system.
Schanze, J., Kao, H-Y., Springer, S.R., Lagerloef, G.S.E., Carey, D., and Thompson, E.J. (27-Aug-18). Here, we present a brief update on ongoing salinity science and validation at Earth and Space Research. With the transition from Aquarius to SMAP, it is particularly important to understand the differences in how surface salinity features are observed by these radiometers to create a continuous salinity data record spanning seven years. Furthermore, regular validation of SMAP is crucial to understand limitations and advances in the retrieval algorithms, and to assess the quality of the observations.
Farrar, J.T., Rainville, L., Shcherbina, A., Plueddemann, A.J., Hodges, B., Schmitt, R.W., Kessler, W.S., Riser, S., and Edson, J.B. (12-Feb-18). The Salinity Processes in the Upper-ocean Regional Study (SPURS) was a two-part field campaign focused on understanding the physical processes affecting the evolution of upper-ocean salinity: SPURS1 focused on the region of climatological maximum sea surface salinity in the subtropical North Atlantic, and SPURS2 focused on the high-precipitation region of the northeastern tropical Pacific Inter-tropical Convergence Zone.
Farrar, T., Rainville, L., Plueddemann, A., Kessler, B., Lee, C., Hodges, B., Schmitt, R., Riser, S., Edson, J., Eriksen, C., and Fratantoni, D. (12-Mar-18). The authors describe the SPURS-1 and SPURS-2 measurement programs, which included heavily instrumented air-sea interaction moorings and a dense array of measurements from moorings, Argo floats, gliders, and satellites.
Serafini, M.C. (17-Nov-15). Contribution from the SAC-D/Aquarius Observatory for a Better Understanding of Environmental Variables
Tranchant, B. (12-Feb-18). An ESA project was set up in October 2016 aimed at assessing the impact of satellite sea surface salinity (SSS) data assimilation on analyses/forecasts of the 2015/16 El Niño event. To improve the uptake and use of SSS data for ocean forecasting this project is designing and performing Observing System Experiments (OSEs) of SSS using ocean modelling and assimilation systems.
Kilic, L., Prigent, C., Aires, F., Boutin, J., Heygster, G., Donlon, C., and the CIMR Team (09-Nov-18). The Copernicus Imaging Microwave Radiometer (CIMR) mission is a high priority candidate mission within the European Copernicus Expansion program for all-weather, high spatial resolution and accurate estimation of ocean and sea-ice parameters. The conically scanning microwave radiometer imager includes channels at 1.4, 6.9, 10.65, 18.7, and 36.5 GHz and will operate in a Sun-synchronous polar orbit to provide sea surface temperature, sea ice concentration, sea surface salinity, ocean wind speed, and sea ice thickness on a sub-daily coverage.
Zanina A., Ciancio V., Morfino P., and Di Giovan, G. (14-Nov-13). This presentation looks at (1) cosmic-solar radiation in Antarctica (preliminary results show evidence for an environmental radiation intensity of about 1.4 mSv/year); (2) the breast cancer risk in airline cabin attendants; and (3) radiation measurements at Marambio Base.
Wentz., F., Meissner, T., and Manaster, A. (29-Apr-19). Issues with land contamination in Version 3 Remote Sensing Systems (RSS) processing – for both 70-km and 40-km products – are presented, followed by solutions to be applied in upcoming Version 4 data.
Yueh, S., Tang, W., Fore, A., Hayashi, A., Lee, T., Bindlish, R., and Jackson, T. (28-Nov-14). Aquarius is a combined passive/active L-band microwave instrument developed to map the sea surface salinity (SSS) field from space. The accuracy of Aquarius monthly averaged SSS product derived from the Combined Active and Passive (CAP) algorithm has been estimated to be about 0.1 to 0.2 psu Root-Mean-Square (RMS) between 40 degrees N and 40 degrees S through comparison with the Argo gridded dataset produced by the Asia-Pacific Data- Research Center (APDRC) and tropical moorings. We find that the regions with larger discrepancy include the ITCZ and near the outflow of major rivers, such as the Ganges, where the surface stratification due to precipitation or river discharge appears to be playing a significant role.
Presented at the 2018 AGU Fall Meeting
Gozdz, O., Buckley, M.W., and Shiffer, N.V. (14-Dec-18). Recently there has been intense debate about the relative roles of external forcing, stochastic atmospheric variability, and ocean dynamics (e.g., the AMOC) in the Atlantic Multidecadal Variability (AMV). While sea surface temperature (SST) variability has been well-studied, analysis of sea surface salinity (SSS) has received less attention. It is compelling to address SSS variability and its relation to the AMV because covariability between temperature and salinity (e.g. warm and salty or cool and fresh) is thought to be a signature of ocean dynamics. We investigate the covariability between temperature and salinity in the North Atlantic in several ocean reanalysis products.
Shcherbina, A.Y. and D'Asaro, E.A. (27-Feb-14). The evolution of the upper ocean thermohaline structure was observed with Mixed Layer Lagrangian Floats (MLFs) during the NASA Salinity Processes in the Upper-Ocean Regional Study (SPURS).
Li, Z., Li, P., and Bingham, F. (12-Mar-18). This presentation examines how the ROM modeling and data assimilation system performs and what can be done with it.
Mercado, G. and Marinsek, S. (17-Nov-15). This two-part presentation focuses on the Data Collection Platform (DCS), which contains instruments for the on board observatory. The second portion of the talk focuses on the use of the DCS to monitor Antarctic glaciers in conjunction with ground-based data loggers.
Ramiondo, H. and Madero, F. (20-July-10). Presentation includes: data collection system overview and characteristics; science data; ground segment overview; and products.
Sager, G.E., Carlotto, J.A., Juarez, J.M., and Mercado, G. (11-Apr-12). Overview of SAC-D Data Collection System (DCS) concludes: DCS was turned on for the first time on 31-Aug-11; during months of commissioning, it was subject of many in-orbit tests to assess functionality and performance; tests were performed involving different transmission and reception modes, operational frequencies and parameter adjustments; and DCS is fully functional and ready to collect enviromental data.
Rivas, R., Niclòs, R., García-Santos, V., Doña, C., Valor, E., Holzman, M., Bayala, M., Carmona, F., Ocamp, D., Thibeault, M., and Soldano, A. (12-Nov-13). A validation campaign was carried out to evaluate the SMOS-MIRAS Soil Moisture (SM) SML2UDP product (v5.51) in the Pampean Region of Argentina.
Presented at the 2016 AGU Fall Meeting
Subrahmanyam, B. and Melzer, B.A. (16-Dec-16). Global salinity data from Simple Ocean Data Assimilation (SODA) reanalysis highlights surface and subsurface ocean salinity trends in evaporative-dominated subtropical gyre systems over the period of 1950–2010. The SODA reanalysis provides an assimilated view of interannual and decadal salinity variability in the oceans. Subtropical sea surface salinity trends over the past six decades were analyzed, as salinity can be a potential diagnostic of the acceleration pattern of the global water cycle. Our results indicate an increase in salinity within subtropical gyre systems, although our trend is more conservative than previous estimates.
Friedman, A.R., Reverdin, G., Chafik, L., Holliday, N.P., Szekely, T., Valdimarsson, H., and Yashayaev, I. (08-Nov-18). Sea Surface Salinity integrates evaporation, precipitation and runoff. Together, salinity and temperature determine density, driving ocean circulation. The North Atlantic Subpolar Gyre is particularly important for vertical exchange and deepwater formation, and may influence the Atlantic meridional overturning circulation (AMOC). Presented here is a long-term dataset of North Atlantic SSS, SST and surface density from 1896-2015 known as BINS. BINS generally compares favorably with hydrographic profiles and gridded datasets, with some exceptions. BINS is able to resolve small-scale patterns, including the freshening in the central Subpolar Gyre and Labrador Sea, and warming in the Gulf Stream extension. Interannual variability was found to be greatest in the Labrador sea, where the contribution of salinity to density variability is the strongest.
Misra, S., Bosch-Lluis, J., Latham, B., Felten, C., Ogut, M., Brown, S., Lee, T., and Yueh, S. (09-Nov-18). The technology needs for a future salinity mission require wider bandwidths, spectrometer capabilities, multi-functionality, and multi bands. In this presentation, the authors look to raise technology levels and concepts by demonstrating 1) a satellite-based, real-time RFI processing capability to detect and remove unwanted RFI signals (CubeRRT), 2) a multi-functional / multi-band system, and 3) the feasibility of wide-band operation.
Presented at the 2012 AGU Fall Meeting
Font, J., Sabia, R., Ballabrera, J., Lagerloef, G. S. E., Bayler, E.J., Talone, M., Chao, Y., Donlon, C.J., and Fernandez-Prieto, D. (03-Dec-12). A preliminary attempt of deriving a purely satellite-based Temperature-Salinity diagram is presented, with the overall aim of assessing to what extent is possible, and in which geographical areas, to identify and trace water masses by satellite.
Sabia, R., Ballabrera, J., Lagerloef, G., Bayler, E., Talone, M., Chao, Y., Donlon, C., Fernandez-Prieto, D., and Font, J. (28-Sep-15). A preliminary attempt of deriving a purely satellite-based Temperature-Salinity (T-S) diagram is presented, with the overall aim of assessing to what extent is possible, and in which geographical areas, to identify and trace water masses by satellite.
Presented at the 2016 AGU Fall Meeting
Poague, J. and Stine, A. (16-Dec-16). Global warming is expected to intensify the global hydrological cycle, but significant regional differences exist in the predicted response. The proposed zonal mean thermodynamic response is enhanced horizontal moisture transport associated with increased saturation vapor pressure, which in turn drives additional net precipitation in the tropics and at high latitudes and additional net evaporation in the subtropics. Sea surface salinity (SSS) anomalies are forced from above by changes in evaporation minus precipitation (E-P) and thus will respond to changes in the global hydrological cycle, opening the possibility of using historical SSS anomalies to diagnose the response of the hydrological cycle to warming.
Tang, W., Yueh, S.H., Liu, W.T., Fore, A., and Hayashi, A. (24-Feb-16). This study aims to identify the influence of ocean processes on the freshwater exchange between air-sea interfaces, using Aquarius sea surface salinity.
Presented at the 2018 AGU Fall Meeting
Sahasrabhojanee, A., Ummenhofer, C., Li, L., and Schmitt, R.W. (12-Dec-18). When water evaporates from the oceans, it causes an increase in the Sea Surface Salinity (SSS). A significant portion of this evaporated water precipitates onto land. This provides a solid connection between change in Sea Surface Salinity and precipitation on land. Currently, it is more typical to use Sea Surface Temperature (SST) as a predictor for land precipitation. SSS is rarely included as a predictor because anomalies in SSS and in SST are often highly correlated and caused partially by the same phenomena, resulting in multicollinearity in the model.
Bindlish, R., Jackson, T., Zhao, T., Cosh, M., Holmes, T., and O'Neill, P. (30-Jan-13). Summary: Our approach to soil moisture retrieval uses the SCA with NCEP LST and MODIS NDVI climatology; we are working with ADPS to implement the Aquarius soil moisture algorithm; the use of the scatterometer to parameterize vegetation will be investigated; and the use of MWR to compute LST will be investigated.
Presented at the 2018 AGU Fall Meeting
Zhang, Y., Zhao, X., and Zhang, H-M. (10-Dec-18). As an effort to monitor the NOAA satellite oceanographic products (e.g., NOAA OSTM/Jason-2 and Jason-3 sea level anomaly, SAR ocean surface wind, SST, etc.) served at the NOAA National Centers for Environmental Information (NCEI), we have developed a real-time data quality monitoring system (DQMS) and services for these datasets. The principle concept of the DQMS is to calculate the data quality descriptive statistics for selected parameters as the data files are received at NCEI, along with near-real-time generation of the level-3 quick-look gridded data directly from the level-2 orbit data.
Lago, V., Durack, P., Wijffels, S., Bindoff, N., and Marsland, S. (26-Feb-14). Previous works have reported coherent and detectable changes to the ocean's subsurface salinity and temperature fields in response to observed climate change. Using idealized ocean model simulations, we investigate the role of surface water cycle (evaporation minus precipitation [E-P]) and temperature changes on subsurface ocean properties.
Chmelewski, M., Brown, J., Bingham, F., and Chkrebtii, O. (30-Apr-19). SPURS-1 central mooring data are statistically analyzed to create a curve of overall distribution of annual rainfall as a function of rain rate. When compared with exponential curves from other regions, there was a consistent finding that greater than 50% of each buoy's cumulative annual rain occurs during fewer than 8% of rain events.
Boutin, J.J., Vergely, J.L., Waldteufel P., Spurgeon, P., Dinnat, E., and Zhou, Y. (23-May-17). In this poster, we compare information on the dielectric constant retrieved from the angular variation of SMOS brightness temperatures with Klein and Swift (1977) and Meissner and Wentz (2012) models and with interpolated Lang measurements.
Boutin, J., Vergely, J.L., Waldteufel, P., Spurgeon, P., Dinnat, E., Zhou, Y. (20-Sep-17). Sea surface salinity (SSS) retrieved from L-band radiometry depends on the formulation chosen for modelling the dielectric constant of sea water. In this poster, the dielectric constant retrieved from SMOS brightness temperatures is compared with previous models.
Busecke, J. and Gordon, A. (27-Nov-14). The subtropical oceans all display relatively salty surface water, forming a regional sea surface salinity maximum (SSS-max), a response to the global hydrological cycle. Regional differences in basin SSS-max intensity and patterns complicate a direct comparison. We apply a methodology to compare the SSS-max regimes between oceans using a reference salinity based on the MIMOC climatology, eliminating the uncertainty due to an arbitrarily chosen isohaline for each ocean.
Hong, L. (01-Apr-15). In continuing efforts to validate Aquarius data, this talk focuses on the difference between forward modeled salinity data and those that have been retrieved by Aquarius.
Ueno, H. and Yasui, K. (26-Feb-14). In this study, the distribution and seasonal variation in the halocline in the world ocean were investigated using a simple halocline definition.
Presented at the 2014 AGU Fall Meeting
Ueno, H. and Yasui, K. (18-Dec-14). The distribution and seasonal variation in the halocline in the world ocean were investigated using a simple halocline definition.
Fine, E.C., Bryan, F.O., and Large, W.G. (26-Feb-14). In this study we quantify the expected range of diurnal salinity variations using a model developed for predicting diurnal sea surface temperature variations and search for regions where Aquarius may detect a true diurnal SSS signal.
Fine, E., Bryan, F., and Large, W. (11-Nov-14). In this study we quantify the expected range of diurnal salinity variations on a global scale using an extension of a model developed for predicting diurnal sea surface temperature variations. Based on this guidance, we search for regions where Aquarius may be detecting a true diurnal SSS signal. We also use an independent approach based on the near surface salinity balance and observed precipitation by isolating regions where the surface buoyancy input is such as to suppress vertical mixing. This study should help shed light on the processes contributing to upper ocean salinity variations, as well as provide a better target for assessing remaining errors in the Aquarius processing algorithms.
Skou, N., Kristensen, S., and Soebjaerg, S. (15-Apr-13). ESA's SMOS mission is faced with the challenging task of measuring the salinity of the oceans as well as the soil moisture over the continents, based on radiometric measurements of the natural emission from Earth. This is done using a microwave radiometer system operating in the protected radio astronomy band near 1.4 GHz (L-band).
Hauri, C., Truffer, M., Winsor, P., Dobbins, E.L., and Lennert, K. (26-Feb-14). To study the properties and circulation of the surface layer in Gotdthåbsfjord, western Greenland, and assess the drivers of the recent glacial acceleration and retreat, we deployed ice-reinforced satellite-tracked drifters in heavily ice-covered waters close to the glacier-ocean interface of the tidal outlet glacier Kangiata Nunata Semia. The drifters were equipped with temperature and salinity recorders located at 0, 7 and 15 m, and with a drogue at 20-m depth.
Durack, P.J., Gleckler, P.J., and Guilyardi, E. (25-Feb-16). Previous work has suggested that fresh ocean regions are becoming fresher, and salty regions saltier in part to a response to evaporation minus precipitation (E-P; water cycle) changes driven by a warming Earth. As long-term observational insights are limited, model simulations provide a novel method to assess and validate observed change estimates, and attribute the drivers of long-term change.
ten Doeschate, A. and Ward, B. (07-Nov-18). Rain can have a variety of effects on the ocean, including freshening of the surface, stratification of the near-surface layer, changing the heat and momentum fluxes, or changing the turbulent mixing properties of the near-surface layer. The vertical variability can be measured in high resolution with the Air-Sea Interaction Profiler (ASIP). A rain-induced near-surface stratification was observed by ASIP in the mid-latitude North Atlantic during a deployment in 2011.
Menezes, V. (23-May-17). Subtropical salinity maximum regions are particularly important because the salty subtropical underwater (STW) is formed by subduction of surface waters in these areas. In all oceans, the STW is transported equatorward from the formation region and are tightly related to the Subtropical-Tropical Cell. In the South Indian Ocean (SIO), the salinity maximum is further poleward (25S-38S) and eastward (60E-120E) compared to those in other oceans, and significantly impacts the circulation of the eastern basin.
Rainville, L., Drushka K., Eriksen, C., Farrar, T., Shcherbina, A., Thompson, E., Centurioni, L., Hormann, V., Hodges, B., and Schmitt, R. (24-May-17). The SPURS-2 field program aims to understand the structure and variability of upper-ocean salinity in the Eastern Tropical Pacific Ocean over more than one complete annual cycle. Since their deployments in August 2016, Seagliders have resolved salinity, temperature, density, and their lateral gradients, in the top 1000 m of the water column on horizontal scales of 20 km and time scales on the order of the inertial period in the central SPURS-2 region.
Meissner, T. and Wentz, F. (29-Jan-13). Conclusions include: 1-km land mask makes big improvement on sidelobe correction for islands; there is significant difference between sidelobe correction using scale model versus using GRASP; sidelobe correction is better than doing nothing; and there is significant room for improvement with better knowledge of antenna sidelobes.
Busecke, J.J.M., Abernathey, R.P., and Gordon, A.L. (24-Feb-16). Horizontal mixing by mesoscale eddies has been proposed to be a significant term of the mean surface freshwater budget in the North Atlantic sea surface salinity (SSS) maximum, balancing part of the excess evaporation in the subtropics. Here we present estimates of seasonal transformation rates in salinity coordinates due to mesoscale stirring.
Cassini, M.H. and Gomez, J.J. (17-Nov-15). Satellite information on climatic variables is very important in biodiversity conservation research because wildlife population density and distribution critically depends on the environmental and climatic conditions. The rapid and large-scale recording of climate factors provided by satellite platforms, allows for efficient monitoring of the impact of climate global change on biodiversity.
Zhou, Y., Lang, R., Utku, C., and Le Vine, D. (05-Dec-17). The accuracy of the George Washington University’s (GW) L-band cavity measurements of seawater is examined by measuring the effect of the capillary tube’s exit hole on the resonant frequency and by performing a theoretical study of the effect of cavity wall loss on the perturbation equations. The purpose of this study is to confirm the accuracy of past seawater measurements. GW has employed a cavity technique to determine the complex permittivity of seawater at L-band (1.413 GHz).
Dinnat, E., Boutin, J., Xiaobin, Y., and Le Vine, D. (13-Nov-14). ESA's Soil Moisture and Ocean Salinity (SMOS) and NASA's Aquarius use L-band (1.4 GHz) radiometers to measure emission from the sea surface and retrieve sea surface salinity (SSS). Significant differences in SSS retrieved by both sensors are observed, with SMOS SSS being generally lower than Aquarius SSS, except for very cold waters where SMOS SSS is the highest overall. Differences are mostly between -1 psu and +1 psu (psu, practical salinity unit), with a significant regional and latitudinal dependence. We investigate the impact of the vicarious calibration and retrieval algorithm used by both missions on these differences.
Clarke, A. and Zhang, X. (22-May-17). Fundamental to El Niño dynamics is the eastward movement of the western equatorial Pacific warm/fresh pool edge during El Niño and its westward movement during La Niña. Analysis of TAO/TRITON salinity and temperature measurements, as well as Aquarius sea surface salinity (SSS) and satellite altimetry, show that this zonal movement is mostly controlled by a shallow 23cm/s narrow jet.
Utku, C. and Le Vine, D.M. (10-Sep-15). A numerical reconstruction of the brightness temperature is examined as a potential way to improve the retrieval of salinity from Aquarius measurements closer to land-water boundaries. A test case using simulated ocean-land scenes suggest promise for the technique.
Presented at the 2012 AGU Fall Meeting
Ballabrera, J., Umbert, M., Hoareau, N., Turiel, A., and Font, J. (03-Dec-12). Until recently, the role of salinity observations in the operational simulation and prediction of ENSO was neglected because of the historical lack of observations and because leading intermediate coupled models had significant predictive skill without directly accounting for salinity effects.
Kao, H-Y. (31-Oct-12). Presented at the 2012 Aquarius Calibration/Validation Workshop at Goddard Space Flight Center.
Hoareau, N., Portabella, M., Lin, W., Ballabrera-Poy, J., and Turtle, A. (06-Nov-18). Satellite salinity measurements provide unprecedented spatiotemporal resolution / coverage as compared to any other observation system (Argo, CTD, TSG, moored buoys, etc.). This study focuses on the validation of SMOS-BEC and Aquarius v4 Level 3 products using triple collocation analysis.
Lang, R.H., Zhou, Y., Utku, C., and Le Vine, D. (17-Nov-11). The purpose of this research is to develop an accurate model for the dependence of the dielectric constant of seawater on temperature and salinity. The dielectric measurements should have an accuracy of 02% to meet the Aquarius goal of measuring salinity to an accuracy of 0.2 PSU.
Lagerloef, G. (20-July-10). Detailed overview of three phases of the Aquarius/SAC-D error validation and orbit corrections process: pre-launch (e.g., generating a special set of seven-day cycles to use in the operational mission simulator); in-orbit checkout, IOC (e.g., Aquarius commissioning phase timeline and approach, critical events and science tasks, etc.); and IOC plus six months (e.g., evaluating match-up data between Aquarius and in situ observing data).
Meissner, T., Wentz, F., Lagerloef, G., Le Vine, D., and Lee, T. (31-July-15). We present a method for formally assessing random and systematic uncertainties in the Aquarius salinity retrievals. The method is based on performing multiple retrievals by perturbing the various inputs to the retrieval algorithm.
Meissner, T., Wentz, F., and Lagerloef, G. (18-Nov-15). We present a method that allows for a realistic uncertainty assessment of the Aquarius salinity retrievals. This method involves modeling the errors of all input parameters that are ingested by the salinity retrieval algorithm. It also includes estimates for uncertainties due to contamination from land, sea ice and undetected RFI.
Melnichenko, O., Amores, A., Hacker, P.W., Maximenko, N.A., and Potemra, J.T. (12-Feb-18). Satellite altimetry, sea surface salinity (SSS) and Argo profile data are used to assess the importance of meridional eddy freshwater transport in the interiors of the subtropical gyres. In each of the five subtropical gyres, the role of mesoscale eddies is to pump freshwater into the gyre. The eddy freshwater transport is poleward on the equatorward side of the gyre and equatorward on the poleward side. There are marked differences between the oceans, however. For example, in the North Pacific, North Atlantic, and the South Indian Ocean, the eddy freshwater transport is equally important on both sides of the gyre, while in the South Pacific and the South Atlantic the poleward side dominates. There, the role of eddies is not only to pump freshwater into the gyre, but also to push the gyre center (determined as the SSS-maximum) equatorward.
Vinogradova, N. and Ponte, R. (17-Apr-13). One of the challenges in collecting and comparing satellite and in situ data is the mismatch in their spatial coverage and the depth of sampling. In this study, we quantify how much of a difference is expected between in situ and satellite measurements of sea-surface salinity (SSS) in the presence of small-scale horizontal variability and near-surface vertical stratification.
Presented at the 2014 AGU Fall Meeting
Woosley, R.J., Huang, F., and Millero, F.J. (18-Dec-14). The practical salinity (Sp), which is determined by the relationship of conductivity to the known proportions of the major components of seawater, and reference salinity (SR = (35.16504/35)*Sp), do not account for variations in physical properties such as density and enthalpy. Here, we combine the measurements of previous studies with new measurements for a total of 2,857 conductivity-density measurements covering all of the world's major oceans to derive empirical equations for the effect of silica and total alkalinity on the density and absolute salinity of the global oceans and recommend an equation applicable to most of the world oceans.
Presented at the 2016 AGU Fall Meeting
Ferster, B.S. and Subrahmanyam, B. (16-Dec-16). Since the 20th century, the Antarctic climate has been changing and relatively unstable. The Southern Ocean plays a major role in global ocean circulation. Because the Southern Ocean around Antarctica is the only location where the ocean can circulate freely all the way around the globe without continental barriers, it's a huge part of the ocean cycle. The use of salinity remote sensing technology offers spatial and temporal salinity observations than insitu and other conventional observations to better represent the sea surface salinity (SSS) in the Southern Ocean (SO). Using data sets from NASA’s Aquarius/SAC-D and ESA’s Soil Moisture and Ocean Salinity (SMOS), and NASA’s Soil Moisture Active and Passive (SMAP) we have estimated fresh and salt water fluxes.
Presented at the 2018 AGU Fall Meeting
Nichols, R.E. and Bulusu, S. (14-Dec-18). In recent decades we have seen major changes in Arctic Ocean circulation, salinity, and temperature and associated declines in sea ice coverage and mass balance. There is evidence of connections of these changes with climate indices, and the changes arguably affect climate by changing the radiative heat balance at high latitude, impacting the strength of the global overturning circulation.
Bartlett, J.T. and Subrahmanyam, B. (26-Feb-14). The launch of the Aquarius/SAC-D mission provided the ability to capture global sea surface salinity (SSS) variability. In this study, we examined the distribution of the Aquarius-derived SSS within the equatorial regions and subtropical gyres by comparing against the Soil Moisture and Ocean Salinity (SMOS) mission, Argo floats, and the Hybrid Coordinate Ocean Model.
Subrahmanyam, B., Felton, C., Murty, V., and Shriver, J. (11-Nov-14). Monthly barrier layer thickness (BLT) estimates are derived from satellite-derived salinity using a multilinear regression model (MRM) within the Indian Ocean. Sea surface salinity from the recently launched Soil Moisture and Ocean Salinity (SMOS) and Aquarius salinity missions are utilized to estimate the BLT. The MRM derived BLT estimates are compared to gridded Argo and Hybrid Coordinate Ocean Model BLTs.
Liu, C. and Shi, J. (31-July-15). Using time series Aquarius middle beam scatterometer observations, the two vegetation parameters C and D in water cloud model were estimated.
Vandemark, D. and Fent, H. (12-Apr-12). Presentation includes these early conclusions: Soil Moisture and Ocean Salinity (SMOS) sea surface salinity data able to produce before and after snapshots of plume location associated with tropical cyclone (TC) passage; satellite data yielding accurate sea surface salinity perturbation due to TC as compared to two Argo floats - 0.5 to 1.5 increase in sea surface salinity; and new look at plume - TC interaction with sea surface salinity + sea surface temperature perhaps allows enhanced diagnosis.
Vandemark, D. and Feng, H. (28-Mar-12). Presented at the 2012 Aquarius Calibration/Validation Workshop in Santa Rosa, CA.
Paget, A., Edson, J., and Clayson, C.A. (24-May-17). The upper ocean waters in the SPURS-2 region undergo an annual cycle of seasonal freshening. In particular, the October and November of 2016 are fresher than the previous years, and, even more striking, the salinity values during that period are nearly 1 PSU fresher than the previous years. This freshening is confirmed by Argo floats, the SPURS-2 Buoy, and SMAP observations. The goal of this work is to understand the reasons for this increased freshening in 2016.
Li, D., Zhao, T., Shi, J., Bindlish, R., Jackson, T., Peng, B., and Liu, Q. (09-Sep-15). In this paper the reliability of Aquarius level-2 soil moisture products is being validated by the Tibetan Plateau Soil Moisture/Temperature Monitoring Network and the Soil Climate Analysis Network.
Lee, T. (18-Sep-17). Comparison of Argo data to Aquarius data, with a focus on the comparison of L3 (EV)SCISM monthly SSS products with Argo monthly, 1 degree gridded maps.
Lee, T. (17-Jan-17). Presentation focuses on comparing various processing versions of Level-3 Aquarius sea surface salinity (SSS) products with monthly gridded maps of Argo buoy data from Scripps Institution of Oceanography (SIO). Analyses include: (1) Time-mean SSS differences; (2) Zonally-averaged and time-mean SSS; (3) Averages based on Argo latitudinal coverage; (4) Latitude-time plots of zonally averaged SSS with and without time mean; (5) Comparison of standard deviations at various spatial scales; and (6) Temporal standard deviations at various spatial scales. The study concludes that Version 4.5 has the smallest time-mean global, latitudinal, and regional biases while Version 4.0 has the smallest seasonal anomaly biases.
Champage, C., Rowlandson, T., Berg, A., Burns, T., L'Heureux, J., Adams, J., McNairn, H., and Toth, B. (09-Sep-15). Passive microwave derived satellite moisture data was evaluated over in Canada from two L-Band sensors. Soil moisture data from the Soil Moisture and Ocean Salinity (SMOS) and the Aquarius missino were used. This highlights the importance of distributed in situ networks.
de Matthaeis, P. and Le Vine, D. (15-Nov-11). The goal of this research is to identify regions adversely affected by radio frequency interference (RFI) and provide an analysis of the RFI flagging algorithm.
de Matthaeis, P., Le Vine, D., and Piepmeier, J. (27-Mar-12). The status of the radiometer RFI flagging algorithm performance are presented, as well as a status for what issues have already been addressed. The recently-discovered issue of short accumulations is investigated, and its potential for correction are discussed.
Abe, H. and Ebuchi, N. (13-Nov-13). The objective of this study was to validate SSS observed by Aquarius using various salinity data, including Argo observations.
Abe, H. and Ebuchi, N. (11-Nov-14). Sea surface salinity (SSS) fields from three different Aquarius products (Aquarius Official Release version 3.0 (V3.0), Combined Active-Passive (CAP) algorithm version 3.0, Remote Sensing Systems (RSS) test bed algorithm version 3) were evaluated by comparing them to in situ SSS measurements from Argo floats and tropical moored buoys, as well as with global gridded SSS fields produced by JAMSTEC and JMA/MRI. Level-2 Aquarius SSS was collocated with in situ near-surface salinity with spatial and temporal separations of less than 200 km and 12 hours, respectively.
Ebuchi, N. and Abe, H. (28-Sep-15). Sea surface salinity data derived from Aquarius on the SAC-D satellite were compared with observations by Argo floats in the global oceans to evaluate the quality of the Aquarius salinity measurement and assess the error structure in the data.
Abe, H. and Ebuchi, N. (17-Apr-13). Sea surface salinity (SSS) derived from the Aquarius and SMOS missions were validated using in-situ salinity data focusing on physical process around the sea surface. The Aquarius and SMOS SSSs were collocated with in-situ observations from Argo floats and offshore moored buoys and outputs from ocean optimal interpolation (OI) system and operational ocean assimilation system. In this abstract, results from the comparisons with observations by Argo floats and outputs from the OI system are reported.
Ebuchi, N. and Abe, H. (17-Sep-15). Sea surface salinity data derived from Aquarius and Soil Moisture and Ocean Salinity missions are being compared with observations by Argo floats in the global oceans and outputs from a global ocean data assimilation system.
Kim, S., Lee, J., and de Matthaeis, P. (12-Nov-14). This study demonstrates that the spaceborne Aquarius instrument is able to monitor the sea surface salinity variations in the East China Sea with the spatial resolution of about 150 km at 7-day interval, where routine observations are difficult.
Menezes, V.V. (29-Apr-19). Evaluation of four years of SMAP data (Remote Sensing Systems, RSS, Version 3 @ 70 km and 40 km; JPL Version 4.2) against Argo float measurements in the North Indian Ocean and Bay of Bengal. Conclusions include a fresh bias for RSS, salty bias for JPL, and better performance in the Arabian Sea than Bay of Bengal.
Dinnat, E. and Le Vine, D.M. (30-Apr-19). Sea surface salinity (SSS) products are compared to in-situ Argo data over two "eras": Aquarius (Sep 2011 to May 2015) and SMAP (Apr 2015 to Jun 2018). Results show very good performance for SMAP Remote Sensing Systems Version 3; however, some issues remain in Southern Ocean retrievals, uncertainties in the dielectric constant and atmospheric models, and contamination from land and ice.
Lee, T. (29-Apr-19). Monthly Level 3 (i.e., gridded) SMAP data are evaluated globally at three spatial scales with respect to gridded Argo data: 1x1 degree, 3x3 degrees, and 10x10 degrees. Statistical analysis of nearly four years of data from Remote Sensing Systems (Version 3 @ 70 km) and JPL (Version 4.2) show that SMAP Level 3 data approaches the accuracy of Aquarius Version 5 data.
Grings, F., Bruscantini, C., Carballo, F., Smucler, E., Perna, P., and Karszenbaum, H. (13-Nov-13). The objectives of this study are to (1) implement evaluation strategies of available course resolution for SM products; and (2) use these evaluation procedures to evaluate soil moisture products for the Pampas Plain (AMSR-E, and Aquarius).
Busecke, J., Gordon, A.L., Li, Z., Bingham, F.M., and Font, J. (27-Feb-14). The subtropical North Atlantic exhibits the saltiest surface waters of the open ocean, the sea surface salinity maximum (sss-max). Towed CTD measurements during the field program SPURS (March/April 2013) within the center of the sss-max reveal several fresh and warm anomalies, which deviate strongly from the climatological conditions in the sss-max.
Spurgeon, P. (16-Apr-13). Soon after launch it became clear there was a consistent and drifting mismatch between SMOS reconstructed L band sea surface temperatures (TBs) and Level 2 processor forward models, due to temporal changes in the instrument and Level 1 performance.
Rainville, L., Farrar, J.T., Lee, C., and Eriksen, C.C. (24-Feb-16). Observations collected during the Salinity Processes Upper-ocean Regional Study (SPURS) field campaign in the subtropical Atlantic Ocean are used to identify and quantify the processes responsible for deepening the surface mixed layer in Winter, and restratification in the Spring and Summer. We also present an overview of the upcoming SPURS-2 campaign in the eastern equatorial Pacific.
Vandemark, D., Fournier, S., Reul, N., Salisbury, J., and Chapron, B. (13-Nov-13). This study focuses on optimizing the combined use of ocean color satellite data and new ocean salinity measurements to better determine near surface salinity in regions with large freshwater outflow.
Fournier, S., Lee, T., Steele, M., Wang, X., Fukimoril, I., Kwok, R., and Wang, O. (09-Nov-18). Salinity observations are important to studying Arctic Ocean freshwater changes and transport, as well as ocean-ice interaction, and synergistic use of satellite observations can enhance monitoring of these changes. In this study, the authors compare three different sea surface salinity (SSS) products (BEC SMOS, JPL SMAP and REMSS SMAP), evaluate the extent to which satellite SSS can serve as a proxy for freshwater changes in the ice-free Arctic Ocean, and explore the potential of using sea surface height (from satellite altimetry) and ocean bottom pressure (from satellite gravimeter) to evaluate satellite SSS.
Reul, N., Alory, G., Maes, C., Illig, S., and Chapron, B. (17-Apr-13). The seasonal and interannual variability of the Sea Surface Salinity (SSS) deduced from SMOS and Aquarius-SAC-D satellite missions are analyzed over the period 2010-2012 in the Far Eastern Pacific Fresh Pool. The lowest values of salinity in surface layers (±33) in the tropical Pacific Ocean are found in this region of intense precipitation, associated with the northward migration of the Intertropical Convergence Zone (ITCZ) over Central America.
Soloviev, A.V., Dean, C.W., and McGauley, M. (12-Mar-18). The authors examine the fine-scale features of freshwater lenses, concluding that freshwater lenses (1) appear to act as a barrier to oil slick propagation and (2) are localized in thin, near-surface layers, sometimes less than 1m deep. Numerical simulations of freshwater lenses using computational fluid dynamics (CFD) tools in the framework of the CARTHE/GoMRI project continues.
Presented at the 2012 AGU Fall Meeting
Tauro, C.B., Hezain, Y., Etala, P., Echevarria, P., Jacob, M.M., and Jones, L. (04-Dec-12). CONAE, with the collaboration of CFRSL (Central Florida Remote Sensing Laboratory), are generating geophysical parameters, all over the sea surface, using brightness temperature measurements from MWR. These parameters include columnar water vapor, wind speed, sea ice concentration and rain rate, which are ancillary data for the Aquarius salinity measurements.
Tranchant, B., Grenier, E., Le Galloudec, O., and Lellouche, J.M. (30-Nov-17). In this study, we show that by assimilating Aquarius SSS data, a complementary information is brought. First results with the global 1/4° system show to what extent it should be possible to improve the meso-scale prediction and to correct sea surface salinity (SSS) bias.
Tauro, C., Masuelli, S., Salgado, H., Barreira, S., and Jones, L. (12-Apr-12). Overview includes: feasibility of determining sea ice concentration from Microwave Radiometer (MWR); NASA Team and CONAE algorithms; prototype steps; preliminary results from validation; and comparisons to National Snow and Ice Data Center results.
Meissner, T. (31-Mar-15). Physical measurements have values and uncertainty, and it is important for the ocean modeling (and other) communities to understand the sources of error in the salinity measurement from Aquarius. This presentation discusses the creation of an uncertainty estimate for Aquarius, and presents result for L2 and L3 uncertainty estimates.
Hasson, A.E., Delcroix, T., and Boutin, J. (26-Feb-14). This study investigates causes for the formation and the variability of the Sea Surface Salinity maximum (SSS>36) centered near 18°S-124°W in the South Pacific Ocean over the 1990-2011 period at the seasonal timescale and above.
Presented at the 2014 AGU Fall Meeting
Katsura, S., Oka, E., and Sato, K. (18-Dec-14). Formation mechanism of barrier layers in the subtropical Pacific was investigated by using Argo profiling float data and shipboard hydrographic section data.
Katsura, S. and Oka, E. (26-Feb-14). Formation mechanism of winter barrier layer and their properties in the subtropical regions in the North and South Pacific have been investigated using Argo profiling float data.
Drushka, K., Asher, B., Iyer, S., Thompson, E., Jessup, A., and Clark, D. (07-Nov-18). The Surface Salinity Profiler (SSP), sometimes referred to as a salinity snake, was used during the SPURS-2 cruise to quantify the instantaneous response of the ocean to rainfall. During the 2016 and 2017 SPURS-2 cruises, the SSP was deployed during approximately 40 rain events. This presentation illustrates the rain rate, wind speed, salinity and dissipation rate for several distinct rain events, and examines the relationship between existing stratification and the dissipation rate of rainfall events.
Zeng, L., Liu, W.T., Xue, H., Xiu, P., and Wang, D. (24-Feb-16). Newly available sea surface salinity (SSS) data from Aquarius together with in situ hydrographic data are used to explore the spatial and temporal characteristics of SSS in the South China Sea (SCS).
Presented at the 2014 AGU Fall Meeting
Zeng, L., Liu, W.T., Xue, H., Wang, D., and Xing, T. (18-Dec-14). Newly available sea surface salinity (SSS) data from the Aquarius together with in-situ hydrographic data are used to explore the spatial and temporal characteristics of SSS in the South China Sea.
Susanto, R. and Zheng, Q. (12-Nov-14). The proposed research is a pioneering work to determine the freshwater flux from the Bay of Bengal, the South China Sea, and the Eastern Indian Ocean and its impacts on the Indonesian Throughflow, using in situ observations and satellite data, especially the Aquarius/SAC-D satellite ocean salinity data.
Reul, N. (12-Feb-18). A number of weather systems can produce extreme rainfall over the ocean, including squall lines, mesoscale convective complexes, and tropical cyclones (TCs). Intense TCs generate extreme rainfall events with rain rates that can reach local values significantly greater than 45 mm/h, generally found in the vicinity of the storm inner core, but also at the storm's periphery within the spiraling rain bands (Houze, 2010). These events can last sometimes more than 72 hours with such high rain fall rates (Shepherd et al., 2007). Due to those typically very heavy rains associated with TC, the upper ocean salinity can be substantially freshened by those very large and intermittent fresh water flux into the ocean.
Presented at the 2018 AGU Fall Meeting
Dean, C. and Soloviev, A. (14-Dec-18). Convective rains and/or river runoff produce localized freshwater lenses in the near-surface layer of the ocean that have significant density anomalies and thus horizontal pressure gradients. As a result, these lenses can spread and propagate as gravity currents, interacting with wind stress. We have modeled freshwater lens dynamics in the near-surface layer of the ocean using computational fluid dynamics (CFD) tools.
Dean, C., Soloviev, A., and Helber, R.W. (24-Feb-16). Convective rains in tropical regions produce lenses of freshened water in the near surface layer of the ocean. These lenses are localized in space and typically involve both salinity and temperature anomalies. Dynamics of freshwater lenses can be linked to the formation of the barrier layer and fronts, thus influencing large scale processes and contributing to the salinity field in the Aquarius and SMOS satellite footprints.
Benetti, M., Reverdin, G., Pierre, C., and Kathiwala, S. (26-Feb-14). The freshwater budget in the subpolar gyre contributes to controlling the meridional overturning circulation variability. The measurement of the isotopic composition of sea water allows determination of the origin of the freshwater sources flowing in the supbolar gyre.
Kerr, Y., Cabot, F., Leroux, D., Rougé, B., and Albitar, A. (15-Apr-13). The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched in November 2009. This ESA led mission for Earth Observation is dedicated to provide soil moisture over continental surface (with an accuracy goal of 0.04 m3/m3) and ocean salinity. These two geophysical features are important as they control the energy balance between the surface and the atmosphere.
Presented at the 2016 AGU Fall Meeting
Yu, L. (16-Dec-16). Studies of recent years have led to an increasing recognition that the evaporation-minus-precipitation (E-P) flux and SSS are not directly linked but through oceanic processes. Two fundamental characteristics define the complex relationship between SSS and E-P. First, E-P is a mass flux and does not stay locally. For instance, when rain adds to the mass of the water column, it causes a pressure perturbation and fast oceanic responses in terms of gravity waves and barotropic Rossby waves. Secondly, E-P does not have a feedback relationship with SSS. This is in stark contrast to the surface heat flux which serves as both forcing and damping mechanisms for SST. E-P forces SSS anomalies but does not dampen them. As a consequence, SSS anomalies tend to be carried out by oceanic processes and circulate around for a period of time. Here we present the analysis of the ocean dynamical control on E-P generated SSS anomalies in two contrasting regimes.
Brown, S. (29-Mar-16). The history of Aquarius algorithm development from launch until present. V1.3 (August 2012) took into account initial post-launch adjustments. V2 (February 2013) covered spacecraft pointing calibrations, updated antenna patterns, drift corrections, and radio frequency interference (RFI) algorithm parameters. In V2, "wiggles" were included as an offset and the roughness correction was based on the NCEP model. V3 (June 2014) included updated antenna pattern coefficient (APC) parameters, a roughness correction based on scatterometer data and horizontally-polarized brightness temperature, empirical ascending/descending symmeterization, application of empirical sea surface temperature (SST) bias adjustments, and simplified drift correction. V4 (July 2015) included a hybrid antenna pattern to adjust excess spillover, updated empirical SST bias correction and non-linear Stokes parameter (I/Q) coupling.
Brown, S. (17-Jan-17). Presentation provides details on various Aquarius data processing releases over time. Version 1.3 was the first (August 2012) while Version 4 (July 2015) was the most recent public release. Each had ever-improving salinity retrievals with updates to antenna patterns, ocean roughness corrections, masks (e.g., RFI, land), and corrections for instrument drift and galaxy reflection off the ocean surface. Recent processing versions (i.e., 4.1 through 4.5) are also described; details of these are being evaluated by the Cal/Val team to determine which items should be included in the final release (Version 5).
Brown, S., Misra, S., Lee, T., and Yueh, S. (09-Nov-18). The future of NASA's L-band mission falls into competed programs, necessitating innovative designs to maintain continuity. In this presentation, the author looks at Salinity mission enhancements, which are realizable with recent technology advancements in areas such as spectral radiometry. Spectral measurements (0.6-3.0 GHz) would replace the single L-band channel and allow for unconstrained, simultaneous retrieval of sea surface temperature, sea surface salinity, and wind speed with the added benefits of dynamic spatial resolution, measurement of sea ice thickness in the range of 0-1m, deeper penetration into soil / vegetation for soil moisture measurements, and the detection and removal of RFI in space. Trade studies are also planned to evaluate concepts with program constraints: partnerships will likely be required. The incorporation of a spectrometer instrument into the CIMR observatory may be possible.
Brown, S., Misra, S., Lee, T., and Yueh, S. (30-Apr-19). Sea surface salinity was not included as an allocated "Flight Program Element" in the 2017 Decadal Survey and thus falls into the category of "competed programs" cost capped at $150M. Several options are presented to spark discussion on maintaining salinity continuity in the future.
Wentz, F. and Meissner, T. (18-Sep-17). This presentation provides an overview of the SMAP salinity instrument, the RSS SMAP Salinity Retrieval Algorithm, and compares SMAP salinity to data collected by Aquarius.
Hong, L., Gales, J., and Carey, D. (17-Jan-17). To assess specific components of Aquarius data processing, a series of evaluation products were developed from May 2015 through December 2016 (V4.1, V4.2, etc.). Major components include instrument corrections (i.e., “wiggles”), updated sea surface temperature source, galactic symmetrization, Rain Impact Model (RIM), along with new galaxy and oxygen models. An overview of these evaluation versions is presented, including analyses of their effects on salinity retrievals (i.e., time series graphs and maps).
Heredia, S.D., Masuelli, S., and Madero, F. (17-Nov-15). The SAC-D/Aquarius mission was designed to provide weekly global map of sea surface salinity. In this way the MWR has the capability to produce these weekly information for its retrieved geophysical variables.
Presented at the 2014 AGU Fall Meeting
Chandanpurkar, H.A., Reager, J.T., and Famiglietti1, J.S. (18-Dec-14). Sea surface salinity (SSS) is an effective indicator of global freshwater cycle. At the mixed layer, salinity is governed by the net freshwater flux from ocean evaporation (E), precipitation (P), and continental discharge, horizontal advection, and vertical mixing. Here, we use new SSS observations from Aquarius/SAC-D and SMOS, complimented by in situ observations from Argo floats, multiple satellite-based datasets for E and P, and modeled datasets to detect, isolate, and analyze the spatial and temporal patterns of discharge plumes from major rivers in the world.
Presented at the 2016 AGU Fall Meeting
Liu, T. and Schmitt, R.W. (16-Dec-16). Moisture transport from the excess of evaporation over precipitation in the global ocean drives terrestrial precipitation patterns. Sea surface salinity (SSS) is sensitive to changes in ocean evaporation and precipitation, and therefore, to changes in the global water cycle. We use the Met Office Hadley Centre EN4.2.0 SSS dataset to search for teleconnections between autumn-lead seasonal salinity signals and winter precipitation over the western United States.
Fine, R., Willey, D., and Millero, F. (11-Nov-14). The unprecedented salinity coverage from the Aquarius satellite (version 3) has provided the opportunity to calculate surface alkalinity globally. In the oceans, total alkalinity (TA) is a gauge on the ability of seawater to neutralize acids. Alkalinity is a major component of seawater, and there is a strong correlation between TA and salinity.
Fine, R., Willey, D., and Millero, F. (24-Feb-16). To document effects of ocean acidification it is important to have an understanding of the processes and parameters that influence alkalinity. Alkalinity is a gauge on the ability of seawater to neutralize acids. We use Aquarius satellite data, which allow unprecedented global mapping of surface total alkalinity as it correlates strongly with salinity and to a lesser extent with temperature.
Tang, W. (16-Nov-11). Results for the geophysical model function (GMF) for the radiometer, for both ascending and descending passes.
Tang, W. (17-Nov-11). An analysis of additional results for the geophysical model function on ascending and descending passes.
Umbert, M., Guimbard, S., Martinez, J., Ballabrera-Poy, J., and Turiel, A. (26-Feb-14). Thanks to new remote sensing platforms SMOS and Aquarius we have access to synoptic maps of Sea Surface Salinity (SSS). Much effort is still under way to bring both missions to meet pre-launch requirements on the quality of SSS. In this work we explain a new technique to improve the quality of SSS maps at Level 4, by combining SMOS/Aquarius data with high quality maps of Sea Surface Temperature.
Madero, F. (11-Apr-12). Presentation includes some known issues with the High Sensitivity Camera (HSC) such as: geolocation errors due to star tracker error from moon interference; and issues with generation of sun and moon position in Earth-Centered, Earth-Fixed (ECEF) reference frame.
Raimondo, H. and Marenchino, M. (11-Apr-12). Overview of radiometeric calibration of the High Sensitivity Camera (HSC), including: spectral and radiometric characterization; spectral response; relative and absolute calibration; and offset estimations.
Ramiondo, H. and Madero, F. (20-July-10). Presentation includes: High Sensitivity Camera overview and characteristics; definition of products and processing levels; information about the data processor; science and supplementary data; radiometric and geometric corrections; and product formats.
Melnichenko, O., Hacker, P., Maximenko, N., and Potemra, J. (26-Feb-14). A new gridded high-resolution sea surface salinity dataset has been developed at the University of Hawaii using Aquarius Level-2 data. The primary product is a weekly analysis on a nearly-global 0.5-degree grid for the period September 2011-present.
Presented at the 2018 AGU Fall Meeting
Liu, W.T. and Xie, X. (14-Dec-18). Ocean surface wind speed, sea surface temperature (SST), and integrated water vapor (W) have been derived, under clear and cloudy conditions, starting with Scanning Multichannel Microwave Radiometer (SMMR) on Seasat and Nimbus-7. The 1982-83 El Niño and Southern Oscillation episode initially escaped notice because it was obscured from spacebased visible and infrared sensors by volcanic aerosols. Nimbus-7 SMMR demonstrated for the first time the all-weather capability by monitoring the eastward migration of atmosphere convection and ocean warming along the equator during the episode. By deriving a statistical relation between W and near surface humidity, based on the coherence of vertical humidity profile, we pioneered the method of spacebased estimation of surface evaporation/latent heat flux, using bulk parameterization, in the 1980s.
Presented at the 2012 AGU Fall Meeting
Lagerloef, G.S.E., Kao, H-Y., Wentz, F.J., Le Vine, D.M., Yueh, S.H., and Feldman, G.C. (03-Dec-12). Aquarius satellite salinity measurements are resolving the major global and regional spatial patterns, and temporal variations, since the start of routine data collection on 25 August 2011. This description includes the principal seasonal variations over the first annual cycle as observed by the mission.
Thompson, E.J., Drushka, K., Asher, W., Jessup, A.T., Schanze, J.J., and Clark, D. (12-Feb-18). This study seeks to understand the impact of spatially and temporally varying rainfall on local salinity stratification. Previous observational studies have demonstrated a positive correlation between maximum salinity stratification and maximum rain rate when wind speed is constant. However, local rain rate and wind speed do not provide sufficient information to completely explain local salinity stratification measurements.
Hackert, E.C., Kovach, R.M., Busalacchi, A.J., Ballabrera-Poy, J., and Vernières, G. (12-Feb-18). In this presentation we assess the impact of satellite sea surface salinity (SSS) observations on seasonal to interannual variability of tropical Indo-Pacific Ocean dynamics as well as on dynamical ENSO forecasts. Our coupled model is composed of a primitive equation ocean model for the tropical Indo-Pacific region that is coupled with the global SPEEDY atmospheric model (Molteni, 2003; Kucharski et al., 2006).
Kovach, R.M., Hackert, E.C., Ballabrera-Poy, J., Busalacchi, A.J., Vernières, G., Molod, A., and Marshak, J. (12-Feb-18). In this presentation we assess the impact of satellite sea surface salinity (SSS) observations on dynamical ENSO forecasts for the big 2015 El Niño event. From March to June 2015, the unprecedented availability of two overlapping satellite SSS instruments, Aquarius and SMAP, allows a unique opportunity to compare and contrast forecasts generated with the benefit of these two satellite SSS observation types. We will present four distinct experiments for the overlap period that include 1) freely evolving SSS (i.e. no satellite SSS), 2) climatological SSS (i.e. WOA13 SSS), 3) Aquarius, and 4) SMAP initialization.
Tranchant, B., Remy, E., Greiner, E., and Legalloudec, O. (07-Nov-18). The objective of the SMOS NINO15 project was to assess and analyze the onset and evolution of the 2015-16 El Niño event. The work involved refining the Global Ocean Data Assimilation Experiment requirements for sea surface salinity after the analysis of the errors associated with the experiments. The work involved the production of a coordinated observing system experiment from two different operational global ocean forecasting systems by the use of SSS Bias correction and SSS data assimilation (including SMOS, Aquarius and SMAP data).
Brown, S. (30-Mar-16). This study assessed the dependence of atmospheric boundary layer stability on the excess emission generated by a rough ocean surface, one of the largest corrections required in the sea surface salinity retrieval algorithm. The difference in temperature between the air and sea is a measure of boundary layer stability, shown in previous work to be a key factor in air-sea interaction including wave and foam formation. Microwave sea surface excess emissivity has been shown to have a significant dependence on the air-sea temperature difference at C-band and higher, which might be the cause of the observed seasonal biases at high latitudes in Aquarius data. The model function developed for this study relates backscatter/emission as a function of wind speed, wind direction, sea surface temperature, significant wave height, polarization and incidence angle. Results show a strong correlation between salinity bias and air-sea temperature difference. The bias is suitable for an empirical correction but more work is needed to completely understand the physics.
Brown, S. and Misra, S. (11-Apr-16). The correction for wind-driven rough surface emission is one of the largest corrections that are required for satellite based sea surface salinity (SSS) retrieval. Missions such as SMOS, Aquarius and SMAP use models that describe the excess emission as a function of wind speed to remove this signal from the data in order to accurately estimate the sea water dielectric and hence SSS. Several studies have shown boundary layer stability is a key factor in air-sea interaction, including wave and foam formation and that wind speed alone may not be sufficient to describe the excess emission of the ocean.
Brown, S. (18-Nov-15). This study assesses the dependence of atmospheric boundary layer stability on the excess emission generated by the rough ocean surface. The correction for this excess emission is one of the largest corrections required in the retrieval algorithm for sea surface salinity.
Keerthi, M.G., Lengaigne, M., Vialard, J., and Benshilla, R. (07-Nov-18). Seasonal monsoons drive the climate of the Northern Indian Ocean. In the summer, there are strong southwesterly winds and heavy rainfall, and in the winter, there are cold and dry northeasterly winds with less precipitation. These seasonally reversing monsoon winds are responsible for reversing their circulation; the East Indian Coastal Current (EICC) flows either Northward or Southward. Horizontal salinity gradients were found to contribute up to 40% of the EICC intensity following the summer monsoon. Salinity gradients also enhance the mesoscale variability by up to 30% in the Western Bay of Bengal. The EICC was found to create conditions to form a freshwater "river in the sea" that creates a gradient that strengthens the EICC.
Presented at the 2016 AGU Fall Meeting
Chao, Y., Leiva, J., Farrara, J.D., Zhang, H. (16-Dec-16). A real-time California coastal ocean nowcast and forecast system is used to quantify the impact of river discharge on the California coastal ocean circulation and variability. River discharge and freshwater runoff is monitored by an extensive network of stream gages maintained through the U.S. Geological Survey, that offers archived stream flow records as well as real-time datasets. Of all the rivers monitored by the USGS, 25 empty into the Pacific Ocean and contribute a potential source of runoff data. Monthly averages for the current water year yield discharge estimates as high as 6,000 cubic meters per second of additional freshwater input into our present model.
Presented at the 2018 AGU Fall Meeting
Hackert, E.C., Kovach, R.M., Marshak, J., Borovikov, A., Molod, A., and Vernieres, G. (14-Dec-18). El Niño/Southern Oscillation (ENSO) has far reaching global climatic impacts and so extending useful ENSO forecasts would be of great benefit for society. However, one key variable that has yet to be fully exploited within coupled forecast systems is accurate estimation of near-surface ocean density. Satellite Sea surface salinity (SSS), combined with temperature, help to identify ocean density changes and associated mixing near the ocean surface. We assess the impact of satellite SSS observations for improving near-surface dynamics within ocean analyses and how these impact dynamical ENSO forecasts using the NASA GMAO Sub-seasonal to Seasonal (S2S Version 2) coupled forecast system (Molod et al. 2018 - i.e. NASA's contribution to the NMME project). For all initialization experiments, all available along-track absolute dynamic topography and in situ observations are assimilated using the LETKF scheme similar to Penny et al., 2013. A separate reanalysis additionally assimilates Aquarius V5 (September 2011 to June 2015) and SMAP V4 (March 2015 to present) along-track SSS data.
Presented at the 2012 AGU Fall Meeting
Hackert, E.C. and Busalacchi, A.J. (04-Dec-12). In earlier work we have demonstrated that assimilation of gridded fields of sea surface salinity (SSS), derived from in situ salinity observations, has led to significantly improved coupled forecasts for lead times greater than 6 months (Hackert et al., 2011). We found that the positive impact of SSS assimilation is brought about by surface freshening in the western Pacific that led to increased barrier layer thickness (BLT) and shallower mixed layer depth.
Presented at the 2014 AGU Fall Meeting
Busalacchi, A.J. and Hackert, E.C. (18-Dec-14). n this presentation we assess the impact of in situ and satellite sea surface salinity (SSS) observations on seasonal to interannual variability of tropical Indo-Pacific Ocean dynamics as well as on dynamical ENSO forecasts using a Hybrid Coupled Model (HCM) for 1993-2007 (cf., Hackert et al., 2011) and August 2011 until February 2014 (cf., Hackert et al., 2014).
Sun, J., Vecchi, G., Liao, E., Resplandy, L., and Soden, B. (30-Apr-19). Conditions associated with Tropical Cyclone Hudhud (2014) are examined in the Bay of Bengal including sea surface salinity (SSS) and temperature (SST), rainfall, wind, and radiation. Model and satellite data are used to compute mixed layer depth, leading to the conclusion that SST increased during low SSS, which provided favorable ocean conditions for storm intensification.
Presented at the 2016 AGU Fall Meeting
Kido, S. and Tozuka, T. (16-Dec-16). Sea surface salinity (SSS) in the tropical Indian Ocean undergoes large interannual variations associated with the Indian Ocean Dipole (IOD), but their impacts on the upper-ocean stratification and sea surface temperature (SST) are not fully understood. Here, using a 1-D turbulence closure model, a series of sensitivity experiments with and without salinity anomalies is carried out to quantify their impacts during positive IOD events.
Misra, S. and Brown, S. (29-Mar-16). An overview of the "wiggle correction" based on locking of the Aquarius voltage-to-frequency converter (VFC) locking was given. Each step of the correction implementation was described: (1) derive correction using difference between consecutive reference load count samples, (2) normalize mean correction to zero, (3) provide wiggle correction table with respect to reference load count, (4) use table to generate a time series for each channel, and (5) correct the reference load counts to calculate the antenna temperature. In conclusion, the wiggle correction has a zero bias with respect to the reference load and thus is not responsible for annual, seasonal, or other anomalous trends observed in the data.
Bayler, E., Osychny, V., Chawla, A., and Mehra, A. (23-May-17). The assimilation of sea-surface salinity (SSS) data into numerical prediction models serves to extract value from the observations, as well as integrates those observations with other data to produce an optimal output. Sea-surface salinity observations from the European Space Agency’s (ESA) Soil Moisture – Ocean Salinity (SMOS) mission and the National Aeronautics and Space Agency’s (NASA) Soil Moisture Active-Passive mission are now sufficiently mature for assimilation into NOAA’s operational models, in particular the Real-time Ocean Forecast System (RTOFS) and the Global Ocean Data Assimilation System (GODAS), the ocean component of NOAA’s operational Climate Forecast System (CFS).
Boutin, J., Vergely, J.L., Supply, A., Khvorostyanov, D., and Tarot, S. (27-Aug-18). Salinity observing satellites have the potential to monitor river fresh-water plumes mesoscale spatio-temporal variations better than any other observing system. In the case of the Soil Moisture and Ocean Salinity (SMOS) satellite mission, this capacity was hampered due to the contamination of SMOS data processing by strong land-sea emissivity contrasts. Based on the internal consistency of SMOS Sea Surface Salinity retrieved in various locations across swath, a correction was developed to mitigate SMOS systematic errors in the vicinity of continents and seasonally-varying latitudinal systematic errors (Boutin et al. 2018).
Skliris, N., Zika, J.D., Blaker, A., Nurser, G., Marsh, R., and Joey, S.A. (08-Nov-18). The conventional wisdom regarding the effect of warming on the water cycle is that wet areas may get wetter and the dry areas will be drier. This could lead to more drought and more floods. Salinity observations with high spatiotemporal coverage over the last decades offer a unique opportunity in terms of measuring the integrated effect of changes in the water cycle. Numerical simulations show that the surface salinity pattern amplifies substantially with anomalous surface warming. Approximately 45% of observed surface salinity pattern amplification over 1958-2017 can be explained by ocean warming and 15% by ice mass loss. The remaining signal (~40%) can be attributed to a water cycle amplification of 3.6% (±2.1) per degree of surface warming. There is potential for water cycle changes to be monitored using surface salinity observations if these surface warming effects are appropriately accounted for.
Dinnat, E.P. and Brucker, L. (23-July-17). We present a model to derive the ice fraction affecting observations by the Aquarius and SMAP radiometers and discuss the impact of different types of ice on observed brightness temperatures.
Dinnat, E. and Brucker, L. (18-Jan-17). The objective of this work is to provide improved sea ice fractions for the Level-2 Aquarius product. Data acquired near Antarctica using NOAA ice fractions show scattered and highly non-linear relationships with Aquarius brightness temperatures (Tb). Using the AMSR-2 Bootstrap Algorithm (ABA) largely reduces scattering and shows strong linearity with Aquarius Tb. Data plots from both hemispheres show good results with ABA; however, there are some issues related to multiyear ice in the northern hemisphere. The next step is empirical correction of Aquarius Tb for ice contamination to improve coastal sea surface salinity retrievals.
Presented at the 2012 AGU Fall Meeting
Jones, L., Hejazin, Y., and Rabollii, M. (03-Dec-12). The Aquarius/SAC-D sea surface salinity (SSS) measurement mission was launched into polar orbit during the summer of 2011. The prime sensor is a combined L-band radiometer/scatterometer developed jointly by NASA Goddard Space Flight Center and the Jet Propulsion Laboratory, which derives SSS from ocean surface brightness temperature measurements. This paper deals with a method of improving AQ SSS by making a making an ocean roughness brightness temperature correction.
Melnichenko, O. and Hacker, P. (30-Apr-19). Analysis of Remote Sensing Systems (RSS) Level 3 (i.e., gridded) sea surface salinity products @ 40 km and @ 70 km are presented over various regions. Also, optimally interpolated (OI) along-track RSS Level-2C non-resampled SMAP sea surface salinity data are presented from the Gulf of Mexico. The OI technique provides an opportunity to resolve features closer to coasts without noise issues found in the RSS 40 km product.
Presented at the 2014 AGU Fall Meeting
Mueller, C. and Xie, H. (18-Dec-14). With the Aquarius mission having completed its second full year of acquiring global sea surface salinity measurements, many corrections were accounted for and biases were removed. However, some biases remain, keeping the mission from achieving its goal of ±0.2 psu accuracy for monthly products (150 km pixel size). Uncertainties in the Southern Ocean (among other biases) not only keep the mission from attaining such accuracy globally, but it also forces continued reliance on in situ point data sources. A Python script package is developed to process the Level 2 data for use, allowing users to target specific variables and to prepare ship and buoy data for analysis with the Aquarius data.
Presented at the 2016 AGU Fall Meeting
Lagerloef, S.E. (16-Dec-16). To improve knowledge of the ocean surface salinity annual cycle, and its link to global precipitation patterns, remains a key science measurement objective for satellites. The Aquarius satellite data are applied here to address this, and the analysis is not as straightforward as it may seem. Sensor calibration is considered carefully to ensure that seasonality in external calibration data sources do not alias the satellite measurements. For example, quasi-monthly calibration error signals were identified early in the Aquarius mission.
Burgin, M. and van Zyl, J. (10-July-16). State of the art soil moisture radar retrieval algorithms traditionally depend on substantial amounts of ancillary data, such as land cover and soil texture/composition maps, to parametrize complex electromagnetic models. In this work, we pursue an existing empirical approach as an alternative; it expresses radar backscatter of a vegetated scene as a linear function of soil moisture, thus reducing the dependence on ancillary data. We use 2.5 years of L-band Aquarius radar and radiometer derived soil moisture data to determine the two unknowns of the linear model function on a global scale.
Kao, H-Y. (29-Mar-16). This presentation compared sea surface salinity (SSS) retrievals using NOAA Reynolds and the Canada Meteorological Center (CMC) sea surface temperatures (SSTs). It began with a comparison of Aquarius SSS data against Argo float matchups, which indicates that Aquarius SSS is biased high in the higher latitudes and low in the tropics. Time series plots for daily global average Aquarius (Beams 1, 2, 3) minus Argo SSS were shown along with histograms for Aquarius minus buoy differences. Overall, no obvious difference is found from the validation of SSS retrieval with different SST products. The same analysis was conducted for SSTs using Reynolds versus co-located buoy data and CMC versus co-located buoy data. SST from CMC shows smaller biases than Reynolds SST when comparing with in situ data, especially in low-mid latitudes. The last portion of the talk focused on the rain impact model (RIM) adjustment to Aquarius data.
Wang, Z., Boyer, T., Biddle, M., Zhang, H-M., and Bayler, E. (23-May-17). The newly developed NCEI Thermosalinograph Dataset (NCEI-TSG) is the world’s most extensive collection of uniformly-formatted, quality-controlled, thermosalinograph (TSG) data available without restriction. TSG data are in-situ high resolution measurements of sea surface salinity (SSS) and temperature (SST) from ships. Measurements of other oceanographic variables, such as oxygen, chlorophyll etc are often measured concurrently with sea surface salinity and temperature and included in the dataset.
Boyle, J.P. (12-Feb-18). In-situ 'near-surface' salinity data are presented as measured by an extremely small drifter buoy which was deployed in association with the Salinity Processes Upper-ocean Regional Study in the tropical Pacific (SPURS-2). This autonomous, wave-following buoy platform measures conductivity and temperature (~10 cm depth), sea state characteristics and near-surface water temperature (~2 cm depth).
Zhou, Y., Lang, R.H., Drego, C., Utku, C., and Le Vine, D. (28-Sep-15). The paper discusses the improved experimental methods used for the 2011-12 measurements of the dielectric constant of seawater. The new measurement data is also be compared with Klein-Swift (KS) model function and Meissner-Wentz (MW) model function.
Liu, W.T. and Xie, X. (18-Nov-15). Soil moisture and surface salinity from Aquarius are used to characterize the vagary of monsoon, from the pre-monsoon drought to the oceanic causes of monsoon onset. The river discharges, derived from altimeter and land surface models are compared and their effects on salinity distribution and on continental mass balance are examined.
Pablos, M., Piles, M., Gonzalez-Gambau, V., Camps, A., and Vall-llossera, M. (31-July-15). The Dome-C region, in the East Antarctic Plateau, has been used for calibration/validation of satellite microwave radiometers since the 1970's. However, its use as an independent external target has been recently questioned due to some spatial inhomogeneities found in L-band airborne and satellite observations. This work evidences the influence of the Antarctic ice thickness spatial variations on the measured SMOS and Aquarius brightness temperatures (TB).
Campos, E.J.D., Chidichimo, M.P., Garzoli, S., and Matano, R. (19-Nov-15). Results of numerical experiments with a 1/12-Degree, 32-layers ocean general circulation model are used to investigate impacts of interannual to interdecadal changes in the wind forcing on the circulation and meridional transports in the South Atlantic.
Kay, H-Y. and Lagerloef, G. (31-Mar-15). Researchers selected a track to examine the interbeam differences, using crossover differences to find the value of orbit errors. It remains clear what causes the interbeam differences, but the process used was determined to be useful in finding orbit errors and reducing interbeam differences.
Le Vine, D. (15-Apr-13). This working group aims toward a merged and validated data product. Initial work will concentrate on solving several key common geophysical modelling issues related to galaxy, roughness, emissivity, ascending-descending biases, RFI, etc., as well as direct inter-calibration of brightness temperatures and salinity products.
Bindish, R. (26-Mar-12). Aquarius observations compare well with SMOS observations. There is some scatter, possibly due to RFI in SMOS and Aquarius, as well as the heterogeneous footprint and different azimuth angles.
Bindlish, R., Jackson, T., and Zhao, T. (16-Nov-11). When comparing Aquarius and SMOS observations, it was found that Aquarius observations compare well with SMOS. There are differences in scatter due to RFI, heterogeneous footprint, and different azimuth angles between the two instruments.
Brown, S. and Misra, S. (27-Aug-18). In this talk, we will present results comparing residual systematic biases in SMAP to those that remained in the Aquarius V5 product. The aim is to identify common and non-common errors that will lead to a better understanding of their origin. Common errors can be traced to the processing algorithms and model functions, while non-common errors will have their origin in the individual instrument processing. We will analyze seasonal and regional biases over time. We will also present a detailed analysis of the noise in the SMAP product and the spatial correlation. Unlike Aquarius, SMAP is an imaging sensor. It is important to understand the spatial correlation of the noise that results from employing along track averaging of the calibration measurements as well as resampling the footprints. We will show the spatial correlation as a function of scale length which we expect to benefit future updates to the processing algorithms.
Blindish, R., Jackson, T., Peipmeier, J.R., Yueh, S., and Kerr, Y. (10-July-16). Verifying the calibration of the SMAP radiometer over land observations is an important mission requirement. Inter-comparison of L-band brightness temperature observations from different satellites (SMAP, SMOS and Aquarius) is a useful tool for radiometer calibration.
Pablos, M., Piles, M., Gonzalez-Gambau, V., Vall-Ilossera, M., and Camps, A. (15-Sep-15). The spectral window at L-band is a reserved wavelength that is used for the SMOS and Aquarius/SAC-D missions. Thus, these two missions are being compared to verify the continuity and consistency of the data.
Dinnat, E.P., Boutin, J., Yin, X., and Le Vine, D.M. (10-Sep-15). We assess the impact of the dielectric constant model and the ancillary sea surface salinity used by Aquarius and the Soil Moisture and Ocean Salinity (SMOS) missions for calibrating the radiometers and retrieving sea surface salinity.
Dinnat, E.P., Le Vine, D.M., Boutin, J., and Meissner, T. (27-Aug-18). We present comparisons between satellite sea surface salinity (SSS) products from the SMOS, Aquarius and SMAP missions and assess some of the possible reasons for the observed differences. We also compare satellite products to in situ observations. The comparisons focus on SSS large scale spatial patterns, temporal variability at regions of reference and statistical distribution. We also assess the dependence of SSS differences (between satellite products and between satellite and in situ) to sea surface temperature (SST), which has been an ongoing issue in the previous product versions.
Bulusu, S. (25-Apr-17). There is evidence that the global water cycle has been undergoing an intensification over several decades as a response to increasing atmospheric temperatures, particularly in regions with skewed evaporation - precipitation (E-P) patterns such as the oceanic subtropical gyres. Moreover, observational data (rain gauges, etc.) are quite sparse over such areas due to the inaccessibility of open ocean regions. In this work, a comparison of observational and model simulations are conducted to highlight the potential applications of satellite derived salinity from NASA Aquarius Salinity mission, NASA Soil Moisture and Ocean Salinity (SMOS), and ESA's Soil Moisture Active Passive (SMAP). We explored spatial and temporal salinity changes (and trends) in surface and subsurface in the oceanic subtropical gyres using Argo floats salinity data, Simple Ocean Data Assimilation (SODA) reanalysis, Estimating the Circulations & Climate of the Ocean GECCO (German ECCO) model simulations, and Hybrid Coordinate Ocean Model (HYCOM).
Melzer, B.A. and Subrahmanyam, B. (24-Feb-16). We studied the interannual and decadal variability of sea surface salinity variations in Oceanic subtopical Gyres using the Simple Ocean Data Assimilation reanalysis in five subtropical gyre locations from 1950-2010. Results indicated an average salinity increase of 0.12 psu in the subtropical gyres over the 61-year study, with the greatest increase occurring in the southern hemisphere gyres.
Grodsky, S., Johnson, B., Carton, J., and Bryan, F. (12-Nov-14). Aquarius sea surface salinity (SSS) reveals the presence of interannual salinity variations in the Caribbean with about 0.5 psu change between salty and fresh events. Anomalous SSS propagates westward across the basin at an average speed of 11 cm/s. Fresh and salty events in the Caribbean are preceded by corresponding SSS anomalies east of the Lesser Antilles.
Grodsky, S. and Carton, J. (23-May-17). The main mode of interannual near surface salinity in the tropical western Atlantic is related to ENSO teleconnections and is produced by changes in precipitation over the ocean and Amazon. The ocean rainfall has an almost immediate impact on underlying salinity in contrast to the land rainfall that leads to a delayed impact related to the hydrology of Amazon system. Due to the need for longer time records to resolve interannual signal, our investigation relies on historical syntheses of in-situ observations mainly focusing on the JAMSTEC analysis. The inferred patterns of variability are compared to those from relatively short AQUARIUS records.
Grodsky, S., Reul, N., Chapron, B., Bryan, F., and Carton, J. (24-Feb-16). Aquarius observations indicate that SSS in the shelf water north of the Gulf Stream (between 35N and 45N) experiences interannual variations with more than 1 psu difference between salty and fresh events. Longer JAMSTEC records confirm these SSS variations and show that they are positively correlated with interannual SST.
Cabot, F., Kerr, Y., Lagerloef, G., and Anterrieu, E. (15-Apr-13). SMOS mission has celebrated 3 years in orbit in early November 2012. Throughout these 3 years, it has been made clear that final quality of the geophysical retrieved products, both over land and ocean, highly depends on the brightness temperature map quality.
Bindlish, R., Jackson, T., Zhao, T., Lagerloef, G., Le Vine, D. Yueh, S., and Kerr, Y. (15-Apr-13). A comparison is reported of Aquarius and SMOS brightness temperatures over land and ocean.
Vazquez-Cuervo, J., Fournier, S., Dzwonkowski,B., and Reager, J.T. (27-Aug-18). Four satellite derived sea surface salinity (SSS) datasets are evaluated in the Gulf of Mexico (GoM), three from NASA's Soil Moisture Active Passive (SMAP) mission and one from the European Space Agency's Soil Moisture Ocean Salinity (SMOS) mission. The first two SMAP products are from Remote Sensing Systems (REMSS) with different resolutions of 40 km and 70 km, while the third, a 40 km product, is produced by the Jet Propulsion Laboratory. All products are compared against in situ data from buoys and the World Ocean Database (WOD) in the GoM, a coastal/semi-enclosed basin strongly influence by river discharge.
Fournier, S., Lee, T., and Steele, M. (27-Aug-18). In this work, we present an assessment of the quality of the different satellite SSS products against multiple in situ datasets and we provide an intercomparison of these different satellite SSS products.
Fournier, S., Lee, T., Tang, W., Steele, M., and Yueh, S. (29-Apr-19). Six sea surface salinity products (SMOS, Aquarius, and SMAP) over the Arctic are compared from 2011-2015 and 2015-2017. Overall, they show good agreement with in-situ observations but there are some differences in terms of ice masks and impact of ice concentration.
Grodsky, S.A., Reul, N., Vandermark, D., and Bentamy, A. (30-Apr-19). Shifts in the intertropical convergence zone (ITCZ) in the Atlantic Ocean result in intra-seasonal oscillations in rainfall. Sea surface salinity (SSS) and temperature, precipitation, and wind data are analyzed to understand the ocean's response to rainfall variations. Results indicate that SSS oscillations are detectable by SMAP and distinguishable from signals due to tropical instability waves.
Lee, T., Hasson, A., Bingham, F., Farrar, T., and Boutin, J. (18-Nov-15). NASA field campaign SPURS-2, slated to take place in the Northeastern Tropical Pacific Fresh Pool, aims to improve the understanding of salinity processes in that region associated with high precipitation and active ocean dynamics. Satellite SSS from Aquarius and SMOS provide large-scale context to understand salinity processes in the region, which will complement the in-situ observations to be collected during SPURS-2. As part of the effort in preparation for SPURS-2, we examine the dominant temporal and spatial scales of SSS, using Aquarius and SMOS SSS measurements together with the output from a 18-km resolution ocean circulation model.
Hasson, A.E.A., Lee, T., Bingham, F., Farrar, J.T., and Boutin, J. (24-Feb-16). As part of the effort in preparation for SPURS-2, we examine the dominant temporal and spatial scales of SSS around 10°N and 125°W using Aquarius and SMOS SSS measurements together with a 0.25°x0.25° resolution ECCO (Estimating the Circulation and Climate Experiment of the Ocean) ocean circulation model simulation. This study focuses on sub-seasonal variability.
Presented at the 2016 AGU Fall Meeting
Hasson, A.E.A., Boutin, J., Bingham, F., Lee, T., Farrar, J.T., Supply, A., Puy, M., Morrow, R., and Reverdin, G.P. (16-Dec-16). Sea Surface Salinity (SSS) is one of the key factors influencing the ocean circulation but is also an important indicator of the hydrologic cycle. Understanding processes associated with various SSS regimes is thus crucial to the knowledge of ocean dynamics and of the connection between the ocean and the water cycle. SSS variability is studied between 2010 and mid-2016 in the tropical Pacific Ocean using various datasets such as observations from the satellite missions Soil Moisture Ocean Salinity (SMOS) and Aquarius SAC/D; in situ measurements from Argo, voluntary ships and dedicated campaigns; and a forced simulation of the Nemo ocean model.
Hasson, A., Boutin, J., Puy, M., Reverdin, G., Supply, A., Morrow, R., Lee, T., Bingham, F., and Farrar, T. (25-Apr-17). Sea Surface Salinity (SSS) is one of the key factors influencing the ocean circulation but is also an important indicator of the hydrologic cycle. Understanding processes associated with various SSS regimes is thus crucial to the knowledge of ocean dynamics and of the connection between the ocean and the water cycle. SSS variability is studied between 2010 and mid-2016 in the tropical Pacific Ocean using various datasets such as observations from the satellite missions Soil Moisture Ocean Salinity (SMOS), Aquarius SAC/D and Soil Moisture Active Passive (SMAP); in situ measurements from Argo, voluntary ships and dedicated campaigns; and a forced simulation of the Nemo ocean model. This study focuses mainly on variability north of the Equator, around 10????N. The interannual signal of SSS is particularly intense in this region in 2015, with a very strong and wide freshening and enhanced precipitations.
Perez, R.C., Matano, R.P., Msadek, R., Garzoli, S.L., Meinen, C.S., Chidichimo, M.P., and Palma, E. (19-Nov-15). There are comparatively few studies of Atlantic meridional overturning circulation (AMOC) characterizing the water mass and circulation variability in the South Atlantic subtropical gyre, or how that variability impacts the AMOC in the South Atlantic. Here we use observations and high-resolution models to examine the interannual to decadal variability of sea level anomalies, water mass properties, and wind stress across the South Atlantic subtropical gyre.
Hasson, A., Farrar, T., Boutin, J., Bingham, F., and Lee, T. (07-Nov-18). SMOS, SMAP and Aquarius are useful tools to study large mesoscale features, and results are shown to be coherent with other parameters. Studying the coherence between SMOS, SMAP and Aquarius reduces the effect of noise and non-physical artifacts. Budgets computed using the Zonal-wavenumber-frequency coherence amplitude can reveal processes associated with propagating features.
Boutin, J. and Reversion, G. (06-Nov-18). This presentation provides the context and history of salinity science meetings, as well as major mission milestones in remote sensing of sea surface salinity (SSS). There have been a broad range of approaches to measure salinity, and new techniques and instruments have been developed to further our understanding of SSS and its effect on the ocean. Highlights from previous meetings about salinity science (beginning in 2013) are provided, as well as goals for the current meeting.
Silvy, Y., Guilyardi, E., Durack, P.J., and Sallée, J-B. (08-Nov-18). There have been structures in salinity change in the ocean interior over the last decades. These changes can be attributed, in part, to human activity, and in particular to carbon dioxide emissions. Using models to constrain missing observations was found to be promising for identifying these changes through time. Many regions, however, will need more years or decades of direct observation to detect the impact of human influences.
Grodsky, S., Vandemark, D., Reul, N., Hunter, E., and Carton, J. (19-Sep-17). An investigation into the shelf region of the Northwestern Atlantic, focusing on an anomalous SSS signal impacted by freshwater inputs.
Presented at the 2014 AGU Fall Meeting
Scott, J., Meissner, T., and Wentz, F. (18-Dec-14). Sea-surface temperature (SST) plays an important, and yet to be fully understood, role in sea-surface sailinty (SSS) retrievals. The Version-3 release of Aquarius/SAC-D salinity retrievals applied an empirically derived adjustment to SSS that is a function of SST. This adjustment was derived after noticing regional salinity biases relative to modeled and in situ salinity observations. These SSS biases correlate well with climatological SST maps. While the ΔSSS(SST) adjustment has already been implemented in the ADPS standard processing, there is great value in determining the physical basis of this bias adjustment. Understanding the root causes of this adjustment will enable improved Aquarius's salinity retrievals, as well as ensure that no true SSS-SST correlations or variability are being removed by the adjustment.
Presented at the 2014 AGU Fall Meeting
Kao, H-Y. (18-Dec-14). The Pacific Intertropical Convergence Zone (ITCZ) is a zonal band of atmospheric convective instability, clouds and rainfall near the equator. High-resolution sea surface salinity (SSS) measurements from the Aquarius satellite reveals more detail in the band of lower salinity and a sharp front that aligns with the strong ITCZ atmospheric convection.
Banks, C., Gommenginger, C., Srokosz, M., and Snaith, H. (16-Apr-13). The launch of the SMOS and Aquarius satellites marked a new era in satellite oceanography allowing routine monitoring of the salinity of the world's oceans on synoptic scales. However, there are significant issues affecting the performance of SMOS related to the satellite direction (ascending/descending passes) although the magnitude has decreased with revised versions of the processor.
Yue, X., Zhang, B., He, Y., and Han, Z. (23-July-17). We use multiple satellite observations and numerical simulation to investigate the upper ocean response to Typhoon Kalmaegi in 2014 in the South China Sea (SCS). In this study, significant sea surface temperature (SST) decreasing is observed, which is caused by typhoon-induced vertical mixing and upwelling. The maximum SST cooling is 2°C on the right of the typhoon track since inertial currents rotate in the same direction as the surface wind vectors. We also find an interesting phenomenon that salinity decreases ranging between 0.3 and 0.6 psu on the left side of the typhoon track. We use numerical simulations and in-situ observations to further confirm that salinity reduction is caused by heavy rainfall.
Presented at the 2016 AGU Fall Meeting
Grodsky, S. and Carton, J. (16-Dec-16). The leading mode of the Aquarius monthly anomalous sea surface salinity (SSS) is evaluated within the 50S-50N belt, where SSS retrieval accuracy is higher. This mode accounts for about 18% of the variance and resembles a pattern of the ENSO-induced anomalous rainfall. The leading mode of SSS variability deducted from a longer JAMSTEC analysis also accounts for about 17% of the variance and has very similar spatial pattern and almost a perfect correspondence of its temporal principal component to the SOI index. In that sense, the Aquarius SSS variability at low and middle latitudes is representative of SSS variability that may be obtained from longer records.
Presented at the 2014 AGU Fall Meeting
Drucker, R. and Riser, S. (18-Dec-14). We compare Aquarius 3.0 sea surface salinity with Argo upper mixed layer salinities, using both the standard Aquarius level-2 product and the Combined Active Passive (CAP) algorithm.
Bryan, F. and Bachman, S. (11-Nov-14). The choice of control volume influences the processes that dominate budgets of ocean properties. In this study we analyze the salinity budget of the North Atlantic subtropical salinity maximum region for control volumes bounded by isohaline surfaces. We provide closed budgets based on output from a high-resolution numerical simulation, and partial budgets based on climatological analyses of observations.
Presented at the 2014 AGU Fall Meeting
Bryan, F. (18-Dec-14). In this study we analyze the salinity budget of the North Atlantic subtropical salinity maximum region for control volumes bounded by isohaline surfaces.
Yueh, S., Fore, A., Tang, W., Akiko, H., and Stiles, B. (10-July-16). We investigated the use of L-band active and passive microwave data from the Soil Moisture Active Passive (SMAP) observatory for remote sensing of ocean surface winds during hurricanes. We analyzed the dependence of SMAP data on ocean surface wind speed and direction, and found excellent consistency with the geophysical model functions developed for the Aquarius L-band radar/radiometer although the spatial resolutions of SMAP and Aquarius are distinctly different.
Macelloni, G., Brogioni, M., Pettinato, S., Monti, F., and Casal, T. (15-Apr-13). With the purpose of evaluating the brightness temperature long-time temporal stability of a possible SMOS external calibration reference target an experimental activity, called DOMEX, was carried out in the past years at the Italian-French base of Concordia (Antarctica).
Macelloni, G., Brogioni, M., Pettinato, S., Montomoli, F., Monti, F., and Casal, T. (17-Sep-15). East Antarctic Plateau has been investigated in recent years as a potential candidate for higher reference temperatures. The reason for this interest lies in its geographical location, as well as in the size, structure, spatial homogeneity, and thermal stability of this area.
Tang, W., Yueh, S., Fore, A., and Hayashi, A. (23-July-17). The objective of this study is to investigate the effect of sea surface temperature (SST) on L-band microwave measurements and its implication on sea surface salinity (SSS) retrieval. Of particular interest is in the cold and fresh water where large SSS retrieval errors exist in comparison with Argo data.
Meissner, T. and Wentz, F. (27-Mar-12). Presented at the 2012 Aquarius Calibration/Validation Workshop in Santa Rosa, CA.
Dinnat, E. and Le Vine, D. (10-July-16). Three L-band radiometers have been observing the Earth in order to retrieve soil moisture and ocean salinity. They use different instrument configurations and calibration and retrieval algorithms. In any case, the brightness temperature retrieved at the Earth surface should be consistent between all instruments. One reason for inconsistency would be the use of different approaches for the instrument calibration or the use of different models to retrieve surface brightness temperature. We report on the different approaches used for the SMOS, SMAP and Aquarius instruments and their impact on the observations consistency.
Cabot, F., and Anterrieu, E. (11-Apr-16). Since the launch of the SMOS mission in 2009, two other satellites carrying L-band radiometers joined it on orbit. Aquarius was launched in June 2011 and SMAP in January 2015. Unfortunately, Aquarius ceased operation later that year. All 3 instruments have been operating simultaneously between April and June 2015. Although this golden age of L-band on orbit radiometry was short lived, it allowed for sound comparison of the performances of these 3 radiometers. Moreover, its untimely termination emphasizes the need for reliable inter calibration to build long term consistent archives of brightness temperature and higher level products.
Presented at the 2018 AGU Fall Meeting
Kerr, Y.H., Bindlish, R., Yueh, S.H., Entekhabi, D., Rodriguez Fernandez, N., Lee, T., Wigneron, J-P., Lagerloef, G.S.E., Boutin, J., Escorihuela, M.J., and Anterrieu, E. (13-Dec-18). The Soil Moisture and Ocean Salinity (SMOS) mission was launched in November 2009 and is still fully operational. The Aquarius Radiometer on board SAC-D was launched in June 2011 and operated until July 2015. Finally the Soil Moisture Active and Passive (SMAP) mission was launched in January 2015 and its radiometer has been fully operational. These three missions have a unique feature in common, that is an L band radiometer. For the first time - with SMOS - the globe was operationally covered with such measurement.
Zhou, Y., Lang, R., Dinnat, E., and Le Vine, D. (06-Nov-18). New L-Band measurements of the dielectric constant of seawater at 1.413 GHz have been completed, leading to a small increase in the accuracy of the GW model function at low temperatures. These new measurements (at 34 and 36 PSU) have been incorporated into the model function, which is now more consistent between differing salinities.
Grings, F. (17-Nov-15). The project summary for Project 12 - La Plata Basin Floods and Droughts: Contribution of Microwave Remote Sensing in Monitoring and Prediction. The main achievements of the project focus on soil moisture retrieval using AQ radiometer/scatterometer, monitoring soil moisture conditions in the Pampas Plains, monitoring floods in the Paraná floodplain, multitemporal analysis of forest environments, and MWR radiometer calibration.
Hormann, V., Centurioni, L., Maximenko, N., and Chao, Y. (24-May-17). To improve understanding of the role of near-surface currents in defining the salinity distribution and location of minimum salinity in the northeastern tropical Pacific, a Lagrangian drifter study with about half the drifters fitted with salinity sensors has been designed as part of the SPURS-2 experiment. First results of the ongoing drifter deployments in the eastern Pacific fresh pool under the ITCZ will be presented, highlighting the observed large spatiotemporal variability in near-surface circulation and sea surface salinity.
Presented at the 2014 AGU Fall Meeting
Freilich, M. and Mahadevan, A. (18-Dec-14). Monsoonal freshwater runoff into the Bay of Bengal makes it one of the freshest oceans and results in a large spatial gradient in surface salinity (8-10 psu over 8-10 degrees longitude). Our aim is to understand dispersal and mixing of freshwater in the Bay of Bengal, its underlying mechanisms, and the spatial and temporal patterns of variability using Aquarius salinity data.
Fore, A., Yueh, S., Tang, W., and Hayashi, A. (29-Apr-19). Details on land corrections in JPL processing are presented. Challenges associated with sea ice correction (e.g., variation in position) lead to the conclusion that more work is needed.
Reul, N., Guimbard, S., Chapron, B., and Maes, C. (24-Feb-16). The Eastern Pacific Fresh Pool (EPFP) is a large region of low Sea Surface Salinity (SSS) defined by SSS <34 that develop east of 180°W. Using five years of SMOS SSS and complementary satellite wind, rain, currents, sea surface temperature together with an historical ensemble of in situ products, the present study explores qualitatively the interannual dynamic of the freshpool zonal extent over the period 2010-2014.
Zhou, Y., Lang, R., Dinnat, E., and Le Vine, D.M. (27-Aug-18). A transmission-type TM mode resonant cavity has been employed to determine the seawater dielectric constant at L-band accurately (Lang et al. 2016). Based on the dielectric constant data, a dielectric model function has been generated and applied to retrieve the seawater surface salinity from the Aquarius satellite data (Zhou et al. 2017). The comparison between the retrieved salinity and the in situ data, however, indicated that more accuracy is still needed, especially at low temperature, for the dielectric measurements of seawater.
Freedman, A. (27-Mar-12). Proxy measurement datasets are presented for polar sea ice. Two measurements appear to be best for sensing sea-ice cover: Sigma-0 VV / Sigma-0 HH ratio and Noise-equivalent Sigma-0 (HH or VV). Other measurements are significantly influenced by RFI or other geophysical variables.
Vinogradova, N., Ponte, R., and Buckley, M. (11-Nov-14). Characterizing freshwater fluxes (FWF) over the oceans is a key element in advancing our understanding of climate change. One way to improve knowledge of these fluxes is to use variations in sea surface salinity (SSS). However, the problem is challenging because the relationship between SSS and FWF can depend on complex upper-ocean dynamic processes.
Presented at the 2018 AGU Fall Meeting
Xie, X. and Liu, W.T. (14-Dec-18). The critical dependence of the food production and agrarian economy on rainfall makes the linkage of the oceanic and terrestrial water balances through monsoon of paramount importance to many countries in South Asia. We found that the onset of summer monsoon is always preceded by sea surface temperature (SST) rises above deep convection threshold (approximately 27°C) in both the Bay of Bengal and the Arabian Sea.
Kainulainen, J., Colliander, A., Martin-Neira, M., and Hallikainen, M. (16-Apr-13). The Soil Moisture and Ocean Salinity (SMOS) satellite has measured the L-band brightness temperature of the Earth over three years. The payload instrument MIRAS (Microwave Imaging Radiometer using Aperture Synthesis) measures two-dimensional brightness temperature maps of the L-band radiation by means of interferometry in order to obtain a reasonable angular resolution.
Presented at the 2016 AGU Fall Meeting
Reagan, J.R., Seidov, D., Boyer, T., Zweng, M. (16-Dec-16). Multiple studies have shown that since the mid-20th century near-surface salinity patterns have amplified, with fresh regions becoming fresher and salty regions becoming saltier. This pattern amplification is directly related to an amplification of the global hydrological cycle, with wet regions becoming wetter and dry regions becoming dryer. An amplified hydrological cycle could cause an increase in the number of extreme weather events, with more severe floods and droughts. However, it could also lead to additional freshwater fluxes over the deep water formation regions in the northern North Atlantic which can slow down the Atlantic Meridional Overturning Circulation. With historically unreliable global evaporation and precipitation data, salinity is the main source for tracking changes in the hydrological cycle.
Zhang, L. and Qu, T. (26-Feb-14). Based on the Argo floats data, the low frequency salinity variability of the South Pacific Tropical Water (SPTW) is investigated in this study.
Kolodziejczyk, N., Reverdin, G., Gaillard, F., and Lazar, A. (19-Nov-15). Low-frequency variability of salinity is observed in the Subtropical South Atlantic over the period 2002-2013 with the Argo gridded product ISAS.
Skou, N. Kristensen, S.S., Sobjarg, S.S., and Balling, J.E. (09-Sep-15). An area in Antartica has been mapped by an airborne L-band. The area is well suited for calibration checks for the spaceborne instruments like SMOS, Aquarius, and SMAP.
Tony, L., Fournier, S., Gordon, A., and Sprintall, J. (08-Nov-18). The Maritime Continent is a "chokepoint" of global ocean circulations, with the Indonesian throughflow affecting the ocean and climate. The sea surface salinity in the Maritime Continent affects the vertical structure in the Indonesian through flow, which influences the Indo-Pacific exchanges. Understanding this region is important for climate, but it has been poorly sampled by ARGO and other in situ instrumentation. Recent advances in salinity remote sensing since have provided a new ability to fill the knowledge gaps in this important area. SMAP was able to provide an unprecedented capability to monitor the sea surface salinity in the Maritime Continent region. A seasonal freshwater "plug" was observed that exists in both the boreal winter and boreal spring. Overall, the observations point to the Maritime Continent water cycle as being an important regulator and low-latitude checkpoint of global ocean circulation.
Presented at the 2018 AGU Fall Meeting
Lee, T., Fournier, S., Gordon, A.L., and Sprintall, J. (14-Dec-18). The Maritime Continent (MC) offers the only low-latitude connection of the world oceans. The oceanography within the MC regulate the characteristics of the Indonesian throughflow (ITF), linking the tropical Pacific and Indian Oceans, with strong implications to climate variability and biogeochemistry. Previous studies suggested that the relatively fresh South China Sea (SCS) waters advected by the monsoonal wind-driven ocean currents create an upper-layer "freshwater plug" in the Java Sea and Makassar Strait during boreal winter, which modulates the vertical structure and variability of the ITF. Using a suite of satellite observations to characterize the freshwater plug and examine its sources, we find that the main source of the freshwater is derived directly from the Java Sea precipitation and the Kalimantan(Borneo) rivers.
Le Vine, D.M., and Dinnat, E. (30-Apr-19). Issues associated with matching up satellite data with in-situ data are examined including differences in spatial resolution, accuracy, and frequency. Three options are considered: closest point of approach sampling (CPA), CPA with averaging, and "All-in-Box" (i.e., all samples in a time-space box). Aquarius sea surface salinity (SSS) data are used to evaluate the three options using various time and space scenarios. A draft proposal for Pi-MEP is also included.
Schmitt, R.W., Blair, A., St Laurent, L., and Schanze, J. (27-Feb-14). The North Atlantic Salinity Maximum is the world's saltiest open ocean S-max and was the focus of the recent SPURS process study. It is formed by an excess of evaporation over precipitation and the wind-driven convergence of the subtropical gyre. Such salty areas are getting saltier with global warming (a record high SSS was observed in SPURS) and it is imperative to determine the relative roles of surface fluxes and oceanic processes in such trends.
Presented at the 2014 AGU Fall Meeting
Qu, T. and Zhang, L. (18-Dec-14). This study investigates the mean property distribution and large scale variability of the high salinity subtropical underwater (STUW) in the North Atlantic, using recently available Argo profiles at observed levels. Our analysis indicates that, once subducted, the STUW spreads in the subtropical North Atlantic as a vertical salinity maximum near 25.5 kg m-3.
Asher, W., Drushka, K., Jessup, A., Thompson, E., and Clark, D. (24-May-17). During the 2016 SPURS-2 field experiment in the eastern equatorial Pacific Ocean, the controlled flux technique (CFT) was used to infer surface turbulence before, during, and after rainstorms. In this paper, preliminary results from the SPURS-2 CFT measurements will be presented to show the effect of rain on turbulence dissipation at the ocean surface. This data will be used along with concurrent measurements of salinity and temperature profiles in the upper meter of the ocean to better understand the generation and evolution of fresh lenses generated by rain.
Nystuen, J.A., Yang, J., and Asher, W.E. (26-Feb-14). In this study, the authors present a sampling strategy and an objective acoustic classification of the underwater sound generated by wind and rain that can be used to retrieve wind speed and rain rate.
Boutin, J.J., Reul, N., D'Amico, F., Marchand, S., Tenerelli, J., Vergely, J.L., Hasson, A., Kolodziejczyk, N., Reverdin, G., Supply, A.,Tarot, S., and Vialard, J. (25-May-17). The Soil Moisture and Ocean Salinity (SMOS) mission monitors Sea Surface Salinity (SSS) from space since January 2010. This European Space Agency (ESA) Earth Explorer mission provided the first L-band radiometric observations of the Earth using interferometry. SMOS has demonstrated the feasibility of monitoring SSS and its variability from space with a precision of 0.15-0.3 (in regions free from radio frequency interferences and more than 1000km away from coasts).
Köhler, J., Serra, N., Bryan, F., Johnson, B.K., and Stammer, D. (12-Feb-18). The physical processes that control the seasonal mixed layer salinity (MLS) budget are examined through a combined analysis of an ensemble-mean sea surface salinity (SSS) product based on SMOS and Aquarius data and a high-resolution ocean model simulation using the National Center for Atmospheric Research Community Earth System Model driven by COREv2 forcing. The analyses reveal that SSS variations can be used as a proxy for MLS variations, taking therefore advantage of the high spatial and temporal resolution of the satellite SSS data.
Presented at the 2016 AGU Fall Meeting
Köhler, J., Stammer, D., Serra, N., and Bryan, F. (16-Dec-16). "Space-borne salinity data in the Indian Ocean are analyzed over the period 2000-2015 based on data from the European Space Agency’s (ESA) ""Soil Moisture and Ocean Salinity"" (SMOS) and the National Aeronautical Space Agency’s (NASA) ""Aquarius/SAC-D"" missions. The seasonal variability is the dominant mode of sea surface salinity (SSS) variability in the Indian Ocean, accounting for more than 50% of salinity variance. Through a combined analysis of the satellite and ARGO data, dominant forcing terms for seasonal salinity changes are identified. It is found, that E-P controls seasonal salinity tendency in the western Indian Ocean, where the ITCZ has a strong seasonal cycle.
Lagerloef, G. (11-Nov-14). Opening remarks from Gary Lagerloef, Aquarius Principal Investigator, for the 2014 Aquarius/SAC-D Science Team Meeting in Seattle, WA.
Ballabrea, J., Hoareau, N., Garcia, E., Turiel, A., and Portabella, M. (26-Nov-14). Satellite imagery has revealed a series of ocean structures as meandering fronts, eddies and filaments. A high percentage of ocean energy has been found to accumulate at a range of scales (ranging from tens to a few hundred kilometers) known as the ocean mesoscale. Thanks to the SMOS and Aquarius missions, more than four years of satellite-derived sea surface salinity (SSS) data are available. For the first time, satellite data have been providing quasi global, synoptic information of the spatial variability of the ocean surface salinity.
Kolodziejczyk, N. and Maes, C. (24-Feb-16). The horizontal thermohaline structure at the sea surface is investigated in the Indian Ocean at length scales from five to hundreds of kilometers, i.e. at submeso- to meso-scales.
Edson, J., Graham, R., Paget, A., Clayson, C.A., and Farrar, T. (24-May-17). A comprehensive set of meteorological instrumentation was deployed on the R/V Revelle and 3-m discus buoy during the SPURS-2 experiment in the tropical Eastern Pacific Ocean. These measurements are being used to quantify the amount of precipitation versus evaporation (P–E) that drives a freshwater flux into or out of the upper ocean, respectively.
Soldo, Y., Dinnat, E., and Le Vine, D.M. (29-Apr-19). Idea to use actual SMAP measurements over land to compute land correction; however, brightness temperature needs to be estimated for angles other than 40 degrees.
Karszenbaum, H., Grings, F., Carballo, F., Barraza, V., Bruscantini, C., Salvia, M., and Perna, P. (11-Apr-12). Comparison of data from various Argentine soil moisture projects using three satellite instruments: AMSR-E, SMOS and Aquarius. Conclusion regarding retrieval algorithm performance is that, although promising, it is not satisfactory at this time in this region. In terms of the SMOS/Aquarius: different sensor configuration, engineering, and acquisition strategies and temporal characteristics make comparison difficult; too few simultaneous data; and nevertheless, sensitivity to rain events in Chaco forests is observed.
Clymer, B., May, C., Schneidar, L., Madero, F., Labanda, M., Jacob, M., and Jones, L. (11-Nov-14). This poster concerns the on-orbit validation of the antenna beam pointing and corresponding instantaneous field of view earth location for the CONAE Microwave Radiometer (MWR). The MWR is a three-channel radiometer operating at 23.8 GHz (H-Pol) and 36.5 GHz (V- and H-Pol), which has two multi-beam parabolic reflector antennas in a pushbroom configuration, with eight beams per frequency (36.5 GHz looking forward and 23.8 GHz looking aft producing 24 simultaneous beams).
Clymer, B., May, C., Schneider, L., Madero, F., Labanda, M., Jacob, M.M., and Linwood Jones, W. (10-Sep-15). The purpose of the Aquarius/SAC-D mission is to provide measurements of global sea surface salinity (SSS), which will be used to understand climatic changes of the global water cycle and how these changes influence the general ocean circulation.
Gallo, J., Jones, L., Rocca, D., and Biswas, S. (20-July-10). Overview of: pre-launch calibration, which will be checked in the laboratory using hot/cold loads and in the themo-vacuum chamber using absorbers; and post-launch calibration, which will be done using monthly cold sky maneuvers, along with "vicarious" and inter-satellite calibrations.
Madero, F. (11-Apr-12). Presentation includes some known issues with the Microwave Radiometer (MWR) such as: invalid geolocation at high latitudes; geolocation errors due to star tracker error from moon interference; and need to update the version of antenna patterns used by the processor.
Ramiondo, H. and Madero, F. (20-July-10). Presentation includes: Microwave Radiometer (MWR) overview and characteristics; definition of products and processing levels; information about the data processor; simulation data; science and supplementary data; radiometric and geometric corrections; and cross calibration using Windsat.
Jones, L., Gallo, J-C., Rocca, D., Biswas, S., and Hejazin, Y. (11-Apr-12). Presentation give status of preliminary Microwave Radiometer (MWR) L1B Brightness Temperatures algorithm, including: release of Version 4.0 (V4.0) to the Aquarius Cal/Val team; reasonable results have been produced using the V4.0 geophysical algorithm; MWR "smear-effect" discovered and empirical correction algorithm developed; and Version 5.0 algorithm has been tuned to WindSat using "smear-corrected" antenna temperature.
Freedman, A. (26-Mar-12). A variety of remaining observations and issues are presented, including a look at inclination angles, monitoring loopback power, and drift in echo.
Torrusio, S. (17-Nov-15). An overview of the SAC-D Mission, including an overview of the instruments, applications, data, products, projects and the mission's legacy.
Meissner, T., Wentz, F., and Scott, J. (13-Nov-14). The Aquarius Version 3.0 salinity retrievals have salty biases at mid-high latitudes and fresh biases in the tropics and subtropics when compared to ARGO or HYCOM. In addition we observe biases between the three Aquarius beams.
Presented at the 2012 AGU Fall Meeting
Carton, J., Grodsky, S.A., Nicolas, R., Lagerloef, G.S.E., Reverdin, G.P., Chapron, B., Yves, Q., Kudryavtsev, V.N., and Kao, H-Y. (03-Dec-12). Hurricane strength increases dramatically with increasing sea surface temperature (SST) and decreases in response to entrainment of cooler sub-mixed layer water into the ocean mixed layer. At its seasonal peak the Amazon/Orinoco plume covers a region of one million square kilometers in the western tropical Atlantic with more than 1m of extra freshwater, creating a near-surface barrier layer that inhibits this mixing and warms to temperatures >29C.
Carton, J., Grodsky, S., Johnson, B., and Bryan, F. (12-Nov-14). Here we examine the detailed salt balance of the mixed layer in a 0.1 degree resolution multi-decadal simulation of the global ocean/ice system forced by observed historical surface fluxes (1979-2010), with the flux calculations carried out on the original grid every time step. Initial conditions were provided by a simulation forced by Normal Year forcing. The simulation is generally realistic with a slight negative bias in salinity. Here we focus on a comparison of the salt balance as it varies with latitude from the rainy tropics through the dry subtropics and into the humid midlatitudes.
Presented at the 2014 AGU Fall Meeting
Anderson, J. and Riser, S. (18-Dec-14). During the Salinity Processes in the Upper Ocean Regional Study (SPURS) I field campaign a high-density grid of Argo-type profiling floats were deployed surrounding the central mooring. The sixteen (16) floats were deployed in a 4 x 4 array with approximate 0.5 degree spacing and were programed to profile from 2000 meters to the surface every 5 days.
Anderson, J. and Stephen, R. (11-Nov-14). The first Salinity Processes in the Upper Ocean Regional Study (SPURS) I field campaign took place in the approximate center of the north Atlantic surface salinity maximum (~25°N, 38°W). During SPURS I 16 Argo-type profiling floats were deployed in a high-density, 4 by 4 grid surrounding the central mooring with approximate 0.5 degree spacing.
D'Addezio, J.M. and Bingham, F.M. (28-Aug-18). Submesoscale resolving simulations of the North Arabian Sea and western Pacific using the Navy Coastal Ocean Model (NCOM) for 2016 were examined to estimate sea surface salinity (SSS) subfootprint variability (SFV). Footprint sizes of 10 km, 20 km, 40 km, and 100 km were tested. The high-resolution model grids were partitioned into regularly spaced, larger subdomains to simulate each footprint size. SFV was quantified by the annual median SSS standard deviation within each of the respective subdomains.
Tang, W., Yueh, S., and Hayashi, A. (27-Mar-12). The ascending and descending passes of Aquarius have had an observed difference. The question posed here is whether ocean surface rain could explain some of the ascending/descending asymmetry that has been observed.
Li, Z., Gordon, A.L., Busecke, J., and Bingham, F.M. (26-Feb-14). The SPURS-I field campaigns reveal that the subtropical North Atlantic region is a far more complex environment than the previously envisioned. A data assimilative high-resolution model has been set up to support the SPURS field campaigns by providing real-time predictions and conducting reanalyses and simulations post the campaigns.
Lee, W., Kaihatu, J.M., Anis, A., and Li, D. (25-Feb-16). Hypersaline discharges from desalination plants in the Persian Gulf can potentially affect the environment of the Gulf, and the influence of the shamal winds from the north of the Gulf is not clear. In this study, the distribution of seasonal salinity and its variations due to the effect of the shamal, is investigated using the Delft3D-FLOW hydrodynamic model.
Song, Y., Lee, T., Moon, J., Qu, T., and Yueh, S. (12-Nov-14). Here, we propose an extended surface-salinity layer (ESSL) within a global ocean circulation model to diagnose skin sea surface salinity without increasing the computational cost, while allowing comparable solutions with both satellite and Argo salinity at the respective depths. Cross-comparisons with Aquarius and Argo data show that the gridded Aquarius surface salinity has a much stronger seasonal variability than the gridded Argo top-level salinity at 5 m or 10 m, particularly in regions of high precipitation variability, suggesting the exist of strong near-surface vertical salinity stratification.
Presented at the 2014 AGU Fall Meeting
Song, Y.T., Lee, T., Moon, J-H., Qu, T, and Yueh, S.H. (18-Dec-14). Here, we propose an extended surface salinity layer within a global ocean circulation model to diagnose skin SSS without increasing the computational cost, while allowing comparable solutions with both satellite and Argo salinity at the respective depths within the corresponding uncertainty limits.
Wentz, F.J. and Meissner, T. (30-Mar-16). The Aquarius galaxy model is fairly complex. It integrates the antenna over a rough ocean surface based on an existing astronomy map. SMAP (Soil Moisture Active Passive), which looks fore and aft (i.e., "dual looks"), provides the means to directly determine the galaxy map for SMAP. About one year of data from SMAP were investigated in two cases: (1) averaged over all winds, and (2) using only winds below five meters per second. Next step is to assess whether the differences observed are due to antenna patterns or scattering models. This will be done by fine tuning the modification, implementing in the Aquarius test bed, symmetrizing the galaxy correction, and assessing the improvement.
Fournier, S., Vialard, J., Lengaigne, M., Lee, T., Gierach, M.M., and Chaitanya, A.V.S. (12-Feb-18). The Bay of Bengal receives large amounts of freshwater from the Ganga-Brahmaputra river during the summer monsoon. The resulting upper-ocean freshening influences seasonal rainfall, cyclones, and biological productivity. Sparse in situ observations suggest that the East India Coastal Current (EICC) transports these freshwaters southward after the monsoon as an approximately 200-km wide, 2000-km long 'river in the sea' along the East Indian coast. Sea surface salinity (SSS) from the Soil Moisture Active Passive (SMAP) satellite provides unprecedented views of this peculiar feature from intraseasonal to interannual timescales
Fournier, S., Tong, L., and Gierach, M. (18-Nov-15). The Mississippi River, the largest river in North America, provides a major contribution of freshwater into the Gulf of Mexico and has implications to ocean circulation in the subtropical North Atlantic. In this study, we use data from the NASA Aquarius/SAC-D and ESA SMOS satellites to study the seasonal and interannual variations of sea surface salinity (SSS) in the Gulf of Mexico near the outflow of the Mississippi River.
Reul, N. and Lee, T. (26-Nov-14). An invited talk by Nicholas Reul and Tony Lee, providing an overall context for ocean salinity, from the satellite perspective. The talk reviews the importance of studying ocean salinity and the benefits of looking at data from the unique vantage point of space. The basics of the SMOS and Aquarius SAC-D missions are provided, as well as a high-level review of some of the research outcomes thus far.
Fournier, S., Gaultier, L., Vandemark, D.C., Salisbury, J., Lee, T. and Gierach, M. (25-Feb-16). Large rivers are important to marine biogeochemistry and air-sea interactions. The freshwater inputs associated with major river plumes modify the local and regional sea surface salinity (SSS) and in the mean time carry a large amount of organic and inorganic particulates into the ocean. With the launches of the NASA Aquarius/SAC-D missions and the ESA Soil Moisture and Ocean Salinity (SMOS), we are now able to use the low-resolution SSS observations in combination with altimetry and high-resolution ocean color observations to monitor the physical and biogeochemical properties of river plumes, such as the Amazon River, the focus of this study.
Liu, W.T. and Xie, X. (24-Feb-16). Using satellite data, we have characterized the influence of monsoon on the variation of surface salinity in the Bay of Bengal.
Riser, S.C. and Anderson, J. (26-Feb-14). In this study, the authors present observations from a suite of profiling floats in the Bay of Bengal equipped with enhanced temperature and salinity sensors capable of measuring water properties very near the sea surface.
Nardelli, B.B., Droghei, R., and Santoleri, R. (17-Apr-15). Availability of accurate remotely-sensed sea surface salinity (SSS) measurements is crucial to investigating fundamental aspects of the global hydrological cycle, ocean dynamics and marine biogeochemistry. The European Space Agency (ESA) Soil Moisture Ocean Salinity (SMOS) mission has been specifically designed for this aim. However, SMOS data display a high level of noise with respect to the signal they have to detect.
Shcherbina, A., Certunioni, L., D'Asaro, E., Hodges, B., Rainville, L., Riser, S., and Volkov, D. (24-May-17). During the first part of SPURS-2 experiment, a cluster of autonomous instruments was deployed for a 100-day 1,800-km coordinated quasi-Lagrangian drift through the North Pacific intertropical convergence zone (ITCZ). The cluster conducted multi-platform observations of the ocean surface boundary layer structure and dynamics in a quasi-Lagrangian frame of reference minimizing the effects of horizontal advection. We will present preliminary results of this coordinated study, focusing on the evolution of upper-ocean stratification and shear in response to storm-induced rainfall and wind bursts.
Roy, A., Royer, A., Derksen, C., Toose, P., Brucker, L., Mialon, A., Lanlois, A., and Kerr, Y.H. (11-Apr-16). Snow and frozen ground play a crucial role in climatological and hydrological processes, and are key factors in modulating energy, water, and carbon budgets. L-band space-borne missions such as Soil Moisture Active Passive (SMAP), Soil Moisture and Ocean Salinity (SMOS), and Aquarius have the potential to provide enhanced information on the surface freeze/thaw (F/T) state over northern regions. It is a key parameter for studies of terrestrial hydroclimatology and ecosystem processes. In this presentation, we first present an analysis over Canadian sites of the L-band brightness temperature (TB) variations from SMOS, Aquarius and first SMAP data in order to characterize the freeze/thaw (FT) soil state, including in winter when a dry snow cover exists.
Raed, M.A., Gari, J.M., Lorenzo, B., Sedeño, A., Antes, M., Cuello, A., and Sánchez, Y. (12-Nov-13). Satellite data has proven to be very important for monitoring and evaluating natural resources. The objective of using the SAC-D satellite system in this study is to compare previous work with optical Landsat, SPOT digital data, and polarimetric RADARSAT 2 with the global study given by SAC-D optical, thermical and microwave digital data.
Jones, L., Hejazin, Y. and Aslebagh, S. (17-Nov-11). An overview of the retrieval algorithms for columnar water vapor, oceanic wind speed, and rain rate. Preliminary radiometer geophysical retrievals are compared with collocated WindSat environmental records.
Scott, J., Hilburn, K., Meissner, T., and Wentz, F. (13-Nov-13). Summary: (1) MWR provided instantaneous measurement of rain rate (rain flagging, surface splashing, freshening); (2) for cloud water and liquid absorption there is marginal improvement over using NCEP cloud water fields; L-band liquid cloud water absorption is very small; and (3) wind speeds are not useful for Aquarius roughness corrections.
Masuelli, S., Tauro, C., and Jones, L. (19-July-10). Presentation included information on the Microwave Radiometer (MWR), including: introduction to the MWR instrument; project plan (e.g., simulators, prototypes, schedule); surface retrievals; atmospheric retrievals; sea ice concentration and Level 2 algorithms.
Tauro, C.B., Hejazin, Y., Jacob, M.M., and Jones, L. (12-Nov-13). In this work we present the wind speed retrieval obtained using MWR instrument data. The retrieval model was developed jointly between CONAE and CFRSL, and is actually used to generate Wind Speed L2 product distributed by CONAE and PODAAC.
Presented at the 2012 AGU Fall Meeting
Labanda, M.F., Jacob, M.M., Farrar, S., Raimondo, H.A., and Jones, W.L. (04-Dec-12). We present in this paper a comparison between the results obtained before and after the correction with noticeable improvement in MWR products, i. e., more realistic geophysical retrieval products. The improvement is demonstrated by both global and regional studies over land and ocean.
Jones, L., Hejazin, Y., Al-Nimri, S. (13-Nov-14). The AQ baseline approach to provide roughness correction uses the AQ scatterometer ocean radar backscatter to infer excess ocean emissivity. In this poster an alternative MWR derived sea surface roughness correction algorithm is presented that uses a new semi-empirical microwave Radiative Transfer Model (RTM) to estimate the excess ocean emissivity using ancillary data such as sea surface temperature and ocean surface wind vector.
Rabolli, R. (12-Nov-13). SAC-D Deputy PI Monica Robolli summarizes MWR Science including: Level-2 products (columnar water vapor, sea ice concentration, total atmospheric transmisivity, wind speed); inter-agency collaborations; calibration efforts; applying MWR data to Aquarius; and applications.
Masuelli, S. and Salgado, H. (17-Nov-15). The prototype L2 algorithm for MWR Sea Ice Concentration was first developed in 2010, with the first version being released in 2012 and a second version released in 2014. The first version experienced artifacts due to the Smear Effect, and resulted in the overestimate over the open sea. The second version included a correction for the Smear Effect, better land mask, an atmospheric filter, and was calibrated using six months of data.
Jones, L. and Farrar, S. (17-Nov-11). MWR has a parabolic torus reflector antenna design with 8 component beams. In this talk, examples of the smearing effect of the radiometer offset, as well as worst-case examples for land and ocean crossings.
Lindstrom, E. (15-Apr-13). Powerpoint presentation on the Ocean Salinity Program at NASA.
Lindstrom, E. (18-Sep-17). A report from the NASA Physical Oceanography Program, providing an overview of the Salinity Continuity Program, presented by Dr. Eric Lindstrom.
Lindstrom, E. and Vinogradova, N. (29-Apr-19). Overview of NASA Physical Oceanography and Salinity Continuity Programs are discussed along with upcoming activities and opportunities.
Lindstrom, E. (14-Nov-14). In this presentation, the author provides an overview of the NASA Earth Science and Physical Oceanography program.
Lindstrom, E. (12-Nov-13). The author presents an overview of ESD operating missions, planned missions (2014-2023), and the Physical Oceanography Program (funding, outlook, upcoming meetings).
deCharon, A., Lauter, C., and Taylor, L. (23-May-17). As a NASA pathfinder mission dedicated to public engagement, Aquarius made significant strides in broadening interest in salinity beyond the scientific community. Leveraging the infrastructure and thematic approach developed for Aquarius, new communication and public engagement endeavors are being conducted to align with scientific objectives. Through close coordination and interaction with the science community, these collective efforts will demonstrate how a better understanding of salinity science and its ties to ocean circulation, climate, and the water cycle can benefit society.
deCharon, A. and Vazquez, J. (29-Aug-18). As a NASA pathfinder mission dedicated to public engagement, Aquarius made significant strides in broadening interest in salinity beyond the scientific community. Using lessons learned from this experience, we will help the Ocean Salinity Science Team (OSST) contribute to NASA's strategic communications goals in specific and measurable ways. By doing so, the OSST will collectively contribute to broader ocean and climate literacy efforts.
Yueh, S., Entekhabi, D., O'Neill, P., and Entin, J. (23-July-17). The Soil Moisture Active Passive (SMAP) observatory was launched January 31, 2015, and its L-band radiometer and radar instruments became operational during April 2015. This paper provides a summary of the quality assessment of its baseline soil moisture and freeze/thaw products as well as an overview of new products.
Matheos, S. (11-Apr-12). Overview of the National Sea Data System and its mission to ensure accessibility to data and marine information of the Southwestern Atlantic Ocean and Antarctica. Objectives include: continuous updating of shared marine data and information; consolidating registration and capturing of marine information and for maintaining the databases; and providing access to basic information on the marine environment under defined rules and procedures.
Song, Y.T and Moon, J-H. (17-Apr-15). By comparing a newly available Aquarius-derived sea surface salinity (SSS) with the Argo in-situ measurements and an ocean circulation model, we have examined the near surface salinity stratifications in the tropical Atlantic and Indian Oceans.
Riser, S. and Anderson, J. (14-Nov-13). In this study, the authors used data from profiling floats enhanced with an auxilliary Surface Temperature and Salinity (STS) CTD to observe the upper ocean response to rainfall.
Presented at the 2012 AGU Fall Meeting
Anderson, J.E. and Riser, S. (03-Dec-12). Observations of near-surface temperature and salinity obtained from Argo-type profiling floats enhanced with an auxiliary Surface Temperature and Salinity (STS) CTD are presented. Using the STS unit, high vertical resolution (<10 cm) data in the near-surface layer were acquired nearly all the way to the sea surface.
Song, Y.T., Lee, T., Moon, J., Qu, T., and Yueh, S.H. (25-Feb-16). Using a recently developed ESSL (extended surface-salinity layer) model [Song et al., JGR, 2013], we have examined the near-surface salinity stratifications with emphasis on understanding of the dynamical processes that differ from one region to another.
Santos-Garcia, A., Jones, L., and Jacob, M.M. (31-Mar-15). This talk highlights near-surface salinity stratification observed by SMOS and Aquarius under rainy conditions. Outputs from the Rain Impact Model (RIM) are compared to observations from both satellites.
Santos-Garcia, A., Jacob, M.M, and Jones, W.L. (31-July-15). ESA's Soil Moisture Ocean Salinity (SMOS) Earth Explorer mission globally measures ocean salinity every three days with a Microwave Imaging Radiometer using the Aperture Synthesis (MIRAS) radiometer. Also 7-day global ocean salinity measurements are available from NASA's Aquarius (AQ) L-band push-broom radiometer on-board of Aquarius/SAC-D satellite. The Central Florida Remote Sensing Laboratory has analyzed AQ sea surface salinity (SSS) retrievals in the presence of rain and has developed a Rain Impact Model (RIM) that predicts transient near-surface salinity stratification based upon the corresponding rain accumulation over the previous 24 hours.
Clayson, C.A., Bogandoff, A., Farrar, T., Edson, J., St. Laurent, L., and Schmitt, R. (24-May-17). This presentation discusses observations and modeling of the upper ocean stratification during the SPURS-1 and SPURS-2 field campaigns, including the variation in stratification seen as a result of diurnal warming, freshwater inputs, or both. The resulting mixing and temporal evolution of the stably stratified upper layers will also be discussed.
Volkov, D., Dong, S., Goni, G., Lumpkin, R., and Foltz, G. (25-Apr-17). Despite the importance of sea surface salinity (SSS) as an indicator of the hydrological cycle, many details of air-sea interaction responsible for freshwater fluxes and processes determining the near-surface salinity stratification and its variability are still poorly understood. This is primarily due to the lack of dedicated observations. The advent of satellites capable of monitoring SSS, such as the Soil Moisture and Ocean Salinity (SMOS), Aquarius, and Soil Moisture Active-Passive (SMAP) missions, has greatly advanced our knowledge of SSS distribution and variability. However, the spatial resolution of satellite retrievals is too coarse to study the upper-ocean salinity changes due to patchy and transient rain events. Furthermore, the satellites measure salinity within the upper 1 cm skin layer, which can significantly differ from in situ SSS measured at 5 m depth by most Argo floats.
Hodges, B.A. and Fratantoni, D.M. (27-Feb-14). In this study, vertical variability in temperature and salinity in the upper few meters of the ocean is examined using year-long datasets from three Wave Glider autonomous surface vehicles and short missions under low-wind conditions by Iver 2 EcoMapper autonomous underwater vehicles.
Subrahmanyam, B. and Grunseich, G. (26-Feb-14). In this study we show that data from the newly launched NASA Aquarius/SAC-D salinity mission can accurately detect the Madden-Julian Oscillation propagation.
Presented at the 2018 AGU Fall Meeting
Shoup, C.G. and Bulusu, S. (13-Dec-18). The Madden-Julian Oscillation (MJO) is a mode of intraseasonal variability that affects the tropics through air-sea interaction. Anomalous convective and clear-sky conditions associated with the MJO propagate eastward at 3-5 m s-1over the tropical Indian and Pacific Oceans repetitively with a typical period of 40-50 days. Although the MJO was first detected in the zonal wind over the tropical Pacific, its association with many other atmospheric and oceanic properties has been documented. Using salinity to study the MJO is important because it allows for atmospheric conditions to be inferred from the freshwater flux (precipitation minus evaporation) on which SSS is highly dependent.
deCharon, A., Taylor, L., Companion, C., Cope, R., and Kuring, N. (12-Nov-13). The Aquarius website has been revamped to include: new interactive features; information retrieval from or about multimedia galleries, news, mission status, events, faqs, science meetings, and people; and a new design to meet scientists' needs (e.g. science maps, educational resources for public engagement efforts, archived webinars).
Dinnat, E., Soldo, Y., and Le Vine, D. (18-Jan-17). Presentation outlines approaches for land correction in Aquarius data, including using improved land emissivity model in simulator and empirical brightness temperature model-derived L-band measurements. New land corrections have been evaluated using co-located Aquarius and Argo buoy sea surface salinity (SSS). Results are presented for the Mediterranean Sea, including data from the Aquarius/SMAP overlap period. Mapped along-track SSS in the Mediterranean and statistical analyses show improvement with the new land correction, including fewer anomalously low SSS values near coasts and better correlation with Argo data.
Madero, F. (11-Apr-12). Presentation includes some known issues with the New Infrared Sensor Technology (NIRST) such as: geolocation errors due to star tracker error from moon interference; and issues with generation of sun and moon position in Earth-Centered, Earth-Fixed (ECEF) reference frame.
Marraco, H. (20-July-10). Presentation includes general information about New Infrared Sensor Technology (NIRST), including: calibration setup; what is measured; system transfer function; active and reference pixels; integration with SAC-D; and geographic targets.
Marraco, H. (11-Apr-12). Early results from New Infrared Sensor Technology (NIRST), including qualitative results, are presented. Issues include striping in data; non uniformity in data; lack of complete barrel temperature distribution; variable gain from pixel to pixel, etc.
Madero, F. and Ramiondo, H. (20-July-10). Presentation includes: new Infrared Sensor Technology (NIRST) overview and characteristics; definition of products and processing levels; information about the data processor; science and supplementary data; radiometric and geometric corrections; and product formats.
Kalemkarian, M. (20-July-10). Presentation includes description of derived products and documentation for fire mapping/fire radiative power, sea surface temperature, land surface temperature, and volcanic activity monitoring data. In addition, the validation and quality control of these products is described.
Turiel, A. and Gonzalez, V. (16-Apr-13). Due to its interferometric design, the direct measurements by SMOS payload, MIRAS, are the visibilities of the signal defined on an hexagonal grid. The visibility field can be expressed as the Fourier transform of brightness temperature in real space modulated by the antenna gain pattern. Retrieving brightness temperatures (the actual physical variable of interest) from visibilities requires to implement an appropriate reconstruction algorithm.
Parambil, A.V., Vialard, J., Lengaigne, M., Keerthi, M.G., Boutin, J., Vergely, J-L., and Marchand, S. (12-Feb-18). The Bay of Bengal (BoB) exhibits a contrasted sea surface salinity (SSS), with very fresh water induced by heavy monsoonal precipitation and river discharge to the north, and saltier water to the south. The strong northern BoB haline stratification is believed to limit vertical mixing of heat and nutrients, with strong impacts on tropical cyclones intensity and primary production. While in situ data is denser since the advent of the Argo program, it is still far from sufficient to provide complete maps of seasonal SSS. The advent of satellite salinity remote sensing (SMOS, AQUARIUS, SMAP) offers a unique opportunity to provide synoptic maps of the BoB SSS every ~8 days. While recent studies have shown a good performance of the so far ~2 years SMAP record in the BoB, the Aquarius mission is now over, and previous retrievals from the longer (2010 to now) SMOS mission did not perform well in this region. In this work, we provide an in-depth assessment of the new CATDS level-3 2010-2017 SSS from the SMOS instrument
Dinnat, E.P., Le Vine, D.M., De Amici, G., and Piepmeier, J. (29-Aug-18). We report on the science requirements and technical definition of a next-generation spaceborne instrument for ocean salinity remote sensing. The new sensor will be designed to improve retrievals in cold water and enhance applications closer to the shores where there are important interactions between land, ocean and ice. With the advent of the SMOS and Aquarius instruments in 2010, it has become possible to monitor global sea surface salinity (SSS) on a weekly to monthly basis. These sensors have also shown the increased complexity of retrieving SSS in the cold water of the high latitudes and close to land and ice boundaries. These limitations have hindered the application of space-borne SSS observations to the study of important processes such as ocean freshening due to ice melt and river outflow, especially in the high latitude and in narrow costal currents.
Cotlier, C., Vicioso, B., Pacino, C., Balparda, L., Lãpez, D., and Cotlier, G. (17-Nov-15). This presentation outlines the use of the DMSP-OLS sensor to examine urban activity and marine light pollution by measuring night-time light.
Marraco, H. and Colazo, M. (17-Nov-15). The process and results of the calibration of NIRST (New Infrared Sensor Technology) and algorithms for sea surface temperature.
Kalemkarian, M.M., Colazo, M.E., and Marraco, H.G. (12-Nov-13). This poster summarizes a methodology to perform absolute calibration for NIRST on board the SAC-D/Aquarius satellite.
Kalemkarian, M.M., Colazo, M.E., and Marraco, H.G. (14-Nov-13). This presentation summarizes a methodology to perform absolute calibration for NIRST on board the SAC-D/Aquarius satellite.
Marraco, H., Labanda, M., Raymondo, H., Colazo, M., and Kalemkarian, M. (13-Nov-14). After considerable work sorting several unforeseen obstacles NIRST is now ready for science. Several examples of the camera's capabilities for revealing land and sea surfaces temperatures distributions with a whole calibrated range are shown. A brief description of the steps leading to this successful goal is also given. This description includes the pitfalls incurred during the camera design, their causes and cures.
Marraco, H. (14-Nov-13). The author shares results from cold sky and radiometric calibrations of the New InfraRed Sensor Technology (NIRST) thermal cameras onboard SAC-D and provides a brief example that compares brightness temperatures with color temperatures.
Xie, P., Boyer, T., Bayler, E., Xue, Y., Byrne, D., Reagan, J., Locarnini, R., Sun, F., Joyce, R., and Arun, K. (17-Apr-13). A technique has been developed to produce analyses of sea surface salinity over the global ocean through blending information from in situ measurements and satellite retrievals.
Presented at the 2012 AGU Fall Meeting
Xie, P., Boyer, T., Bayler, E. J., Xue, Y., Byrne, D.A., Reagan, J.R., Locarnini, R.A., and Kumar, A. (03-Dec-12). A prototype analysis of monthly sea surface salinity (SSS) has been constructed on a 1olat/lon grid over the global ocean by blending information from in situ measurements and satellite retrievals. Three data sets are included as inputs to the blended analysis, i.e., in situ SSS measurements aggregated and quality controlled by NOAA/NODC, and the passive microwave retrievals from the Aquarius/SAC-D and SMOS satellites, received and post-processed at NOAA/STAR.
Bayler, E. (28-Aug-18). NOAA/NCEP has been running real-time operational ocean data assimilation systems since 2004. NOAA continues to pursue satellite sea-surface salinity (SSS) data for its operational models, specifically the National Weather Service's (NWS) real-time Real-Time Ocean Forecast System (RTOFS) and the real-time seasonal-interannual Global Ocean Data Assimilation System (GODAS), the ocean component of NOAA's coupled Climate Forecast System (CFS). NOAA's ocean data assimilation systems and core ocean models are both in transition.
Hodges, B., Schmitt, R.W., and Fratantoni, D.M. (12-Feb-18). At night, the ocean surface cools, forming a superadiabtic temperature gradient that drives convection. The subsurface structure of these convective motions is investigated with measurements of temperature and salinity from autonomous surface vehicles (Wave Gliders). The observations were made as part of NASA's Salinity Processes in the Upper Ocean Regional Study (SPURS) and include measurements with high vertical and horizontal resolution in the upper meter made by a novel 'Salinity Rake' fitted to a Wave Glider. The vertical gradients, the horizontal convective scales, and the diel cycle of convection are characterized.
Li, L., Schmitt, R.W., Ummenhofer, C., and Karnauskas, K.B. (24-Feb-16). Water evaporating from the subtropical oceans sustains precipitation on land. Moisture exiting the ocean surface leaves an imprint on sea surface salinity (SSS). Thus, the question arises of whether variations in subtropical SSS can provide mechanistic insight into, and predictability of, terrestrial precipitation. Using a series of observational and reanalysis products, we provide evidence that springtime SSS in the subtropical North Atlantic is a robust, physically meaningful predictor of terrestrial precipitation during the subsequent monsoon season.
Khvorostyanov, D., Boutin, J., Vergely, J.L., and Thouvenin-Masson, C. (06-Nov-18). The CATDS Salinity Expertise Center focuses on the remote sensing of sea surface salinity, and particularly, the scientific algorithm development and data exploitation of ESA's Soil Moisture and Ocean Salinity (SMOS) satellite mission. In this presentation, the authors compare SMOS CATDS salinities with in situ (ARGO OI, TARA) and SMAP products.
Asher, W., Jessup, A., and Drushka, K. (13-Nov-14). Precipitation on the ocean forms salinity and temperature gradients in the top few meters of the ocean surface. If present, these gradients will complicate comparing salinity measured by ARGO drifters at typical depths of five meters to salinities retrieved using L-band microwave radiometers such as Aquarius and SMOS at depths on the order of 0.01 m.
Asher, W. (28-Nov-14). Vertical salinity gradients in the top few meters of the ocean surface can exist due to the freshwater input from rain. If present, they will complicate comparing salinity measured by ARGO drifters at typical depths of a few meters to salinities retrieved using L-band microwave radiometers such as SMOS and Aquarius, whose measurement depths are on order of 0.01 m. Therefore, understanding the spatial scales and the frequency of occurrence of these vertical gradients and the conditions under which they form will be important in understanding sea surface salinity maps provided by SMOS and Aquarius.
Walesby, K.T., Vialard, J., and Ward, B. (26-Feb-14). The Air-Sea Interaction Profiler (ASIP) is a novel, upwardly-rising instrument which has previously been used to measure microstructure within the upper ocean. Here the authors present results acquired using ASIP from a research cruise in the tropical Indian Ocean.
Presented at the 2018 AGU Fall Meeting
Iler, S. and Drushka, K. (14-Dec-18). Freshwater transport, surface fluxes, and turbulent mixing in the upper ocean are components of the global hydrologic cycle, which is critically important to study in the context of Earth's warming. Rainfall can form lenses of relatively fresh water at the ocean surface which persist until they are mixed away by turbulent processes or advection. Previous studies have suggested that stratification suppresses turbulence below and enhances turbulence within fresh lenses until lenses are mixed away by wind or nighttime convection. However, the specific relationships between wind, rain, and dissipation rates at the sea surface, and the turbulent conditions necessary to mix away fresh lenses, have not been widely studied. The objective of this work is to analyze these relationships and determine the effects of turbulence on the evolution of fresh lenses.
Oglietti, F. (11-Apr-12). Presentation includes assessment of the Aquarius/SAC-D observatory and orbit dynamics. Conclusions include: orbit acquistion sequence was successfully performed (e.g., correction of launch injection errors, achievement of nominal ground track on 07-Aug-11, etc.); orbit maintenance operations successful (e.g., ground track longitude, descending node height, "frozen orbit" within margins, etc.); and CONAE Orbit Dynamics Services are operational.
Banks, C., Srokosz, M.A., Cipollini, P., Snaith, H.M., Blundell, J., Gommenginger, C., and Tzortzi, E. (25-Feb-16). The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite has provided sea surface salinity (SSS) data for over six years. It has been shown that the operational ESA Level 2 SSS data have significant spatially and temporally varying biases between measurements from ascending passes (SSSA; SMOS moving south to north) and descending passes (SSSD; SMOS moving southwards). The data used for this study were from two SMOS SSS climatologies one based on SSSA and the other from SSSD. These climatologies have been used to calculate salinity anomalies, which are shown to have significantly reduced the spatio-temporal biases.
Kao, H. and Lagerloef, G. (26-Feb-14). The detailed salinity fronts (SFs) in the tropical Pacific are first revealed by Aquarius observations. The strongest SFs are found at the edges of freshpools on both sides of the Pacific and the south boundary of the intertropical convergence zone.
Gordon, A.L. and Giulivi, C.F. (17-Apr-13). Improved in situ and remote sensing observational tools, along with high resolution models, allow us to ask the question (which we have a chance to answer): What role does the ocean mesoscale play in compensating the air-sea flux of heat and freshwater?
Rainville, L., Lee, C.M., Eriksen, C.C., Farrar, J.T., and Plueddemann, A.J. (26-Feb-14). Observations collected during the Salinity Processes Upper-ocean Regional Study (SPURS) field campaign in the subtropical North Atlantic are used to identify and quantify the processes responsible for the formation of a 100-m thick surface mixed layer in winter, and its restratification in spring and summer.
Colliander, A., Dinnat, E., Le Vine, D., Chae, C-S., and Kainulainen, J. (16-Apr-13). SMOS and Aquarius are ESA and NASA missions, respectively, to make L-band measurements from the Low Earth Orbit.
Li, L., Schmitt, R., Ummenhofer, C., and Karnauskas, K. (23-May-17). In this presentation, we provide observation-based evidence that springtime salinity in the subtropical North Atlantic can be a very useful predictor of terrestrial precipitation with a one season lead. Specifically, high springtime SSS in the northeastern portion of the subtropical North Atlantic is followed by excessive monsoon precipitation in the African Sahel, whereas high SSS in the western North Atlantic is indicative of extreme summer precipitation in the US Midwest.
Maes, C., Kolodziejczyk, N., Prigent, A., and Gaillard, F. (23-May-17). Among the different physical processes contributing to the present climate changes and their impact on the ocean productivity and marine ecosystems, little attention has been paid to the large-scale contributions of stratification changes within the water column. Stratification, which is associated with the density difference between the surface and the deeper layers, characterizes the stability of the water column, and therefore influences the potential for vertical exchange of properties such as nutrients or dissolved oxygen.
Presented at the 2018 AGU Fall Meeting
Fournier, S. (14-Dec-18). Salinity is a key parameter reflecting the global water cycle changes, including impacts of precipitation, evaporation, and runoff. The water cycle is dominated by ocean-atmosphere exchanges, with 86% (76%) of the evaporation (precipitation) occurring over the ocean. The net evaporation-precipitation ends up on land, and returns to the ocean via runoff. Although runoff only accounts for about 10% of the total oceanic freshwater input, it is critical to the coastal oceans through its effects on marine biogeochemistry and physical processes. Terrigenous matters carried by rivers can have a profound impact on marine ecology, and river discharge affects the surface layer buoyancy, ocean currents, and air-sea interactions.
Presented at the 95th AMS Meeting
Liu, W.T. and Xie, X. (05-Jan-15). The ocean as the source and sink of carbon dioxide is important to global warming, ocean biogeochemistry, and ecology, but its quantitative variation is insufficiently known. The exchange depends on the difference in fugacity (partial pressure) of carbon dioxide between sea and air, and a transfer velocity.
Liu, W.T. and Xie, X. (17-Apr-13). One year of coincident observations of ocean surface salinity by Argo, SMOS, and Aquarius are compared in their identifications of the temporal and spatial characteristics of major ocean features. In the Circumpolar Current, neither SMOS nor Argo shows any seasonal variation of surface salinity, but Aquarius shows a summer peak and a winter low.
Meissner, T., Wentz, F., Lagerloef, G., and Le Vine, D. (18-Nov-15). With the demise of Aquarius the ability of SMAP to measure ocean salinity has gained importance. We discuss the adaption of the Aquarius salinity retrieval algorithm to SMAP and address important differences between the Aquarius and SMAP.
Meissner, T., Wentz, F.J., and Scott, J.P. (25-Feb-16). This presentation discusses the adaption of the Aquarius salinity retrieval algorithm to SMAP. It includes corrections for signals from the rough ocean surface, the atmosphere and ionosphere, cold space, galaxy, sun, moon as well as sidelobe and cross polarization effects from the SMAP antenna.
Liu, W.T. and Xie, X. (13-Nov-13). This presentation addresses the ocean-atmosphere hydrologic balance, with a focus on time-series studies from regions in the Pacific Ocean based on data from Argo/OSCAR, Aquarius, SMOS, and TRMM. Studies of time-series data in the Pacific Intertropical Convergence Zone (ITCZ) indicate that advection and freshwater storage changes were out of phase. In the tropical Pacific "warm pool", evaporation minus precipitation (E-P) lagged the ocean hydrological balance. In the Kuroshio Extension, evaporation dominated the phase of water flux and advection was small. In the Pacific subtropical gyre, freshwater flux and ocean change did not balance.
Xie, X. and Liu, W.T. (26-Feb-14). We have derived ocean surface water exchanges from satellite data, both as a divergence of integrated water transport in the atmosphere and as the difference between evaporation and precipitation.
Schmitt, R.W., Schanze, J.J., Li, L., and Ummenhofer, C. (25-Feb-16). The ocean has a much larger water cycle than the land, with global ocean evaporation of 13 Sverdrups being 10 times larger than the sum of all river flows. This disparity and the different dynamics of dry surfaces, have led to an unfortunate disconnect between terrestrial hydrologists and oceanographers. Here we show that there is in fact a close coupling between the water cycles of ocean and land.
Yueh, S. (28-Mar-12). Aquarius data collected near the galactic plane allows for the recovery of ocean wave slope. The retrieved wave slope improves sea surface salinity retrieval by about 1 psu near the galactic plane, under light wind conditions.
Presented at the 2014 AGU Fall Meeting
Gordon, A. (18-Dec-14). Each ocean basin displays its own 'personality', reflecting its degree of isolation or connectivity to the global ocean, its place in the interocean exchange network and associated ocean overturning circulation systems, as well as regional circulation and air-sea exchange patterns.
Williams, G., Svendsen, G., Visinitini, N., González, R., Esteves, J.L., Gagliardini, A., and Narvarte, M. (12-Nov-13). Two oceanographic cruises were carried out in San Matías Gulf, in the north of the Argentine Patagonian Continental Shelf in the context of the first surveys in the study zone under the SAC-D/Aquarius mission. In this poster, we present and compare in-situ data with temperature estimates by the NLSST-MODIS algorithm.
Matano, R.P., Combes, V., and Palma, E.D. (19-Nov-15). We investigate the pathways of the meridional overturning circulation in the South Atlantic Ocean using the results of an eddy-resolving, nested model.
Clarke, A.J. and Zhang, X. (28-Aug-18). If intense rain falls uniformly at a rate of 50mm/hour over a circular lake of radius a, and there is no evaporation, then after 1 hour the sea level would rise by 5cm. But how is the sea level rise distributed over a similar circular region if the rain falls over the open ocean? Analytical results for this idealized rainfall with rate R provide physical insight about how the size of the ocean response depends on the rainfall rate, its duration, and its horizontal scale.
Vazquez, J., Tang, W., Hayashi, A., and Tsontos, V. (12-Nov-14). Three different sea surface salinity (SSS) data sets were used for comparing the annual signal of salinity in the Gulf Stream. These were both the Project version 3.0 SST-adjusted and non-adjusted data sets as well as SSS based on the v3.0 Combined Active-Passive algorithm.
Camara, I., Kolodziejczyk, N., Mignot, J., Lazar, A., and Gaye, T.A. (19-Nov-15). The physical processes controlling the mixed layer salinity (MLS) seasonal budget in the tropical Atlantic ocean are investigated using a regional configuration of a ocean general circulation model.
Dinnat, E. and Brucker, L. (14-Nov-14). The objective of this talk is to present the high-latitude products and to summarize their recent applications over the cryosphere. The effect of the 2012 summer melt event at Summit, Greenland created sudden brightness temperature (TB) drops, larger than 15 and 20 K at vertical and horizontal polarization, respectively. We will also emphasize the impact of snow surface changes on the Aquarius L-band TB observations at Dome C (75S, 123E). Finally, we will show that the scatterometer observations are sensitive to the anisotropy of the Antarctic ice sheet.
Bruscantini, C.A., Grings, F., Maas, M., and Karszenbaum, H. (12-Nov-13). The Microwave Radiometer on board the SAC-D/Aquarius mission, launched in June 2011, is a Dicke radiometer operating at 23.8 GHz (H-Pol) and 36.5 GHz (H/V-Pol). MWR channels are useful to provide ancillary data for the various retrievals to be performed with Aquarius regarding ocean and land applications. In this study we report some of the calibration results obtained with two different techniques: a land cross-calibration with Windsat and the Vicarious Cold calibration.
Bruscantini, C.A., Grings, F., Maas, M., and Karszenbaum, H. (13-Nov-13). The Microwave Radiometer on board the SAC-D/Aquarius mission, launched in June 2011, is a Dicke radiometer operating at 23.8 GHz (H-Pol) and 36.5 GHz (H/V-Pol). MWR channels are useful to provide ancillary data for the various retrievals to be performed with Aquarius regarding ocean and land applications. In this study we report some of the calibration results obtained with two different techniques: a land cross-calibration with Windsat and the Vicarious Cold calibration.
Vandermark, D., Feng, H., Grodsky, S., Reul, N., Wilkin, J., Hunter, E., and Levin, J. (29-Apr-19). The Northwest Atlantic shelf (i.e., off the New England coast) has salinity assets such as long-term moorings, gliders, thermosalinographs (TSG), gliders, and data-assimilating models. These can be used to understand and complement satellite-derived salinity retrievals in terms of ocean processes and calibration/validation.
Lindstrom, E. (19-July-10). Aquarius NASA Program Scientist provided an overview of: ocean salinity science team; salinity field program; NASA solicitations; and establishment of the Sea Surface Temperature Science Team.
Suarez, M. (19-July-10). Detailed information on the Aquarius/SAC-D science and orbit design requirements. In addition, information about post-launch activities (e.g., timeline of fairing separation, S- and X-band contacts, orbit maneuvers) was shared.
Tsontos, V. Feldman, G. (18-Jan-17). Close-out action items for archiving Aquarius mission documents is based on NASA/Earth Observing System Data and Information System (EOSDIS) mission preservation guidelines and the recent mission decommission approach used for TRMM. Based on these, a checklist spreadsheet has been developed for mission artifacts to be preserved at the Physical Oceanography Distributed Active Archive Center (PO.DAAC). PO.DAAC and Goddard Space Flight Center teams have developed a joint inventory of artifact holdings, along with the planned disposition of these these items. The artifacts from Aquarius science activities and will be closed out by December 2017.
Vazquez, J. and Tsontos, V. (11-Apr-12). Overview of the Aquarius data archival system, Physical Oceanography Distributed Active Archive Center (PO.DAAC), located at the NASA Jet Propulsion Laboratory. Conclusions: PO.DAAC is hosting and providing timely access to the full range of Aquarius data sets and a variety of data monitoring and user support services and tools; and plans to continue working closely with the Goddard Space Flight Center to ensure the timeliness and integrity of data transfers for distribution, in addition to providing quality documentation and user support services.
Kao, H-Y., Carey, D., Schanze, J., and Lagerloef, G.S.E. (30-Apr-19). Update on SVDS includes details on flexible match-up tools for the OSST Cal/Val team and the best match-up for the general public and Pi-MEP. Global validation statistics for each version of SMAP data is presented (i.e., Version 2 @ 70 km, Version 3.3 @ 40 km and @ 70 km). The approach criteria for – and examples of – Aquarius and SMAP match-ups are presented including search radius, time window, and smoothing method. Next steps include regional validation case studies (SPURS-1, SPURS-2) and "Salinity Snake" validation.
Presented at the 2014 AGU Fall Meeting
Nicolas, R. (18-Dec-14). In this talk, we will present examples demonstrating how SMOS-derived SSS data are being used to better characterize key land-ocean and atmosphere-ocean interaction processes that occur within the marine hydrological cycle. In particular, we shall illustrate how SMOS and its ocean mapping capability provides observations across the world's largest tropical ocean fresh pool regions and we will discuss intra-seasonal to interannual precipitation impacts as well as large-scale river runoff from the Amazon-Orinoco and Congo rivers and its offshore advection.
Presented at the 2016 AGU Fall Meeting
Martins, M.S. and Stammer, D. (16-Dec-16). The salinity budget of the upper tropical Pacific Ocean underneath the double Intertropical Convergence Zone (ITCZ) is studied using the Soil Moisture and Ocean Salinity (SMOS) and Aquarius surface salinity observations as well as in situ salinity measurements.
Salvia, M., Grings, F., Bruscantini, C., Barraza, V., Perna, P., Karszenbaum, H., and Ferrazzoli, P. (10-Sep-15). This paper compares the performance of Aquarius, SMOS and AMSR2 data to estimate the fraction of flooded area and mean water level inside a wetland, in the framework of an active/passive flood monitoring algorithm.
Boutin, J., Reverdin, G., and Martin, N. (17-Apr-15). The Soil Moisture and Ocean Salinity (SMOS) satellite mission monitors sea surface salinity (SSS) over the global ocean for more than 5 years. In previous studies, Boutin et al. (2014) have shown a clear freshening of SMOS SSS under rain cells of about -0.14pss/mm/hr at moderate wind speed (3-12m/s). This order of magnitude is compatible with in situ drifters observations taken at 45cm depth while SMOS SSS are at about 1cm depth and at a mean spatial resolution of 43km.
Lee, T. (25-May-17). This presentation describes the perspectives for future SSS missions based on community inputs during 2015-2016 to the “2017-2027 Decadal Survey for Earth Science and Applications from Space” organized by the U.S. National Academies. The community inputs recognized three major areas for strengthening spaceborne salinity observing capabilities: (1) improvement of high-latitude SSS accuracy, (2) enhancement of spatial resolution (thereby getting closer to the coasts), and (3) mission continuity. In particular, the need to improve high-latitude satellite SSS stems from the fact that L-band radiometers have poor sensitivity to SSS in cold waters (<5C), and from the importance of high-latitude SSS to deep-water formation, heat and carbon sequestration, and global ocean circulation as well as the related property transports.
Tsontos, V., Vazquez, J., and Jiang, Y. (29-Apr-19). Release of in-situ datasets (Saildrone, SPURS2), new web-based tools for field campaign support, and other announcements are shared. Summary of the status of salinity archival/distribution support under NASA's Salinity Continuity Program, including both satellite sea surface salinity and field campaign datasets.
Cotlier, C.G., Pacino, C., Cornero, C., Balparda, L., Cotlier, G., and López, A.G. (14-Nov-13). Esta presentación aborda una metodología para identificar y caracterizar la noche marina contaminación lumínica a través de imágenes satelitales nocturnas en las siguientes ciudades: Buenos Aires, Atenas, Barcelona, Nápoles, Nueva York y Estambul. Estas áreas costeras han experimentado un rápido demográfico, urbano y el crecimiento del turismo. Esto provocó un aumento considerable de la luz artificial en términos de alcance e intensidad. Un resultado ha sido la alteración nociva del estado natural, causando inestabilidad, desorden, daño o molestias a los ecosistemas.
Asher, W.E., Jessup, A.T., and Clark, D. (27-Feb-14). A towed, surface-following profiler was deployed from the N/O Thalassa during the 2012 Subtropical Atlantic Surface Salinity Experiment (STRASSE). measurements show that positive salinity gradients are commonly present at the ocean surface for wind speeds less than 4 m s-1 under conditions when the average daily insolation exceeds 300 W m-2.
Asher, W., Jessup, A., and Clark, D. (14-Nov-13). Conclusions from this study include: (1) evaporation in the presence of a diurnal warm layer can produce positive near-surface salinity gradients at low wind speed; (2) vertical gradients in T and S are spatially correlated; and (3) unless relative humidity is unrealistically low, positive salinity gradients probably do not represent a significant issue for Aquarius.
Lee, M., Vayghan, A.H., Liu, D-C., and Yang, W-C. (23-July-17). Albacore tuna (Thunnus alalunga) is one of the important commercial species of the longline fishery in the southern Indian Ocean (SIO). The satellite-based oceanographic data of net primary production (NPP), sea-surface temperature (SST), sea surface salinity (SSS), mixed layer depth (MLD), sea-surface height (SSH) and eddy kinetic energy (EKE), were used to evaluate the effects of oceanographic conditions on the hotspot habitat for Albacore tuna and to explore the spatial variability of these features in the SIO using the generalized additive model (GAM) and maximum entropy models (MaxEnt). The results from the Maxent and GAM revealed its potential for predicting the spatial distribution of Albacore tuna and highlight the use of multispectral satellite images for describing habitats. In these two models, the spatial habitat patterns were explained predominantly by SST (17-21°C) and indicated that SST is the most influential factor in the geographic distribution of Albacore tuna. Hoptspot habitat formation were also possibly related to the MLD (60-120 m), NPP (250-450 mg C/m2d1) and SSH (0.4-0.6 m).
Ho, D.T. (12-Mar-18). Background, data, and observations of the effect of rain on air-sea CO2 flux.
Thompson, E., Drushka, K., Asher, W., Schanze, J., Jessup, A., and Clark, D. (24-May-17). This study seeks to understand the impact of convective and stratiform rainfall on salinity stratification observed during the 2016 SPURS-2 experiment. Previous observational studies have demonstrated a wind-speed-dependent correlation between in-situ salinity stratification and maximum rain rate. However, questions remain about the temporal lag between the maximum rain rate and evolution of the freshwater lens, and how rain intensity impacts the lifetime of a freshwater lens.
Lagerloef, G. (31-Oct-12). Presented at the 2012 Aquarius Calibration/Validation Workshop at Goddard Space Flight Center.
Tang, W., Yueh, S., Fore, A., and Hayashi, A. (29-Apr-19). The lack of in-situ data in the Arctic Ocean motivates development of a sea ice correction algorithm using SMAP and Aquarius data. Three regions are highlighted to distinguish signatures of multi-year and first-year sea ice.
Lagerloef, G. (24-Feb-16). An important scientific goal for satellite salinity observations is to document oceanic climate trends and their link to changes in the water cycle. This study is a preliminary examination of multi-year sea surface salinity (SSS) trends from analyses of SMOS and Aquarius data, years 2010-2015 to assess the feasibility of monitoring such trends from satellite.
Parard, G., Alvera-Azcarate, A., Barth, A., and Beckers, J. (24-Feb-16). Sea Surface Salinity (SSS) data from the Soil Moisture and Ocean Salinity (SMOS) mission is analysed over the North Atlantic ocean using DINEOF (Data Interpolating Empirical Orthogonal Functions). DINEOF is a technique that reconstructs missing data and removes noise by retaining only an optimal set of EOFs.
Meissner, T., Wentz, F., and Hilburn, K. (12-Nov-13). This presentation discusses the three major steps in the Aquarius Level 2 salinity retrievals to get from the current V2 to the proposed V3 release, and their impact on instrument performance: (1) improved surface roughness correction; (2) empirical adjustment of correction for reflected galactic radiation; and (3) Q/C flagging. One major remaining problem is undetected RFI.
Mercado, G. (14-Nov-13). The author presents an overview of the SAC-D/Aquarius Data Collection System, identifying office/group, program/project, type of measurement, datalogger class, and DCP site locations.
Piepmeier, J. (16-Nov-11). Freely forcing radiometer calibration bias to <dTA>=0 could potentially mask geophysical modeling errors. The objective of this proposal is to constrain bias correction to instrument behavior. This talk outlines the approach, algorithm, and the convergence of model parameters.
Soldo, Y., Le Vine, D., Dinnat, E., de Matthaeis, P., Hong, L., Gales, J., and El-Nimri, S. (30-Mar-16). This presentation addressed proposed changes and issues for V5 Aquarius data processing. There was a focus on three items: (1) additional radio frequency interference (RFI) flagging, (2) emissivity model, and (3) beam 2. Existing flagging misses some "noise-like" RFI thus it is recommended to add a flag based on fixed thresholds. This would be applied to retrievals over land (not the ocean) and not remove any data. The proposed change to the Aquarius V5 land emissivity model would make it more consistent with the model used by SMAP (Soil Moisture Active Passive). Inter-beam differences for the three Aquarius beams have been examined with respect to sea surface salinity and Faraday rotation angle, showing possible issues with Beam 2.
Edson, J., Clayson, C.A., Farrar, T., Graham, R., and Paget, A. (12-Mar-18). The status of research into the fate of fresh water (precipitation) in the Intertropical Convergence Zone (ITCZ) is summarized in this presentation, including meteorological and near-surface data collection on board the R/V Revelle in 2016/2017; deployment and recovery of the WHOI buoy with a DCFS and LI-7500 systems capable of measuring momentum, heat and mass fluxes; and future work.
Edson, J.B., Clayson, C.A., Farrar, J.T., Paget, A., and Graham, R. (12-Feb-18). A comprehensive set of atmospheric and oceanic data was collected on the R/V Revelle and 3-m discus buoy during the SPURS-2 experiment in the tropical Eastern Pacific Ocean. These measurements are being used to quantify the amount of precipitation versus evaporation (P-E) that drives a freshwater flux into or out of the upper ocean, respectively.
Presented at the 2016 AGU Fall Meeting
Delcroix, T.C., Soviadan, D., Chaigneau, A., and Boutn, J. (16-Dec-16). High-resolution ocean model results as well as few sporadic observations collected in different regions indicate that mesoscale eddies imprint distinguishable changes on collocated Sea Surface Salinity (SSS) and/or precipitation (P) distribution. This presentation shows this is indeed the case for the tropical Pacific, by collocating 6 years (2010–2016) of SMOS-derived SSS, TRMM-derived P and AVISO-derived sea level anomalies. The main characteristics of mesoscale eddies are first analyzed in sea-level altimetry maps, and their signature is then determined using concomitant satellite-derived SSS and P data.
Delcroix T., D. Soviadan, A. Chaigneau, and J. Boutin (25-Apr-17). High-resolution ocean model results as well as sporadic observations collected in different regions indicate that mesoscale eddies imprint distinguishable changes in collocated Sea Surface Salinity (SSS) and/or precipitation (P) distribution. This presentation shows this is indeed the case for the tropical Pacific, by collocating 6 years (2010-2016) of SMOS-derived SSS, TRMM-derived P and AVISO-derived sea level anomalies. The main characteristics of mesoscale eddies are first identified in sea-level altimetry maps, and their signature is then determined using concomitant satellite-derived SSS and P data.
Dasso, S. and Lanabere, V. (17-Nov-15). The van Allen radiation belts contain energetic particles, trapped by the geomagnetic field. Short term variability of these particles are determined by the geomagnetic activity, which is mainly determined by the conditions of the solar wind near Earth and are strongly affected by geomagnetic storms. These storms are associated with changes in both the composition and energy of the population of particles in the van Allen radiation belts. The main aim of the present work is to characterize several aspects of the proton populations using observations from the detector ICARE-NG/CARMEN-1, aboard SAC-D.
Ruf, C. and Chen, D. (27-Mar-12). An assessment of the state of radio frequency interference (RFI) and its affect on the Aquarius signal.
Skou, N., Balling, J., and Kristensen, S. (20-July-10). Conclusions include: RFI is generally present in areas investigated; RFI is very variable in time, and space; polarimetric signatures from SMOS satellite instrument looks like those from airborne campaign thus methods investigated using airborne data can be applied; and polarimetric "glitch detector" looks very promising.
Dinnat, E. (15-Nov-11). In the assessment of the radiometer pointing accuracy, it was found that there is good agreement of model to observation at full land and full ocean locations. There should be small impact of model uncertainty on relative levels during transitions.
de Matthaeis, P. (31-Mar-15). The detection algorithm for RFI is presented, as well as a proposed approach for parameter tuning.
Santos-Garcia, A., Jacob, M., and Jones, L. (11-Nov-14). The purpose of this poster is to describe the rain accumulation product and to present validation results using independent environmental data records (EDR) WindSat rain retrievals. The WindSat EDR's have a large number of rain event collocations (<30 min) with the AQ observation.
Jacob, M., Santos-Garcia, A., and Jones, L. (30-Mar-16). This presentation began by addressing sea surface salinity (SSS) differences between Aquarius data and the HYCOM, which have been observed during simultaneous rain events. A majority of these events have shown significant reductions in satellite-derived SSS. Instantaneous rainfall causes strong SSS reduction and salinity stratification at the surface. Following the rain event, wave mixing and diffusion reduce the salinity over a time period of several hours. Aquarius SSS measurements in the presence of rain can be significantly fresher than the bulk salinity at greater than one meter of depth. For this work, the Aquarius salinity model has been applied to SMAP (Soil Moisture Active Passive). The weighting function for Aquarius footprint has been modified to better match SMAP's instantaneous field of view (IFOV). RIM's performance with SMAP data was very good at predicting SSS, compared to AQ and SMOS (Soil Moisture Ocean Salinity) retrievals, providing a robust quality flag for identification of salinity stratification.
Jacob, M., Santos-Garcia, A., Jacob, M., Jones, L., and Asher, W. (13-Nov-14). This paper presents results of a recent empirical investigation into the impact of rain on the Aquarius (AQ) sea surface salinity (SSS) measurements. Results demonstrate that AQ SSS measurements are realistic characterizations of a transient dilution of the surface salinity, but they are NOT representative of the bulk salinity at 5 m depth given by HYCOM.
Jacob, M., Santos-Garcia, A., and Jones, L. (18-Jan-17). Presentation provides an outline of the RIM variables that will be produced for Version 5 of Aquarius data processing, including rain impact variables, other rain parameters (i.e., instantaneous rain rate, rain accumulation over previous 24 hours, and beam fill fraction), and flagging. Data analysis shows that RIM correlates well with Aquarius; however, data were presented to help evaluate whether the current 24-hour time duration window should be reduced (e.g., to 3, 6, 12, or 18 hours). Preliminary results suggest that the difference between RIM 24-hour data and 12- or 18-hour data is less than 0.01 psu. Future analysis will focus on wind speed impacts.
Presented at the 2016 AGU Fall Meeting
Jones, L., Jacob, M.M., Asher, W., Drushka, K., and Santos-Garcia, A. (16-Dec-16). Rainfall over oceans produces a layer of fresher surface water, which can have a significant effect on the exchanges between the surface and the bulk mixed layer and also on satellite/in-situ comparisons. For satellite sea surface salinity (SSS) measurements, the standard is the Hybrid Coordinate Ocean Model (HYCOM), but there is a significant difference between the remote sensing sampling depth of ~ 0.01 m and the typical range of 5-10 m of in-situ instruments. Under normal conditions the upper layer of the ocean is well mixed and there is uniform salinity; however, under rainy conditions, there is a dilution of the near-surface salinity that mixes downward by diffusion and by mechanical mixing (gravity waves/wind speed). This significantly modifies the salinity gradient in the upper 1-2 m of the ocean, but these transient salinity stratifications dissipate in a few hours, and the upper layer becomes well mixed at a slightly fresher salinity.
Santos-Garcia, A., Jacob, M.M., Jones, L., and Asher, W. (25-Feb-16). This research addresses the effects of rainfall on Aquarius (AQ) and Soil Moisture Ocean Salinity (SMOS) satellite sea surface salinity (SSS) retrievals using a macro-scale Rain Impact Model (RIM) that predicts transient SSS stratification based upon the rain accumulation and ocean surface wind speed over the previous 24 hours.
Anderson, J.E. and Riser, S.C. (26-Feb-14). Using data from profiling floats enhanced with an auxiliary Surface Temperature and Salinity (STS) CTD, the upper ocean response to rainfall is observed.
Presented at the 2016 AGU Fall Meeting
Thompson, E.J., Asher, W., Drushka, K., Schanze, J., Jessup, A.T., and Clark, D. (16-Dec-16). Although in situ observations have shown that fresh lenses are common in the presence of rain, attempts to correlate the magnitude and lifetime of the surface freshening with rain rate using field data have not produced a definitive relationship. The reasons for this are most likely that in situ rain rate measurements represent the freshwater flux to the ocean surface at a single point in space and time, whereas the fresh lens is the result of the integrated rainfall over time and space, convoluted with the evolution of the fresh lens. Therefore, it is possible that integrated, upstream rainfall estimates might provide a better correlate for the presence of fresh lenses than in situ measurements at a point. This hindcast study seeks to determine the utility of NASA GPM IMERG satellite measurements of rain relative to in situ collocated rain measurements in predicting the occurrence and duration of 0-1 m freshwater stabilization of the ocean.
Yang, J., Nystuen, J.A., Asher, W.E., and Jessup, A.T. (14-Nov-13). Five STS profiling drifters equipped with PAL passive acoustic rain gauges were deployed in the Equatorial Pacific Ocean in 2011. The 2-year long set acoustic spectra data from these floats now provide time series from which rainfall statistics in this region can be estimated. Here, initial results from the application of an improved data classification scheme to the STS/PAL data are presented.
Yang, J., Nystuen, J.A., Asher, W.E., Jessup, A.T., and Riser, S.C. (26-Feb-14). Knowledge of rainfall frequency, intensity, and duration over the ocean is critical in boh understanding the global hydrological cycle and calibrating and validating ocean surface salinity measured by instruments such as Aquarius and SMOS. Five STS profiling drifters equipped with PAL passive acoustic rain gauges were deployed in the Equatorial Pacific Ocean in 2011. The 2-year long time series of acoustic spectra from these floats now provide enough data from which rainfall statistics in this region can be estimated.
Drushka, K., Clark, D., Asher, W., Chickadel, C., Jessup, A., Thomson, J., and Thompson, E. (22-May-17). Rain falling on the ocean produces buoyant surface layers of relatively fresh, cool water that are subsequently mixed laterally and vertically into the water column. Because it is difficult to make measurements near the sea surface, relatively little is known about the dynamics of this mixing — and as a result, our understanding of how rainfall affects upper ocean salinity is limited. Here, we consider the response of the upper meter of the ocean using three months of measurements collected during the Friday Harbor Rain Experiment.
Asher, W., Drushka, K., Thompson, E.J., Jessup, A.T., Clark, D. (12-Feb-18). Rain on the sea surface can produce a stable near-surface layer of fresher water with a lifetime of O(1-10) hours and a depth of O(1) meter. The surface salinity decrease is a function of wind speed and rain rate, with surface turbulence likely being an important factor in determining the formation and evolution of a fresh lens. Although it is known that both rain and wind generate surface turbulence, the relative importance of rain- and wind-generated turbulence in governing fresh lenses is an open question due to lack of field measurements of surface turbulence during rain. Direct measurement of surface turbulence and vertical profiles of salinity during rain are needed to understand whether the turbulence generated by rain in the upper few centimeters has an impact on fresh lenses generated by rain.
Asher, W., Jessup, A., Branch, R., and Clark, D. (16-Apr-13). Salinity gradients in the top few meters of the ocean surface can exist due to precipitation or evaporation. If present, they will complicate comparing salinity measured by ARGO drifters at typical depths of five meters to salinities retrieved using L-band microwave radiometers such as SMOS and Aquarius, whose measurement depths are on order of 0.01 m.
Hsu, Po-Chun; Lin, Chen-Chih; Ho, Chung-Ru (25-Apr-17). Changes of sea surface salinity (SSS) in the open oceans are related to precipitation and evaporation. SSS has been an indicator of water cycle. It may be related to the global change. The Kuroshio Current, a western boundary current originating from the North Equatorial Current, transfers warm and higher salinity to higher latitudes. It flows northward along the east coasts of Luzon Island and Taiwan Island to Japan. In this study, effects of heavy rainfall on the Kuroshio surface salinity east of Taiwan are investigated.
Boutin, J., Viltard, N., Supply, A., Martin, N., Vergely, J., Hénocq, C., and Reverdin, G.P. (24-Feb-16). The European Soil Moisture and Ocean Salinity (SMOS) satellite mission monitors sea surface salinity (SSS) over the global ocean for more than 5 years since 2010. The MADRAS microwave radiometer carried by the French (CNES) Indian (ISRO) satellite mission Megha-Tropiques sampled the 30° N-30° S region end of 2011 and in 2012, very complementary to other Global Precipitation Measurement (GPM) missions.
Supply, A., Boutin, J., Vergely, J-L., Hasson, A.E.A., Reverdin, G.P., Mallet, C., and Viltard, N. (12-Feb-18). Two L-Band (1.4GHz) microwave radiometer missions, Soil Moisture and Ocean Salinity (SMOS) and Soil Moisture Active and Passive (SMAP), currently provide sea-surface salinity (SSS) measurements. At this frequency, salinity is measured in the first centimetre below the sea surface, which makes it very sensitive to the presence of fresh water lenses linked to rain events. A relationship between salinity anomaly (?S) and rain rate (RR) is derived in the Pacific intertropical convergence zone from SMOS and SMAP SSS measurements, and the RR from the Special Sensor Microwave Imager/Sounder (SSMIS). We look at the robustness of the relationship in various areas.
Presented at the 2016 AGU Fall Meeting
Schmitt, R.W., Li, L., and Liu, T. (16-Dec-16). We have discovered that sea surface salinity (SSS) is a better seasonal predictor of terrestrial rainfall than sea surface temperature (SST) or the usual pressure modes of atmospheric variability. In many regions, a 3-6 month lead of SSS over rainfall on land can be seen. While some lead is guaranteed due to the simple conservation of water and salt, the robust seasonal lead for SSS in some places is truly remarkable, often besting traditional SST and pressure predictors by a very significant margin. One mechanism for the lead has been identified in the recycling of water on land through soil moisture in regional ocean to land moisture transfers. However, a global search has yielded surprising long-range SSS-rainfall teleconnections. It is suggested that these teleconnections indicate a marked sensitivity of the atmosphere to where rain falls on the ocean.
Skliris, N., Zika, J.D., Nurser, A.J.G., Marsh, R. and Josey, S.A. (25-Feb-16). Ocean salinity is an integrator of changes in the water cycle, reflecting the exchange of freshwater between the ocean and various components of the climate system. In this study we will use the water mass transformation framework to infer water cycle changes from salinity changes in observations and CMIP5 models.
Lagerloef, G., Kao, H-Y., and Carey, D. (29-Apr-19). Update of triple-point analysis efforts being conducted on salinity measurements. The three systems evaluated include Aquarius, in-situ data, and the HYCOM model. Future work will include a more extensive study of Aquarius Level 2 data over a longer time period.
Dennis, K.J., Carter, J.A., and Wieringa, M. (26-Feb-14). Measurements of d18O and dD in seawater and freshwater inform us about processes such as evaporation, precipitation, tidal mixing, submarine groundwater discharge and salt rejection during sea-ice formation. In this study, the authors demonstrate a continuous flow water sampler, coupled to a CRDS system, for real-time measurements of d18O and dD.
Presented at the 2018 AGU Fall Meeting
Ren, L., Xie, P., Xue, Y., Kumar, A., Boyer, T., and Bayler, E.J. (14-Dec-18). A analysis of observation-based global oceanic data, comprising pentad (5-day mean) data sets of global sea-surface salinity (SSS) and associated freshwater fluxes (precipitation (P) and evaporation (E)), is developed at the NOAA Climate Prediction Center (CPC) for real-time monitoring of sub-seasonal variations. SSS analysis, at pentad temporal resolution, is developed through blending in situ measurements from the NOAA National Center for Environmental Information (NCEI), retrievals from the European Space Agency's (ESA) Soil Moisture - Ocean Salinity (SMOS) mission, the joint U.S. and Argentinian Aquarius mission, and the National Aeronautics and Space Administration's (NASA) Soil Moisture Active-Passive (SMAP) mission.
Presented at the 2016 AGU Fall Meeting
Meissner, T. and Wentz, F.J. (16-Dec-16). Our presentation discusses the latest improvements in the salinity retrievals for both Aquarius and SMAP since the last releases. The Aquarius V4.0 was released in June 2015 and the SMAP V 1.0 was released in November 2015. Upcoming releases are planned for SMAP (V 2.0) in August 2016 and for Aquarius (V 5.0) late 2017.
Meissner, T., Wentz, F., and Lee, T. (25-Apr-17). Our presentation discusses the latest improvements in the salinity retrievals both for Aquarius and Soil Moisture Active-Passive (SMAP) since the last releases. The Aquarius V4.0 was released in June 2015. The final V5.0 release is planned for late 2017. SMAP V 2.0 has been released in September 2016. We will present validation results for both Aquarius V5.0 pre-release and SMAP V2.0 salinity comparing with near-surface salinity measurements from Argo floats. We show that salty biases at higher northern latitudes in Aquarius V4.0 can be explained by inaccuracy in the model used in correcting for the absorption by atmospheric oxygen.
Durack, P. (22-May-17). Thanks largely to a boom in measurements and data, the research focus of the oceanic arm of the global water cycle has received considerable attention over the last decade. With the high-frequency measurements provided by salinity measuring satellites, and the sea-going SPURS campaigns, the direct relationship between salinity and rainfall has been further examined. These new assessments have uncovered relationships that occur over very short time and space scales, and which are unresolved by current modeling systems. The presentation will provide an overview of current progress in understanding, and outline some ongoing work aimed at addressing the temporal disconnect between multidecadal and decadal analyses.
Estella-Perez, V., Mignot, J., Guilyardi, E., and Swingedouw. D. (07-Nov-18). Atlantic Meridional Overturning Circulation (AMOC) contributes to northward heat transport in the Atlantic, and is the primary means of heat and carbon transport from the surface to the deep ocean. This study investigates the use of sea surface salinity and sea surface temperature data to reconstruct past climate conditions in the AMOC.
Wentz, F.J. and Meissner, T. (27-Mar-12). This talk concerns the reflected galactic radiation, a large scale signal that is complex and subject to modeling errors. Complete validation of galaxy reflection tables will likely require multiple years of observations to complete.
Kao, H-Y., Lagerloef, G., and Carey, D. (16-Nov-11). A regional and global analysis of Aquarius data, using the Aquarius Validation Data Segment. The Aquarius L2/V1.2 data are compared between ascending and descending tracks along with other variables.
Yang, J., Riser, S., Nystuen, J., Asher, W., and Jessup, A. (12-Nov-14). Knowledge of the intensity and spatial-temporal distribution of rainfall over the ocean is critical in understanding the global hydrological cycle. However, rain has proven to be difficult to measure over the ocean due to problems associated with deploying rain sensors from moving platforms combined with the spatial and temporal variability of rainfall itself. Underwater acoustical rain gauges avoid the issues of surface rain sensors by using the loud and distinctive underwater sound generated by raindrops on the ocean surface to detect and quantify rainfall.
Brown, S. and Misra, S. (18-Sep-17). This presentation investigates the Aquarius drift characterization and correction approach, including recommendations for which corrections to apply to V5 data.
Melnichenko, O. and Hacker, P. (18-Sep-17). A comparison of weekly Level-3 SSS with Argo buoy data with a focus on regional differences and spurious annual/semiannual signals.The ultimate goal is to characterize and quantify systematic biases and random errors in Aquarius SSS data to optimize the utility of the data for scientific research.
Melnichenko, O. and Hacker, P. (29-Mar-16). This study compared versions of Aquarius data processing (e.g., V4.0, V4.1.0, V4.2.1) in various ways, including: box analysis (Indian and Pacific Oceans), latitude-time distributions of zonally averaged differences between Aquarius weekly maps and Argo buoy data; ascending minus descending Aquarius data (three-year mean) with respect to Argo; time-varying bias for ascending and descending data (April and September 2013); and empirical orthogonal function (EOF) decomposition of ascending and descending orbits. The conclusion is that some static and time-varying biases persist, which need to be characterized and quantified (e.g., spatial maps of amplitude and phase) for science and applications users.
Xie, X., Liu, W., Clark, E., and Xing, Y. (12-Nov-14). New river discharge data recently produced from terrestrial hydrology models and river gauge measurements, as part of the NASA Energy and Water studies, are brought together with space-based sea surface salinity measurements by Aquarius and SMOS to demonstrate the role of river discharge in salinity changes near three river mouths: the Mississippi, the Ganges, and the Amazon. The characteristics of the seasonal cycle and the year-to-year changes of the river runoff are described.
Presented at the 2014 AGU Fall Meeting
Xie, X. and Liu, W.T. (18-Dec-14). New river discharge data are brought together with spacebased sea surface salinity measurements by Aquarius and SMOS to demonstrate the role of river discharge in salinity changes near three river mouths: the Mississippi, the Ganges, and the Amazon.
Ho, D. (07-Nov-18). Mesoscale eddies were first observed in the Eastern Tropical Pacific in 1977 by an infrared sensor. However these eddies rapidly lose their temperature and chlorophyll signal as they evolve, limiting their study. SMOS, SMAP and Aquarius are useful tools to study these large mesoscale features, and the results have been shown to be coherent with other parameters. Studying the coherence between SMOS, SMAP and Aquarius reduces the effect of noise and non-physical artifacts. This study demonstrates that the variability in salinity in eddies observed in the Northeast Tropical Pacific is due to horizontal advection, and includes an export of continental water to the center of the basin.
Meissner, T. (29-Apr-19). SMAP's antenna is emissive and thus more difficult to model than Aquarius. Data from ocean and Amazon targets demonstrates that the SMAP pre-launch antenna thermal reflector model needs empirical adjustment.
Uehara, H., Kruts, A.A., Mitsudera, H. Nakamura, T., and Volkov, Y.N. (26-Feb-14). The dense shelf water (DSW) produced in the Okhotsk Sea causes the deepest ventilation and plays a key role in intermediate overturn in the North Pacific. The variability of the DSW salinity and its cause, however, has been unknown because of paucity of available data. Here, the authors present the DSW salinity variability during the period 1950-2005 analyzing a new hydrographic dataset, expanded with Russian measurements.
Presented at the 2016 AGU Fall Meeting
Yueh, S.H., Fore, A., Tang, W., and Hayashi, A. (16-Dec-16). NASA’s Soil Moisture Active Passive (SMAP) mission was launched in January 2015 to provide global mapping of soil moisture. SMAP has two instruments, a polarimetric radiometer and a multi-polarization synthetic aperture radar. The radar stopped operation on 7 July 2015. Both instruments operate at L-band frequencies and share a single 6-m rotating mesh antenna, producing a fixed incidence angle conical scan at 40⁰ across a 1000-km swath. We have analyzed all available SMAP and Aquarius data to improve the geophysical model functions, relating the L-band radar and radiometer data to ocean surface wind speed, wind direction, significant wave height and sea surface temperature.
Du, Y., Shi, J.C., Yin, X., and Xu, Y. (10-July-16). Sea surface salinity (SSS) has a profounding influence on the the exchanges of matter and energy at the air-ocean interface. It is also a driving force for ocean circulations. The capability of accurate measurement of SSS with high spatial and temporal resolution shall be a desirable boost to the global climate models. The scientific missions Soil Moisture and Ocean Salinity (SMOS) [1] and Aquarius [2] are specific to this end.
Lindsley, R., Manaster, A., Meissner, T., and Wentz., F. (29-Apr-19). Solar contamination one of many corrections applied to SMAP sea surface salinity retrievals. Presentation gives details on revised sun glint quality control flag, which increases coverage while rejecting data with solar contamination.
Soldo, Y., de Matthaeis, P., and Le Vine, D. (18-Jan-17). Presentation provides an overview of the current Radio Frequency Interference (RFI) flagging in Aquarius data. RFI flags are based on fixed thresholds, defined as the highest antenna temperatures (Ta) that are expected from natural emissions. It is important to note that reaching these thresholds result in flags only, not removal of data from Aquarius datasets.
de Matthaeis, P. and Le Vine, D.M. (23-July-17). Aquarius is an microwave active/passive sensor whose main goal is to globally estimate sea surface salinity from space [1, 2]. Two instruments, a radar scatterometer and a radiometer, operate at L-band observing the same surface footprint almost simultaneously. The sensitivity to sea surface salinity (SSS) is given by the radiometer, while the scatterometer measurements provide a correction for sea surface roughness. Although the primary objective is the measurement of SSS, the instrument combination operates continuously, acquiring data over land and sea ice as well. Radio Frequency Interference (RFI) can occur in both the radiometer and the scatterometer bands of operation, and for this reason detection and mitigation of RFI was included in the data processing of both active and passive instruments. This paper will focus on the RFI processing for the Aquarius radiometer only and provide an update on the efforts to reduce the amount of missed RFI detection.
Brown, S. (14-Nov-14). This presentation focuses on how the RFI maps are generated. The first part is identifying the location of the sources and the second part is identifying their strength. This is done iteratively by minimizing a cost function between the observed ascending-descending TB differences for each horn and a forward model of the Aquarius antenna patterns convolved with the pre-identified RFI source locations.
Chandanpurkar, H.A., Yeager, S.G., Reager, J.T., and Famiglietti, J.S. (24-Feb-16). Because of the challenges with traditional means of measuring discharge globally, effect of continental freshwater forcing on regional and global ocean processes remains highly uncertain. In this work, we provide regional analyses of discharge plumes of major river systems identified in Aquarius/SAC-D and SMOS SSS observations after removing the ocean evaporation minus precipitation (E-P) signal.
Zhu, J., Ren, L., Kumar, A., Murtugudde, R., and Xie, P. (28-Aug-18). In this presentation, we will give an update of our project supported by NASA's Ocean Salinity Science Team, by focusing on the first two tasks: (1) role of SSS in MJO predictability, and (2) development of sub-monthly SSS products.
Jones, L. and Hejazin, Y. (12-Nov-13). This paper presents an alternative independent approach for the AQ roughness correction, which is derived using simultaneous measurements from the CONAE Microwave Radiometer (MWR).
Jones, L.,and Hejazin, Y. (17-Nov-11). This talk outlines a roughness correction from salinity retrieved by the microwave radiometer (MWR).
Meissner, T. and Wentz, F. (15-Nov-11). This overview provides a summary of Aquarius Cal/Val Activities a review of results.
Meissner, T., Wentz, F., and Lee, T. (18-Jan-17). This presentation gives an overview of Remote Sensing Systems’ (RSS) SMAP salinity processing (Version 2.0). These data are batch processed each month and also available through the Physical Oceanography Distributed Active Archive Center. Details on Level 2C, 3, Release Notes, and updates from Version 1.0 are provided. Maps depict the following: antenna temperature (TA) bias for ascending minus descending orbits; TA measured minus expected; Zonal/temporal biases; reflector temperature; and land correction. Data have been validated by comparing with Argo monthly (1 degree by 1 degree) maps from Scripps Institution of Oceanography. Overall, Version 2.0 is an improvement over Version 1.0 with much reduced seasonal biases.
Presented at the 2018 AGU Fall Meeting
Manaster, A., Meissner, T., and Wentz., F.J. (14-Dec-18). Our presentation gives a detailed account of the RSS Version 3 SMAP SSS release, which is scheduled for summer 2018. This release represents several significant upgrades over the previous RSS Version 2 SMAP SSS products.
Epeloa, J., Meza, A., and Bava, J.A. (12-Nov-13). This work estimates the water vapour (WV) over the ground earth using brightness temperatures at 37 Ghz and 24Ghz which are SAC-D's observables (currently calibrated to obtain WV over the sea surface).
Bruno, L. (20-July-10). Presentation include information on CONAE's User Segment Services (CUSS); relationship between SAC-D and CUSS, including services and interfaces; kinds of products and users; and opportunities and ways to acquire products from CUSS.
Torrusio, S. (12-Nov-13). In this presentation, SAC-D PI Sandra Torrusio summarizes SAC-D news, data, products, and education and public outreach activities for the second year of satellite operation. Click here for the animation embedded on Slide 19 of her presentation, which shows the seasonal variation of wind speed (m/s) over the open ocean for four weeks of data (01-Sep-12 to 30-Sep-12) as estimated using the MWR (Microwave Radiometer).
Rabolli, M. and Torrusio, S. (13-Nov-14). After the 3rd year on orbit we are presenting the status of the instruments developed under Argentinian responsibility and of those developed by France and Italy.
Torrusio, S. (11-Apr-12). Presentation includes first data results from the SAC-D observatory instruments including: Microwave Radiometer (MWR); New Infrared Sensor Technology (NIRST); High Sensitivity Camera (HSC); Data Collection System (DCS); CARMEN-1 and ROSA.
Bruscantini, C., Grings, F., Carballi, F., Barber, M., Perna, P., and Karszenbaum, H. (09-Sep-15). Several retrieval algorithms were implemented to retrieve soil moisture and optical depth. The methodology of the Bayesian algorithm was also presented, and was contrasted with previous algorithms. Performance metrics were derived using SMOS L2 soil moisture as benchmark product.
Presented at the 2018 AGU Fall Meeting
Yu, L. (14-Dec-18). The subtropical underwater (STUW) salinity maximum is a component of the Central Waters formed by subduction of the subtropical sea-surface salinity maximum (SSS-max). In recent decades, the Atlantic Central Water is found to have become saltier, thicker, and deeper, meanwhile the SSS-max water has become saltier on the edge and fresher in the center. The pattern change at the surface seems to be different from the "dry-gets-drier-and-wet-gets-wetter" (DDWW) scenario that predicts the global water cycle intensifies under the global warming and the subtropical SSS-max should also intensify. In this study, we present observation evidence showing that the subtropical net evaporation zone has widened and weakened since 1979, and the pattern change in satellite-derived evaporation-minus-precipitation (E-P) flux is consistent with the SSS-max pattern change.
Presented at the 95th AMS Meeting
Zhu, J., Huang, B., Zhang, R.H., Hu, Z.Z., Kumar, A., Balmaseda, M.A., Marx, L., and Kinter III, J.L. (07-Jan-15). According to the classical theories of El Niño and the Southern Oscillation (ENSO), subsurface anomalies in ocean thermal structure related to thermocline displacements are precursors for ENSO events and their initial specification are essential for skillful ENSO forecast. It has also been noted that ocean salinity in the tropical Pacific (particularly in the western Pacific warm pool) can vary in response to El Niño events, but its effect on ENSO evolution and forecasts of ENSO has been less explored. Here we present evidence using a state-of-the-art prediction system that, in addition to the passive response, salinity variability may also play an active role in ENSO evolution, and thus important in forecasting El Niño events.
Levang, S. and Schmitt, R. (08-Nov-18). The Atlantic Meridional Overturning Circulation (AMOC) is a large system of ocean currents that carries warm water from the tropics northward into the North Atlantic. As the climate warms, there are predicted to be changes in the amount of freshwater input into the North Atlantic. Subpolar precipitation and ice melt are likely to increase, and the subtropical Atlantic will become saltier. This talk examines the exchange rate between subtropical and subpolar waters, and whether or not climate models support the predicted changes the AMOC from climate change.
Skliris, N., Marsh, R., Josey, S.A., Liu, C.L., and Allen, R.P. (26-Feb-14). Global hydrographic and air-sea freshwater flux datasets are used to investigate ocean salinity changes over 1950-2010 in relation to surface freshwater flux.
Vinogradova, N. and Buckley, M. (25-Apr-17). Over the past few decades, surface waters in the subpolar North Atlantic have experienced substantial fluctuations, including periods of rapid cooling and freshening alternating with the periods of enhanced warming, salinification, and decreased circulation of the gyre. Since these waters feed the North Atlantic thermohaline circulation, such changes have the potential to impact the global ocean circulation and future climate states. A number of potential causes for the observed changes have been suggested, including those related to the strength of the ocean circulation and heat transports, as well as other factors, such as anthropogenic aerosol forcing or changes in surface fluxes. Here we assess how the observed warming/salinification events fit into the long-term picture, focusing on variations in upper-ocean salinity.
Presented at the 2014 AGU Fall Meeting
Miyama, T. and Mitsudera, H. (18-Dec-14). It is known that a quasi-stationary jet-like current [referred to as J1 in Isoguchi et al. (2006)] flows along the northern part of the Kuroshio/Oyashio mixed water region in the western Pacific Ocean. Observations (Isoguchi et al. 2006, Wagawa et al. 2014) have shown that the jet transports saline water in the subtropical Pacific Ocean to the subpolar region. To investigate how the subtropical water is transported through the quasi-stationary jet, numerical particle were tracked using a high resolution ocean reanalysis dataset, the Japan Coastal Ocean Predictability Experiment (JCOPE2).
Kao, H-Y. and Lagerloef, G. (13-Nov-13). This study reveals the detailed structures and variations of salinity fronts (SF) in the tropical Pacific using Aquarius observations, specifically at the eastern edge of western Pacific fresh pool, south boundary of intertropical convergence zone (ITCZ) and the western edge of eastern Pacific fresh pool.
Lindstrom, E. (12-Nov-14). In this presentation, the author provides an introduction and overview of the Salinity Processes in the Upper Ocean Regional Study (SPURS).
Schmitt, R. (20-July-10). Presentation includes the following information about the Salinity Processes in the Upper ocean Regional Study (SPURS): science rationale; proposed locations for SPURS sites; tools for the field program; and cruise dates (i.e., U.S. and international partners).
Presented at the 95th AMS Meeting
Schmitt, R.W. (05-Jan-15). Strong trends in ocean salinity have been documented over the past 50 years that suggest an intensification of the water cycle is underway. That is, saltier areas are getting saltier and fresh areas fresher.
Jacob, M., Jones, L.W., Drushka, K., Santos-Garcia, A., Asher, W. and Scavuzzo, M. (23-July-17). Based upon research with the Aquarius (AQ) satellite remote sensor, a rain impact model (RIM) has been developed which estimates the occurrence of sea surface salinity (SSS) stratification. RIM uses global salinity (HYCOM) and rainfall (CMORPH) products to estimate the transient change in SSS due to rainfall. Previously SSS predicted by RIM have exhibited good correlations with AQ, but the choice for the duration window (24 h) was arbitrary. In this paper, we examine the effect on RIM of different time duration windows.
Meissner, T., Wentz, F., Manaster, A., and Lee, T. (25-May-17). Remote Sensing System’s (RSS) SMAP Version 2 sea surface salinity (SSS) data have been released on September 13, 2016. The release contains a Level 2 swath product and Level 3 maps of 8-day running averages and monthly averages. Our talk discusses the major steps of the SMAP salinity retrieval algorithm, including updates and improvements from the Version 1 (BETA release).
Vinogradova Shiffer, N. (06-Nov-18). Once each decade, NASA and its partners look 10 years into the future to prioritize research areas. In this presentation, the author discusses upcoming NASA Ocean Salinity Science Team opportunities, OceanObs'19 (an international, community-driven conference for communicating the decadal progress of ocean observing networks and charting innovate solutions to societal needs), the scientific and application drivers for satellite salinity, opportunities for integration, and the need for continuity and enhancement in the years ahead.
Wentz, F. and Meissner, T. (16-Nov-11). This talk includes a review of current algorithm updates, a brief description of the reflected galaxy computation, analysis of Sigma-wv and Sigma-hh, a method of removing the TB roughness component. Salinity retrieval results are also shared.
Soldo, Y., de Matthaeis, P., and Le Vine D.M. (27-Aug-18). This talk will present examples of the SMAP RFI maps and research being done on RFI detection and mitigation in support of the SMAP salinity project.
Awo, M., Alory, G., Da-Allada, C., Jouanno, J., Delcroix, T., and Baloitcha, E. (25-Apr-17). Interannual climate variability in the tropical Atlantic is dominated by two internal modes: an equatorial and a meridional mode. The equatorial mode is partly responsible for sea surface temperature (SST) anomalies observed in boreal summer in the Gulf of Guinea. The meridional mode peaks in boreal spring as an inter-hemispheric SST fluctuation. Previous studies show that these modes affect the migration of the inter tropical convergence zone which drives regional precipitation. In this study, we extracted the Sea Surface Salinity (SSS) signature of these modes from in situ data.??
Thompson, E.J. (12-Mar-18). Preliminary results from postdoc research into (1) near-surface density stratification by rain and diurnal warming; and (2) the potentially delayed and displaced mixing of freshwater into ocean mixed layering.
Nyadjro, E. and Subrahmanyam, B. (11-Nov-14). We present results on Aquarius and the Soil Moisture and Ocean Salinity (SMOS) observations of the sea surface salinity (SSS) structure during an Indian Ocean Dipole event. Comparisons with Argo data show that the satellites are able to resolve the observed SSS pattern in the Indian Ocean despite some challenges in the northern Indian Ocean.
Tesdal, J-E., Abernathey, R., Goes, J., Gordon, A.L., and Haine, T.W.N. (12-Feb-18). Examination of a range of salinity products collectively suggest widespread freshening of the North Atlantic from the mid-2000 to the present. Monthly salinity fields reveal negative trends that differ in magnitude and significance between western and eastern regions of the North Atlantic. These differences can be attributed to the large negative interannual excursions in salinity in the western subpolar gyre and the Labrador Sea, which are not apparent in the central or eastern subpolar gyre. This study demonstrates that temporal trends in salinity in the northwest (including the Labrador Sea) are subject to mechanisms that are distinct from those responsible for the salinity trends in central and eastern North Atlantic.
Sato, O. and Polito, P. (17-Apr-13). As the western boundary current in the South Atlantic subtropical gyre, the Brazil Current transports warm and salty water southward while the Malvinas Current carries colder and fresher water northward. The excursions of the Brazil Current over the southern limit of the gyre brings saltier water to that region that could undergo to intensive cooling and subsequent subduction due to loss of buoyancy.
Zhou, Y., Lang, R., Dinnat, E., and Le Vine, D.M. (29-Apr-19). Update on newest dielectric measurements: 30, 34, 35, 36 PSU at various temperatures including subzero temperatures.
Presented at the 2014 AGU Fall Meeting
Ren, L. and Bayler, E. (18-Dec-14). This study attempts to address the atmospheric and oceanic causes of sub-monthly, monthly, seasonal variability in mixed-layer salinity from observational data sets. The data sets include measurements from the Aquarius sea surface salinity, SMOS sea surface salinity, Argo profiling float data, CMORPH precipitation, OAFlux evaporation and the ocean current measurements from OSCAR.
Kao, H. and Lagerloef, G. (18-Nov-15). Due to the increased availability of data from Aquarius, SMOS satellites and Argo observations, sea surface salinity variations in the Intertropical Convergence Zone (ITCZ) have been able to be studied.
Lee, T., Lagerloef, G., Kao, H., McPhaden, M.J., and Willis, J. (26-Feb-14). Tropical Atlantic instability waves (TIWs) play an important role in the dynamics of the tropical Atlantic Ocean and related climate variability. Previous studies based on satellite-derived sea surface temperature (SST) data suggest that the signature of these waves is the strongest in the eastern-central equatorial Atlantic (around 15W). Our analysis of Aquarius sea surface salinity (SSS) indicates that these waves remain to be very energetic in the western equatorial Atlantic.
Lee, T., Lagerloef, G., McPhaden, M., Willis, J., and Gierach, M. (13-Nov-13). Tropical Atlantic instability waves (TIWs) play an important role in the dynamics of the tropical Atlantic Ocean and related climate variability. Analysis of Aquarius seas surface salinity shows that (1) tropical Atlantic TIWs remain strong in the west although the SST signature is weak; (2) the S effect on PPE is somewhat weaker than the T effect in the east, but increases dramatically towards the west where it becomes much more dominant; (3) the S effect on PPE has a direct effect (to density) and an indirect effect (due to T'S'), which is very significant; and (4) seasonality of the growth/decay of TIWs are somewhat different between east and west, probably due to the differences in processes that set up the meridional velocity shear.
McDonagh, E.L., King, B.A., Bryden, H.L., Johns, W.E., and Nurser, A.G. (26-Feb-14). In this study, the authors present a seven-year time-series of oceanic heat and freshwater fluxes across 26°N in the Atlantic between 2004 and 2011. The time series are constructed using observations from the RAPID-MOCHA array, Argo profiles and surface wind estimates from the ERA-reanalysis.
Presented at the 2014 AGU Fall Meeting
Grodsky, S., Carton, J., and Bentamy, A. (18-Dec-14). Although upwelling normally doesn't have direct impact on the sea surface salinity (SSS), we present observational evidence of upwelling-induced SSS patterns off the Pacific Central American coast.
Chao, Y. and Boutin, J. (12-Nov-14). The Aquarius and SMOS salinity satellite missions have established the Satellite & In Situ Salinity Working Group. The major goal of this working group is to improve our understanding of the link between L-band satellite (SMOS and Aquarius) remotely sensed salinity (for approximately the top 1 cm of the sea surface) and in situ measured salinity (routinely measured at a few meters depths by ships and ARGO floats but recently accessible to up to few cm depth by new profilers, and by surface drifters) and to develop practical methodologies for relating satellite salinity to other estimates of sea surface salinity.
Boutin, J., Chao, Y., Asher, W., Delcroix, T., Drucker, R., Drushka, K., Kolodziejczyk, N., Lee, T., Reul, N., Reverdin, G., Schanze, J., Soloviev, A., Yu, L., Anderson, J., Brucker, L., Dinnat, E., Garcia, A., Jones, W., Maes, C., Meissner, T., Tang, W., Vinogradova, N., and Ward, B. (17-Apr-15). Remote sensing of salinity using satellite-mounted microwave radiometers provides new perspectives for studying ocean dynamics and the global hydrological cycle. Calibration and validation of these measurements is challenging because satellite and in situ methods measure salinity differently.
Li, H., Fu, W., Chen, H., Li, C., and Zhao, H. (31-July-15). After almost 5 years of SMOS launched, accuracy of satellite SSS measurements is evaluated/validated in most areas. But in South-China Sea area (4°N-25°N, 105°E-125°E), few calibration/validation efforts is made in this area. In this paper we will validate the satellite (SMOS/Aquarius) derived SSS measurements based on moored buoys and ARGO in-situ measurements.
Presented at the 2016 AGU Fall Meeting
Potemra, J.T., Hacker, P.W.. Melnichenko, O., and Maximenko, N.A. (16-Dec-16). The straits in Indonesia allow for low-latitude exchange of water between the Pacific and Indian Oceans. Collectively known as the Indonesian Throughflow (ITF), this exchange is thought to occur primarily via the Makassar Strait and downstream via the Lombok Strait, Ombai Strait and Timor Passage. The Sunda Strait, between the islands of Sumatra and Java, is a very narrow (~10 km) and shallow (~20m) gap, but it connects the Java Sea directly to the Indian Ocean.
Bayler, E. (26-Nov-14). Satellite sea-surface salinity (SSS) observations provide broad coverage that contributes to addressing spatial and temporal gaps due to irregular observations in the in situ record. While satellite SSS retrievals continue to mature, significant differences continue between the SSS observations from the European Space Agency’s (ESA) Soil Moisture – Ocean Salinity (SMOS) mission and the joint United States and Argentine Aquarius/SAC-D mission.
Ren, L. and Bayler, E. (25-Feb-16). Comparing satellite sea-surface salinity (SSS) measurements and in situ observations reveals large-scale differences. What causes these differences? In this study, five boxes, sampling various oceanic regimes of the global ocean, provide insights on the relative performance of satellite SSS retrievals with respect to the influences of SST, precipitation and wind speed.
Vandemark, D., Feng, H., Ardhuin, F, Chapron, B., and Reul, N. (17-Nov-11). The goal of this work is to develop and refine an empirical SSS correction for long wave impacts that augment winds, Aquarius scatterometer, or other ocean roughness information.
Fore, A. (16-Nov-11). The components of the scatterometer calibration were discussed in this talk, including the bias correction factor, antenna pattern correction, and faraday rotation correction.
Freedman, A., Fore, A., Neumann, G., and Huneycutt, B. (15-Nov-11). The topic of this presentation are the Aquarius RFI products that may be of interested to the large community, a discussion of on-board RFI flagging, and an overview of the process of detecting RFI outliers and flagging them.
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A. and Tang, W. (16-Nov-11). To assess the scatterometer stability, measurements were compared to expected over three locations - open ocean, Dome-C and over the Amazon plume. The results demonstrated that the scatterometer is stable to within ~.1db over time. The difference between the ascending and descending Sigma0 over DOME-C is large, especially for Beam 1.
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A. and Tang, W. (16-Nov-11). To assess the scatterometer stability, measurements were compared to expected over three locations - open ocean, Dome-C and over the Amazon plume. The results demonstrated that the scatterometer is stable to within ~.1db over time. The difference between the ascending and descending Sigma0 over DOME-C is large, especially for Beam 1. This talk contains additional slides covering the DOME-C results.
Freedman, A. (16-Nov-11). An overview of efforts to calibrate the scatterometer temperature. For current benign space environment, it appears to be irrelevant whether temperature calibrations are used. If the environment degrades, the temperature calibration correction may have a more noticeable effect.
Freedman, A., Piepmeier, J., and Hong, L. (15-Nov-11). Full sets of Aquarius telemetry are monitored at every downloading for red and yellow outliers, which is linked to an automatic alarm system. These telemetry are viewable using web tools. There is a desire to compute and view daily averages of all telemetry items, and to be able to compute and view full sets of daily statistics for selected items.
Presented at the 2018 AGU Fall Meeting
Entekhabi, D., Yueh, S.H., O'Neill, P.E., Entin, J.K., and You, T-H. (13-Dec-18). NASA's Soil Moisture Active Passive (SMAP) mission now has completed its three-years prime-phase mission and is entering extended phase. In this presentation the science results addressing the prime-phase science requirements related to water-energy-carbon linkages over land are highlighted. Examples of SMAP data in applications (flood prediction, drought-monitoring and weather forecasts) are presented. Uses of SMAP instrument data in ocean, cryosphere and ecological sciences are also included. The presentation ends with a discussion of the new science priorities and their implementation plan for the extended phase.
Carballo, F., Masuelli, S., Salgado, H., Labanda, M., and Barreira, S. (17-Nov-15). Sea ice cover is the most important feature of the polar ocean environment and plays a key role in the balance of energy exchange between the ocean and the atmosphere, significantly involved in global climate change. Satellite microwave sensors (such as the SAC-D Microwave Radiometer) provide information about floating ice coverage, regardless of cloud and light conditions using brightness temperature.
de Matthaeis, P. (11-Apr-16). Passive microwave measurements from the Soil Moisture Ocean Salinity (SMOS) mission, operating in the L-band at a frequency of 1.41 GHz, have been used to retrieve sea ice thickness with promising results, and a daily data product is now available from the Integrated Climate Data Center of the University of Hamburg. The purpose of this work is to apply a similar technique to measurements from two other L-band passive instruments, Aquarius and SMAP. Aquarius is a NASA sensor flown aboard the Argentinean SAC-D spacecraft and also operating at L-band.
Donohue, K.A., Watts, D.R., and Kennelly, M. (19-Nov-15). Results of the cDrake experiment (2007-2011), which studied the Antarctic Circumpolar Current using an array of current and pressure recording inverted echo sounders (CPIES) are discussed.
Jones, W.L., Hejazin, Y., and El-Minri, S. (17-Sep-15). This paper provides an alternative approach using a theoretical Radiative Transfer Model (RTM) driven by numerical weather forecast model for ocean surface wind vector.
Qu, T., Song, T., and Maes, C. (13-Nov-13). This study investigates the sea surface salinity (SSS) and barrier layer variability in the equatorial Pacific using recently available Aquarius and Argo data. Conclusions are: (1) Aquarius SSS agrees reasonably well with Argo and can precisely detect the SSS front in the equatorial Pacific; (2) the SSS front nicely represents the eastern edge of the warm pool, and both of them have a strong signature of ENSO; and (3) A thick barrier layer is always present on the western side of the SSS front, moving back and forth with the ENSO cycle.
Delcroix, T., Radenac, M.H., Cravatte, S., Gourdeau, L., and Alory, G. (26-Feb-14). Small SST and SSS (an indicator of iron-rich PNG river outflows) changes in the Solomon and Bismarck Seas may be transported to the equatorial Pacific and have strong climatic and biological impacts. In this study, the authors analyze mean and seasonal changes in SSS and SST, using 1977-2012 in situ data collected from Voluntary Observing Ships.
Sommer, A., Reverdin, G.P., Kolodziejczyk, N., and Boutin, J. (24-Feb-16). Sea surface salinity (SSS) is investigated in the subtropical North Atlantic Ocean during the Subtropical Atlantic Surface Salinity Experiment Strasse/SPURS in August 2012 - September 2013. During this experiment, more than 100 drifters were deployed providing measurements of temperature, salinity and 15m depth currents.
Presented at the 2018 AGU Fall Meeting
Garcia-Eidell, C., Comiso, J.C., Dinnat, E., and Brucker, L. (12-Dec-18). Sea surface salinity (SSS) retrieved from the Aquarius and Soil Moisture and Ocean Salinity (SMOS) satellites were compared with quality-controlled measurements from ship, floats, moored buoys and others to evaluate the accuracy of satellite-derived SSS data in the Southern Ocean. Latest versions of the Aquarius official release, Combined Active-Passive product, weekly polar-gridded product, as well as the SMOS BEC Objectively-Analyzed L3 product were used and results show root-mean-square error values with respect to in-situ measurement ranging from 0.25 to 0.58 psu.
Yu, L. (26-Feb-14). Evidence from Aquarius and SMOS suggests that the spatial distribution of sea surface salinity in low-salinity basins has different characteristics.
Tranchant, B., Gernier, E., Garric, G., Drevillon, M., and Reginer, C. (27-Nov-14). Improving the SSS (Sea Surface Salinity) constrain at various scales is an important issue for ocean forecasting. It concerns the short term meso-scale and the seasonal anomalies. Both strongly depend on the surface freshwater budget (evaporation, precipitation and runoff). Presently, it is not yet possible to fully remove SSS biases with the poorly sampled Argo network data near the surface (depth <5m). It encourages us to find the best way to deal with SSS data observed from space (SMOS and Aquarius).
Presented at the 2016 AGU Fall Meeting
Ruiz-Etcheverry, L., Maximenko, N.A., and Melnichenko, O. (07-Nov-17). Marine fronts are narrow boundaries that separate water masses of different properties. These fronts are caused by various forcing and believed to be an important component of the coupled ocean-atmosphere system, particularly in the tropical oceans. In this study, we use sea surface salinity (SSS) observations from Aquarius satellite to investigate the spatial structure and temporal variability of SSS fronts in the tropical Atlantic.
Lee, J., de Matthaeis, P., Yueh, S., Hong, C., Lee, J., and Lagerloef, G. (11-Nov-14). This study demonstrates that the spaceborne Aquarius instrument is able to monitor the sea surface salinity variations in the East China Sea with the spatial resolution of about 150 km at 7-day interval, where routine observations are difficult.
Awo, M., Alory, G., Da-Allada, C., Delcroix, T., Jouanno, J., and Baloïtcha1 E. (07-Nov-18). In the tropical Atlantic, sea surface temperature and surface winds are affected by seasonal weather modes that bring changes to winds, currents, and temperature patterns. Both modes affect the amount of precipitation that falls in the region, and should be observable in the sea surface salinity signal. The salinity observations of were compared to model data of time periods in each mode, to determine their level of agreement and to investigate the processes responsible for the observed signatures. SMOS satellite data were able to identify the signature of these interannual climatic modes, and may be useful in filling gaps in where in situ data are not available.
Guan, B., Halkides, D.J., Lee, T., and Waliser, D.E. (26-Feb-14). Sea surface salinity (SSS) measurements by the Aquarius satellite are analyzed along with precipitation and sea surface temperatures to characterize and understand the SSS signature of the Madden-Julian Oscillation (MJO) over the 2-yr period for which Aquarius data are currently available. Aquarius data are able to capture the SSS signature of MJO.
Presented at the 2014 AGU Fall Meeting
Boutin, J., Martin, N., Reverdin, G.P., Morisset, S., Yin, X., Centurioni, L., and Reul, N. (18-Dec-14). The Soil Moisture and Ocean Salinity (SMOS) mission monitors sea surface salinity over the global ocean for more than 4.5 years. The objective of this presentation is 1) to analyse the signature of rainfall on SMOS salinity and 2) to validate it. This is a challenging task given that SMOS measures the salinity in the first top centimeter while most in situ measurements of salinity are made at a few meters depth and that other effects than sea surface salinity may affect the radiometric signal, like sea surface roughness modified by rain drops and rain atmospheric effects.
Qu, T. (11-Nov-14). This study investigates the sea surface salinity (SSS) variability in the equatorial Pacific using recently available Aquarius and Argo data. For the period of observation from August 2011 to present, Aquarius nicely resolves the SSS front and its zonal displacement along the equator.
Schumann, G.J., Andreadis, K.M., Fararra, J., Moller, D.K., and Chao, Y. (26-Feb-14). Recent sea surface salinity measurements from the Aquarius satellite provide a unique opportunity to reveal the sea surface salinity variability in response to the Congo River discharge. Both the long-term climatology from the World Ocean Atlas and the vertical salinity profiles measured by the Argo floats during the recent decade are used to interpret the Aquarius data.
Presented at the 2014 AGU Fall Meeting
Kim, S., Lee, J., de Matthaeis, P., Yueh, S.H., Hong, C., Pang, I., and Lagerloef, G.S.E. (18-Dec-14). This study demonstrates that the spaceborne Aquarius instrument is able to monitor the sea surface salinity variations in the East China Sea, where routine observations are difficult.
Presented at the 2018 AGU Fall Meeting
De Morais Chiossi, P. and Sato, O.T. (10-Dec-18). Observations of the temporal and spatial variability of the South Atlantic Ocean are of great scientific interest due to its influence on the regional weather and global climate through the Meridional Overturning Circulation (MOC). These changes directly affect society through variations in the pattern of rain, humidity, heat flux, and wind patterns. Despite this, there are still many gaps in understanding the full implications and impacts of ocean variability. The salinity is one of the least understood, mainly due to the absence of broad and long-term sustainable in situ data in the South Atlantic. Although, this has been changing lately with the surge of satellite missions designed to measure surface salinity, along with the increase of active Argo profilers.
Boutin, J., Reverdin, G., Febtin, N., Yin, X., and S. Morisset (26-Feb-14). The SMOS mission has been monitoring sea surface salinity over the global ocean for almost four years. After reviewing the large-scale accuracy of SMOS sea surface salinity, the authors focus on the variability at shorter scales than the ones sampled by the ARGO array of floats.
Lee, T. and Fournier, S. (28-Aug-18). Variations of sea surface salinity (SSS) in the southeast Asian Seas (SEAS) have important implications to ocean circulation and climate variability. Systematic monitoring of salinity changes in the SEAS region has been extremely challenging due to the complicated geometry and other factors. This has hindered our understanding of freshwater changes in the SEAS region, the relationships with climate variability (e.g., monsoon, El Niño-Southern Oscillation, and Indian Ocean Dipole), and the potential implications to climate predictions.
Dinnat, E.P., Le Vine, D.M., Boutin, J., and Meissner, T. (23-July-17). We present comparisons between satellite sea surface salinity products from the SMOS, Aquarius and SMAP missions and assess some of the reasons for the observed differences.
Banks, C.J., Gommenginger, C.P., Srokosz, M.A., and Snaith, H.M. (26-Feb-14). The UK National Oceanography Centre (NOC) has produced monthly 1 degree Level 3 SSS data products (L3) for SMOS and Aquarius based on Level 2 (L2) data (using ESA operational v5_50 and V2.0 respectively). Similar results have been reported on before using earlier versions of L2 data but are now also joined by products of different spatial/temporal resolutions.
Dinnat, E. and Le Vine, D.M. (16-Apr-13). The ESA Soil Moisture and Ocean Salinity (SMOS) mission and the NASA Aquarius instrument share the common scientific objective of mapping the global Sea Surface Salinity. To that end, they both use radiometers at L-band to measure microwave emission from the sea surface.
Meissner, T. and Wentz, F. (29-Mar-16). This presentation focused on Aquarius V4.1 ("instrument only calibration"), which shows spurious annual signal (plus drift after October 2014 in some of the channels). The approach taken was to go back to V4.0 (ocean calibration, global HYCOM) and analyze seasonal and regional biases. Various components were investigated: inter-beam differences, Aquarius versus SMAP (Soil Moisture Active Passive), galactic reflection, surface roughness correction, dependence on residual sea surface temperature and wind (speed, direction), ancillary sea surface temperature input, and air-sea temperature differences. The conclusion was that the spurious annual signal is likely instrument related.
Strub, P.T., Matano, R.P., James, C., Combes, V., Piola, A., Palma, E., Saraceno, M., Guerrero, R., Fenco, H., and Ruiz Etcheverry, L. (19-Nov-15). The seasonal circulation is described over the wide continental shelf in the SW Atlantic Ocean (27°-43°S) during 2001-2012.
Wilson, E.A. and Riser, S. (26-Feb-14). In this study, we attempt to construct a seasonal freshwater budget using output from the Hybrid Coordinate Ocean Model. In particular, we investigate the relative importance of boundary currents, vertical mixing, and large scale Ekman pumping in maintaining a closed freshwater budget.
Presented at the 2018 AGU Fall Meeting
Feng, Y. and Menemenlis, D. (14-Dec-18). River plume dynamics generated considerable research interests for the past decade due to the important role in coastal ecology, biogeochemistry, shoreline morphology and climate. Previous investigators have utilized satellite ocean color or configured regional models in studying the dispersal of river plumes, with focusing on a certain continental shelf. In this study, we used high-resolution satellite sea surface salinity (SSS) observations and a globally configured 18-km resolution, eddy permitting model (ECCO2) with the river source improvement to investigate seasonal variability of river plumes at three continental shelves, namely the Northern Brazilian (NB) Shelf, the Northern Angola (NA) Basin, and the Texas-Louisiana (TL) Shelf.
Lagerloef, G.S.E., Kao, H-Y., and Carey, D. (12-Feb-18). An important scientific goal for satellite salinity observations is to document oceanic climate trends and their link to changes in the water cycle. This study is a re-examination of seasonal to interannual sea surface salinity (SSS) variations from more recent analyses of V5.0 reprocessing of the Aquarius satellite data, Sep 2011 to May 2015. Sensor calibration over these time scales has been a concern, and the V5.0 includes improved calibration reference data compared to previous versions, which will be explained.
Presented at the 2016 AGU Fall Meeting
Lagerloef, G.S.E. and Kao, H-Y. (16-Dec-16). Salinity variations at the ocean surface are key indicators of changes in air-sea water fluxes. The Aquarius mission measured sea surface salinity (SSS) over the global ocean from 25 August 2011 to 7 June 2015 (about 3 years, 9 months), coinciding with the onset of the 2015 El Niño. This presentation will explore preliminary findings of the SSS seasonal to interannual variability during this time, and the correlations with ENSO indices, surface precipitation and evaporation fluxes.
Kao, H. and Lagerloef, G. (11-Nov-14). The Pacific Intertropical Convergence Zone (ITCZ) is a zonal band of atmospheric convective instability, clouds and rainfall near the equator. High-resolution sea surface salinity measurements from the Aquarius satellite reveals more detail in the band of lower salinity and a sharp front that aligns with the strong ITCZ atmospheric convection.
Susanto, R.D., Setiawan, A., Sulistyo, B., Adi, T.R., Agustiadi, T., Treggono, M., Triyono, A., Kuswardani, A. (19-Sep-17). To test the limit of satellite salinity performances, different satellite SSS products were compared with in situ observations in the challenging region of the Indonesian seas. In these areas, sustainable in situ observation is expensive and difficult, and it is desirable to find altearntive ways to measure water transport and flux. Ultimately, understanding the freshwater and salinity variability in this area will prove very important to global ocean circulation and climate.
Melnichenko, O. and Hacker, P. (17-Jan-17). The presentation begins with a series of analyses focused on regional and/or seasonal biases in Aquarius sea surface salinity (SSS). Various processing versions of Aquarius SSS data (e.g., V4.5.0 and V4.5.1) are compared with Argo buoy data from the Asia-Pacific Data-Research Center (APDRC). Analyses include: (1) Box analysis of regions in the Pacific and Atlantic; (2) Three-year mean global data; (3) Latitude-time distributions of weekly data (zonally averaged and time-varying); and (4) Amplitude of annual and semi-annual cycles in the bias field. The talk concludes with comparisons between Aquarius and SMAP-derived SSS data.
Presented at the 2016 AGU Fall Meeting
Nonaka, M., Hosoda, S., and Schneider, N. (16-Dec-16). With accumulation of salinity observational data by Argo floats, it becomes possible to investigate salinity variability on seasonal to interannual time scales. While we know that there is strong seasonality in sea surface temperature (SST), seasonality in sea surface salinity (SSS) is not known well. Based on gridded Argo and other observational data and atmospheric reanalysis data, we examine global distribution of SSS seasonality using 12-month lagged auto-correlation map.
Zhou, Y., Lang, R.H., Utku, C., and Le Vine, D. (17-Sep-15). In this paper, a new seawater dielectric model function is introduced including the latest permittivity data for seawater with salinity 33 psu. Finally, the validation of the end-effect, measurement variance and data fitting will be discussed.
Menezes, V.V. (28-Aug-18). The Arabian Sea exhibits the highest salinity of the Indian Ocean with values above 36.5 (psu), being a source of salt for the entire basin in several time scales. Despite the Arabian Sea to be a central region to understand the salinity dynamics of the Indian Ocean, the time scales of variability of sea surface salinity (SSS) in this region is not fully known due to the historical lack of in situ observations in basin scale with relatively high temporal resolution. In the present work, Aquarius and SMAP satellite and Argo SSS data are used to characterize these scales.
Bayler, E.J., Nadiga, S., Mehra, A., and Behringer, D. (26-Feb-14). Recently available, satellite sea-surface salinity (SSS) fields provide an important new global data stream for assimilation into ocean forecast systems. Here, the authors present results from assimilating SMOS and Aquarius SSS data into NOAA's operational MOM4.
Emberton, S., Chittka, L., Cavallaro, A., and Wang, M. (17-Apr-15). Accurate correction of the corrupting effects of the atmosphere and the water's surface are essential in order to obtain the optical, biological and biogeochemical properties of the water from satellite-based multi- and hyper-spectral sensors. The major challenges now for atmospheric correction are the conditions of turbid coastal and inland waters and areas in which there are strongly-absorbing aerosols.
Lagerloef, G., Piepmeier, J., Hong, L. and Gales, J. (29-Jan-13). Presentation gives an overview of the basic matrix formulation, regression model, global ascending and descending data from Aquarius channel 1V, computed instrument and geophysical errors for all six channels.
deCharon, A.V., Companion, C.J., and Cope, R.E. (26-Feb-14). NASA's Aquarius instrument and Salinity Processes in the Upper Ocean Regional Study (SPURS) have given the scientific community unprecedented insight into salinity's role in the earth system. Complementary public engagement efforts have focused on themes of the water cycle, ocean circulation and climate.
Matano, R.P., Combes, V., Piola, A.R., Guerrero, R., Palma, E.D., Strub, P.T., James, C., Fenco, H., Chao, Y., and Saraceno, M. (19-Nov-15). A high-resolution model is used to characterize the dominant patterns of sea surface salinity (SSS) variability in the southwestern Atlantic region.
Guerrero, R.A., Piola, A.R., Fenco, H., Matano, R.P., Combes, V., Chao, Y., James, C., Palma, E.D., Saraceno, M., and Strub, P.T. (19-Nov-15). Satellite sea surface salinity (SSS) data from Aquarius and SMOS reveal intense shelf-open ocean exchanges in the western South Atlantic. A strong seasonal SSS pattern is modulated by the seasonality of the along-shelf component of the wind stress over the shelf. However, the precise location of the export of shelf waters depends on offshore circulation patterns.
Melnichenko, O., Maimo, A.M.A., Maximenko, N.A., Hacker, P.W., and Potemra, J.T. (24-Feb-16). A persistent signature of transient mesoscale eddies in sea surface salinity (SSS) is revealed by analyzing the relationship between satellite SSS and sea surface height (SSH) variability. The SSS fields used in the study are Aquarius SSS optimum interpolation analysis recently developed at the University of Hawaii.
Silvestri, M., Randazzo, D., Buongiorno, M.F., and Musacchio, M. (12-Apr-12). Presentation gives an overview of: Volcanic thermal phenomena characteristics and monitoring capability of current earth-observing missions; first results of simulation data; ten years of thermal analysis of volcanoes; and Italian Space Agency pre-operative project for volcanic risk management.
Clayson, C.A., St. Laurent, L., and Schmitt, R. (27-Feb-14). In this presentation, the authors evaluate the upper ocean stability structure and its effect on mixing processes during several regimes occurring during the SPURS experiment using a combination of modeling and measurements from buoy and glider measurements.
Drushka, K. and Asher, W. (24-Feb-16). Fronts, eddies, filaments, upwelling, and freshwater input from rainfall, rivers, and ice-melt can all generate submesoscale to mesoscale variations in sea surface salinity. Knowledge about the horizontal variability of surface salinity is valuable for understanding ocean surface dynamical processes.
Chickadel, C., Drushka, K., Asher, W., Thompson, E., Gaube, P., and Jessup, A. (24-May-17). High-resolution thermal imagery captured from a shipboard infrared camera during the SPURS 2 experiment shows development of small-scale skin temperature variability. These centimeter to meter wavelength features are typically elongate and linear, similar to classic Langmuir cells.
Gomez-Valdes, J. and Vazquez, J. (12-Feb-18). Data from NASA's Soil Moisture Active Passive Mission (SMAP) and from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) were used to examine the freshening that occurred during the Northeast Pacific Warming of 2014-2016. Overall the freshening was found to be related to the warming and the weakening of coastal upwelling.
Jacob, M.M., Santos-Garcia, A., and Jones, L. (25-Feb-16). Previous studies have demonstrated significant differences between satellite and in-situ salinity measurements during rain. In the presence of precipitation, salinity stratification exists near the sea surface, which nullifies the presumption of a well-mixed salinity. This paper describes the Rain Impact Model (RIM) that simulates the effects of rain accumulation on the SSS applied to SMAP.
Presented at the 2018 AGU Fall Meeting
Bulusu, S. (14-Dec-18). Indian Southwest monsoon (or Summer monsoon) has strong intraseasonal oscillations in the form of active and break spells of monsoon rainfall within the monsoon season. These Intraseasonal oscillations (ISOs) are a critical driver of air-sea fluxes in the Indian Ocean. The impacts of ISOs at three major periodicities (30-90 days, 10-20 days, and synoptic 3-7 day periods) were investigated using satellite-derived estimates of sea surface salinity (SSS) from NASA's Soil Moisture Active Passive (SMAP) mission.
Fore, A., Yueh, S., Tang, W., and Hayashi, A. (25-May-17). The Soil Moisture Active Passive (SMAP) mission was launched January 31st, 2015. It is designed to measure the soil moisture over land using a combined active / passive L-band system. Due to the Aquarius mission, L-band model functions for ocean winds and salinity are already mature and may be directly applied to the SMAP mission. In contrast to Aquarius, the higher resolution and scanning geometry of SMAP allows for wide-swath ocean winds and salinities to be retrieved. In this talk we present the SMAP Sea Surface Salinity (SSS) dataset and algorithm.
Schanze, J.J., Kao, H-Y., Carey, D., and Lagerloef, G.S.E. (30-Apr-19). The "Salinity Snake" instrument was developed to sample undisturbed seawater in situ from a 13-meter boom. Thus far, it has collected about 40,000 km of very-near surface salinity data, which is used to assess satellite sub-footprint variability. In addition, data from various instruments (Argo floats, moorings, drifters, etc.) has prompted several recommendations on match-up approaches between satellites and in-situ sensors (e.g., search radius, temporal windows).
Misra, S. and Brown, S. (27-Aug-18). We will present a summary of the SMAP radiometer calibration activities undertaken by the SMAP science team and project team for the recent Version 4.0 data release. SMAP recently completed three years of operation in space with a fairly stable daily average NEDT of 0.96 K and an overall drift of less than 0.1K.
Grodsky, S.A., Vandemark, D., Feng, H., and Levin, J. (06-Nov-18). Satellite salinity from the Soil Moisture Active Passive (SMAP) mission and in situ observations were used to diagnose the source of a significant increase in warm and salty surface water entering the Gulf of Maine in the winter of 2017-2018. SMAP salinity anomaly data indicate that this event was related to a salty feature that moved along the northwestern Atlantic shelf break from near the Grand Banks southwest towards the Gulf of Maine over eight months before entering the Gulf in December 2017 to January 2018. Future work will focus on modeling and data synthesis to understand the dynamics of this particular intrusion and quantify the role of Gulf Stream meanders.
Mecklenburg, S. (15-Apr-13). Overview and objectives of the 2013 SMOS & Aquarius Science workshop.
Presented at the 2012 AGU Fall Meeting
Cabot, F., Kerr, Y.H., Anterrieu, E., and Lagerloef, G.S.E. (03-Dec-12). In early November 2012, the SMOS mission will be celebrating 3 years in orbit. Since its launch, this mission has given many opportunities for breaking new grounds. Due to the very specific way in which it acquires brightness temperature measurements of the surface, advances were made in operating a two dimensional interferometric radiometer from space, and all the processing that is needed to reach satisfying accuracy requirements.
Subrahmanyam, B., Nyadjro, E., and Felton, C. (17-Apr-13). The non-availability of global-scale salinity observations has been a challenge in many studies that require salinity data. The Aquarius salinity mission is currently providing complete global coverage of sea surface salinity (SSS) measurements with a temporal resolution of 7 days. In this study, we assess the validity of preliminary Aquarius salinity measurements in the Indian Ocean.
Boutin, J., Yin, Martin, N., Dinnat, E., Yueh, S., Reverdin, Coll G., Alory, G., and Gaillard, F. (12-Apr-12). Conclusions include: for Soil Moisture and Ocean Salinity (SMOS) sea surface salinity data, precision at 100x100km^2 over 10 days is about 0.3 in non-rainy tropical-subtropical regions far from land; there is freshening with respect to in-situ sea surface salinty (at 5m depth) in rainy conditions, suggesting a need for surface drifters to validate; Argo is very useful for large-scale validation; ship-borne thermosalinographs are very useful for validating 'small scale' (<200km) variability (gradients) seen by SMOS; etc.
Boutin, J., Hernandez, O., Reverdin, G., Gaillard, F., Reul, N., Martin, N., and Morisset, S. (16-Apr-13). The ESA/SMOS (European Space Agency/Soil Moisture and Ocean Salinity) satellite mission provides new measurements of the Sea Surface Salinity (SSS) using L-band interferometric radiometry since end of 2009. It is the first time that this technology is used for measuring SSS from space, providing global ocean coverage every 3 to 5 days and a spatial resolution of up to 40km.
Boutin, J. (19-Sep-17). This talk outlines a new method for mitigating SMOS systematic errors, and provides comparisons between SMOS salinity data and data from ship, moorings, the Argo interpolated field and SMAP.
Boutin, J., Vergely, J-L., Marchand, S., D'Amico, F., Hasson, A.E.A., Kolodziejczyk, N., Reul, N., and Reverdin, G.P. (12-Feb-18). A main contribution of satellite Sea Surface Salinity (SSS) is the spatio-temporal monitoring of fresh water plumes at mesoscale. In case of the Soil Moisture and Ocean Salinity (SMOS) satellite mission, this monitoring was often hampered due to the land-sea contamination of the SMOS interferometric measurement. Kolodziejczyk et al. (2016) developed a methodology to mitigate the SMOS systematic errors in the vicinity of continents, using self-consistency properties of SMOS SSS, that greatly improved the quality of SMOS SSS but the very fresh SSS anomalies remained often overestimated.
Martín-Neira, M., Corbella, I., Torres, F., Kainulainen, J., Olivia, R., Closa, J., Cabot, F., Castro, R., Barbosa, J., Gutierrez, A., Anterrieu, E., Tenerelli, J., Martín-Porqueras, F., Buenadicha, G., Delwart, S., Crapolicchio, R. (15-Apr-13). ESA's Soil Moisture and Ocean Salinity (SMOS) mission has been in orbit for already over 3 years which has allowed the calibration and data processing team consolidating both the calibration strategy and the Level-1 processor which transforms the raw visibility samples into polarimetric brightness temperature images.
Reul, N. and SMOS Team Members (15-Apr-13). In this talk, the authors present an overview of the SMOS mission status with respect to oceanic observations.
Sabia, R., Reul, N., Guimbard, S., Mecklenburg, S., and Laur, H. (29-Aug-18). The SMOS Pilot Mission Exploitation Platform (Pi-MEP) for Salinity is an ESA initiative to support and widen the uptake of Soil Moisture and Ocean Salinity (SMOS) mission data over the ocean.
Guimbard, S., Reul, N., Herlédan, S., Hanna, Z.E.K., Piollé, J-F., Paul, F., and Sabia, R. (06-Nov-18). The Soil Moisture and Ocean Salinity (SMOS) mission was launched on November 2, 2009 as the second Earth Explorer Opportunity mission within ESA's Living Plant Program. It has been providing brightness temperature data in L-Band continuously since January 2010, which are used to retrieve soil moisture and sea surface salinity data over land and ocean, respectively. This presentation provides a status of the Pilot Mission Exploitation Platform (Pi-MEP), which focusses on ESA's SMOS mission and supports enhanced validation and scientific process studies over the ocean.
Sabia, R., Mecklenburg, S., Reul, N., Guimbard, S., and Laur, H. (25-May-17). The recent SMOS Pilot-Mission Exploitation Platform (Pi-MEP) project principal objective will be to perform a systematic assessment of SMOS SSS data quality (at L2, L3 & L4) by systematically compare each product with relevant in situ data (ARGO, TSG, moorings, drifters...). In this talk, the current state of the initial phase of the Pi-MEP project regarding the collected datasets, visualization and extraction tools and a non-exhaustive list of oceanographic process studies will be presented.
Durand, F., Alory, G., and Reul, N. (17-Apr-13). The Indian Ocean Dipole (IOD) is the dominant mode of interannual climate variability in the equatorial Indian Ocean. It consists of a basin-scale modification of the upper ocean thermal structure, associated with drastic changes in the rainfall patterns.
Guimbard, S., Font, J., Ballabrera, J., Turiel, A., Martinez, J., Portabella, M., Gourrion, J., and Perez, F. (12-Apr-12). Conclusions include: European Space Agency is being provided Soil Moisture and Ocean Salinity (SMOS) Level 2 sea surface salinity products; Level 3 & 4 products are provided by the Spanish Data Processing Centre & Centre Aval de Traitement des Données (CATDS); at the Barcelona Expert Centre, new data fusion algorithm for Level 4 products based on singularity exponents; and the synergy SMOS/Aquarius can begin.
Kolodziejczyk, N., Hernandez, O., Boutin, J., and Reverdin, G. (26-Feb-14). The seasonal variability of the surface horizontal thermohaline structure is investigated in the subtropical and tropical north Atlantic Surface Salinity Maximum at length scales from 5-10 km to more than 500 km.
Presented at the 2012 AGU Fall Meeting
Boutin, J., Martin, N., Reverdin, G P., and Yin, X. (03-Dec-12). The ESA/SMOS (European Space Agency/Soil Moisture and Ocean Salinity) satellite mission provides measurements of the Sea Surface Salinity (SSS) using L-band interferometric radiometry since end of 2009. It is the first time that this technology is used for measuring SSS from space, providing global ocean coverage every 3 to 5 days and a spatial resolution of up to 40km. In this presentation, we first assess the accuracy of the SMOS SSS recently reprocessed by ESA (version 5), and then illustrate the additional information these new satellite products bring, with respect to in situ measurements, for ocean surface processes studies.
Li, B., Mehra, A., and Bayler, E.J. (25-Feb-16). Satellite sea-surface salinity (SSS) observations provide a new means for constraining an important state parameter in numerical ocean models. The benefits of assimilating satellite SSS observations include improved model surface density, near-surface convection, and thermohaline circulation.
Olmedo, E., Campuzano, F., Turiel, A., Oliveira, P.B., and Angélici, M.M (07-Nov-18). The LAMBDA project aims to improve the Copernicus Marine Environment Monitoring Service's Monitoring Forecast Centers thermohaline circulation models in coastal areas. This will be accomplished through better characterizing the land-marine boundary conditions, with special attention to salinity, and through watershed numerical modeling and coupling it to mesoscale regional ocean models. This talk looks at SMOS salinity data compared to model data in the Mediterranean Sea. Overall, the model and SMOS are in good agreement of the major features of the salinity dynamics, though SMOS does not capture the variability present in coastal pixels and can be affected by RFI. Future work will focus on improving the SMOS coastal data and and strengthening the mode's land-marine boundary conditions.
Alvera-Azcarate, A., Parard, G., Barth, A., and Beckers, J. (24-Feb-16). Sea surface salinity (SSS) has been measured by the Soil Moisture and Ocean Salinity (SMOS) satellite mission since 2010, providing unprecedented information about the spatial and temporal variability of salinity at the ocean surface. An analysis of daily SSS from the SMOS satellite mission using DINEOF (Data Interpolating Empirical Orthogonal Functions) is presented for the North Atlantic Ocean in 2013.
Schanze, J. (17-Jan-17). The “Salinity Snake,” which measures salinity at 1-2 cm depth, was field tested during the first Salinity Processes in the Upper-ocean Regional Study (SPURS I) campaign in the North Atlantic (Sep. 2012). The improved snake was used in the SPURS II field program in the tropical western Pacific (summer 2016). This presentation provides eight examples of freshwater lenses sampled during SPURS II under various environmental conditions (e.g., wind speeds, precipitation rates, layered and mixed seawater). Thus far, 50 freshwater lenses have been identified and half of these occured in the absence of recorded precipitation. One conclusion is that low surface salinity is heavily dependent on surface mixing.
Schanze, J.J., Lagerloef, G., Schmitt, R.W., and Hodges, B.A. (14-Nov-13). As part of the Salinity Processes in the Upper Ocean Regional Study (SPURS), a novel sea surface salinity sampling apparatus was deployed aboard the R/V Endeavor to sample undisturbed water outside of the ship's wake. The results indicate that (1) surface salinity enhancements are interesting, but probably not relevant to Aquarius retrievals; and (2) puddles can occur at any time of day and are likely of some relevance to Aquarius retrievals. Next steps include: (1) modeling the development and breakdown of surface T/S changes (PWP model); (2) gathering more data in puddles; and (3) estimating impacts on Aquarius Cal/Val.
Schanze, J.J., Lagerloef, G., Schmitt, R.W., and Hodges, B.A. (27-Feb-14). As part of the Salinity Processes in the Upper Ocean Regional Study (SPURS), a novel sea surface salinity sampling apparatus was deployed aboard the R/V Endeavor.
deCharon, A. (29-Apr-19). Updates to the "NASA Salinity" website and examples of communication materials are presented to spark discussion of OSST outreach support.
Kerr, Y. (20-July-10). Presentation gives an overview of the European Space Agency's SMOS mission, which was successfully launched in November 2009. In summary: SMOS provides very good data, earlier and better than expected; preliminary soil moisture retrievals are looking very good even though still in calibration/validation phase; and salinity maps are useful for Aquarius although radio frequency interference is an issue.
Bruscantini, C.A., Grings, F.M., and Karszenbaum, H. (18-Nov-15). Throughout the operational life of the Aquarius instrument, an alternative soil moisture product has been developed. An Observing System Simulation Experiment (OSSE) for Aquarius was developed to assess the impact of sources of errors in the soil moisture retrieval.
Karszenbaum, H., Goniadzki, D., Salio, P., Goniadzki, D., Serafini, C., and Rivas-V.Venturini, R. (19-July-10). Overviews of several projects including: La Plata Basin floods and droughts, contribution of microwave remote sensing in monitoring and prediction; flooding in the Del Plata Basin - Paraguay/Paraña wetlands corridor; soil moisture retrieval in Chaco Forest; development of techniques to detect and estimate deep moist convection; etc.
Salgado, H., Carrascal, C., Masuelli, S., and Barreira, S. (12-Nov-13). Detection of the ice that covers the marine surface in polar areas is of great interest for studies and monitoring of the climate and environment in high latitudes. Surface cover emissivity at the frequencies of 36.9 GHz and 23.5 GHz, captured by the SAC-D Micro Wave Radiometer (MWR), allows the estimation of the sea ice concentration (IC), applying algorithms adapted for this system.
Piola, A.R., Palma, E.D., and Saraceno, M. (17-Nov-15). A project summary for project 1 - South Atlantic Circulation and Salinity: An Integrated Observational and Modeling Investigation. The above project led to 11 peer-reviewed publications, 3 congress article and 28 congress and workshop presentations.
Palma, E.D. and Matano, R.P. (19-Nov-15). We characterize the low frequency variability of the South Atlantic circulation using 50 years of data from the SODA model.
Garzoli, S.L. (19-Nov-15). Until recently, most Atlantic Meridional Overturning Circulation (MOC) observing programs have focused on the North Atlantic. However, recent model analyses have suggested that critical water mass changes to the upper and lower limbs of the MOC occur in the South Atlantic.
Presented at the 2016 AGU Fall Meeting
Bingham, F. and Lee, T. (16-Dec-16). Using Aquarius Version-4 data, we have investigated the time and space scales of sea surface salinity (SSS) over the global ocean between 60°S and 60°N. Decorrelation time scales of SSS were found to be divided among less than 80 days (covering 1/2 of ocean area), 80-100 days (1/3) and greater than 100 days (remainder). Once the seasonal cycle is removed, shorter time scales (less than 80 days) dominate.
Melnichenko, O., Hacker, P., and Meissner, T. (27-Aug-18). The Soil Moisture Active Passive (SMAP) satellite based version V2.0 SSS data delivered by Remote Sensing Systems (RSS) are evaluated against in situ salinity from Argo buoy measurements. To assess the effect of smoothing, two versions of the data have been evaluated- the so-called 40-km and 70-km resolution products. The difference statistics are computed by comparing Argo buoy measurements for a given week with SSS values at the same locations obtained by interpolation of the corresponding Level-3 SSS maps.
Melnichenko, O., Hacker, P., Maximenko, N., and Potemra, J. (26-Mar-12). Are small scale features real, and to what degree are they a product of ascending/descending and inter-beam biases?
Presented at the 2014 AGU Fall Meeting
Mannshardt, E., Sucic, K., Bingham, F., and Fuentes, M. (18-Dec-15). Salinity is an indicator of the interaction between ocean circulation and the global water cycle, which in turn affects the regulation of the Earth's climate. Due to its fine spatial and temporal coverage, Aquarius presents an ideal measurement system for fully characterizing the distribution and properties of sea surface salinity. This leads to the need for the proper validation of the Aquarius salinity product with independent salinity measurements. Using the first two years of Aquarius 3.0 Level 2 sea surface salinity data we investigate time and space scales of variability and trends.
Presented at the 2016 AGU Fall Meeting
Maes, C., O'Kane, T., and Monselesan, D.P. (16-Dec-16). Despite recent advances in satellite sensors, it remains great uncertainty in the large-scale spatial variations of upper ocean salinity across seasonal through interannual to decadal timescales. Consonant with both broad-scale surface warming and the amplification of the global hydrological cycle, observed global multidecadal salinity changes typically have focused on the linear response to anthropogenic forcing, but not on salinity variations due to changes in the static stability and or variability due to the intrinsic ocean or internal climate processes. Here, we examine the static stability and spatiotemporal variability of upper ocean salinity across a hierarchy of models and reanalyses. In particular, we partition the variance into time bands via application of singular spectral analysis, considering sea surface salinity (SSS), the Brunt Vaisala frequency (N2), and ocean salinity stratification (OSS) in terms of the stabilizing effect due to the haline part of N2 over the upper 500m.
Presented at the 2012 AGU Fall Meeting
Schmitt, R.W. (03-Dec-12). A multi-national study of the surface salinity maximum of the North Atlantic was initiated in 2012. We are seeking answers to basic questions about how the salinity maximum is maintained.
Bingham, F., Li, Z., Tsontos, V., and Li, P. (12-Mar-18). This presentation summarizes SPURS-2 Information System datasets and provides instructions for posting on the SPURS-2 website. Options are included for data archival (PO.DAAC, NODC, Geoscience Data Journal) in association with metadata, publications, presentations, and other applicable documentation.
Bingham, F. and Li, Z. (24-May-17). A short presentation on the data management efforts associated with SPURS-2.
Drushka, K., Asher, B., Thompson, E., Jessup, A. and Iyer, S. (12-Mar-18). In this presentation, the authors present current research into the impacts of small-scale forcing (rain, wind, wave) on the structure and evolution of the upper 5m of the ocean.
Schanze, J.J., Springer, S.R., Lagerloef, G.S.E., and Thompson, E.J. (12-Mar-18). In this presentation, the Salinity Snake is described along with early SPUR-2 results and a simple model.
Hodges, B. (12-Mar-18). The author describes sampling and performance of three wave gliders and presents statistics of the properties of freshwater puddles.
Yang, J. and Riser, S.C. (12-Mar-18). The authors compare rain amounts/rates and wind speed measurements collected from a central mooring and a Passive Aquatic Listener (PAL) on Argo floats.
Font, J., Ward, B., Emelianov, M., Busecke, J., and Morsest, S. (26-Feb-14). SPURS-MIDAS on board the Spanish R/V Sarmiento de Gamboa was a contribution to SPURS (Salinity Processes in the Upper ocean Regional Study) focused on the processes responsible for the formation and maintenance of the salinity maximum associated to the North Atlantic subtropical gyre.
Bingham, F., D'Addezio, J., and Ulfsax, K. (30-Apr-19). A high-resolution global model (i.e., MITgcm) is used to quantify the sub-footprint variability (SFV) embedded in satellite-based estimates of sea surface salinity. SFV is computed on a 2x2 degree evaluation grid using weighted standard deviation. Analysis of seven latitudes/longitudes, including a location in the SPURS-2 region, show that SFV is large in western boundary currents, frontal regions, river outflows, etc.
Bingham, F. (09-Nov-18). How large is the variability of sea surface salinity (SSS) within the footprint of a satellite like Aquarius or SMAP? How do we quantify differences between in situ and remotely sensed estimates of SSS due to variability within the satellite footprint? What are the space/time scales of SSS variability? In this presentation the author addresses these questions using data obtained from the SPURS-1 and 2 field campaigns.
Bingham, F. (28-Aug-18). Using the SPURS-1 and SPURS-2 datasets, I calculated the subfootprint variability (SFV) of sea surface salinity (SSS). The SFV was defined as the weighted standard deviation of SSS within a 50 km distance of the central mooring for each field campaign. Data for SPURS-1 included drifters, shipboard TSGs, wavegliders, etc. For SPURS-2 the calculation was only done using waveglider data. Separate calculations were done for each field campaign using weekly mooring records, plus a high resolution ROMS model run.
Meissner, T. and Wentz, F. (31-Oct-12). Presented at the 2012 Aquarius Calibration/Validation Workshop at Goddard Space Flight Center.
Dinnat, E. and Le Vine, D. (18-Jan-17). The objective of this analysis is to use observed Aquarius antenna temperatures (Ta obs) and simulations (sims) to apply empirical linear adjustments to brightness temperature (Tb) data. These adjustments would be checked against instrumented land-based reference sites that were covered by Aquarius beams: Little River was covered by beam 2; and Little Washita was covered by beam 3. Graphs of measured versus modeled Ta (vertical polarization) for ocean data and ~30 Aquarius cold sky (CS) calibrations have been used to calculate slope and offset values. The adjusted calibration was checked using bias and scattering of land data.
Le Vine, D., Dinnat, E., Meissner, T., Wentz, F., and Lagerloef, G. (11-Apr-16). Aquarius is a radiometer/scatterometer combination specifically designed for remote sensing of sea surface salinity. The instrument was lost on June 7, 2015 when a power failure on the satellite resulted in loss of control of the observatory. This paper will report the plans for the mission and data processing and the status of the validation of the SSS data against Argo measurements.
Le Vine, D., Dinnat, E., Lagerloef, G., de Matthaeis, P., Kao, H.Y., Meissner, T., and Wentz, F. (26-Nov-14). This paper will give the status of the Aquarius instrument and salinity retrieval, mention some new applications of the data and summarize the current research issues being addressed to improve the retrieved salinity. Aquarius was launched on June 10, 2011 to monitor the global salinity field in the open ocean. This radiometer/scatterometer (i.e. passive/active) instrument is part of the Aquarius/SAC-D observatory. The instrument has been operating continuously since being turned on in August and the initial map of sea surface salinity was released one month later (September, 2011). The quality of the salinity retrieval has improved continuously since then and is approaching the goal of 0.2 psu accuracy (RMS globally each month).
de Matthaeis, P. (30-Jan-13). Overview of the following: long and short accumulations of radio frequency interference (RFI); RFI detection algorithm; issues with RFI (e.g., removal of "short accumulation 1" values, which are inconsistent with short accumulations 2 to 5); detection algorithm thresholds; and equalization of false alarm rate.
de Matthaeis, P., Soldo, Y., and Le Vine, D. (18-Jan-17). An overview of completed updates to the Aquarius Radio Frequency Interference (RFI) algorithm is provided along with potential new improvements (e.g., additional RFI flags based on higher-order statistics and turning of parameters to reduce missed detection and/or false alarm rate). Undetected low-level RFI is an unresolved issue and its effect on salinity retrievals is not yet quantified. An statistical analysis of measurements in low-RFI and RFI-free regions has been conducted, including a case study in the North Atlantic Ocean whose RFI environment changed dramatically after adjustment of radar frequencies in Northern Canadian (Oct 2013). Preliminary results indicate that the Aquarius RFI filter may miss low-level RFI but further studies are needed.
Meissner, T., Wentz, F., Manaster, A., and Lindsley, R. (19-Sep-17). A comparison of SMAP and Aquarius salinity data, including an overview of the SMAP instrument and retrieval algorithm.
Meissner, T., Wentz., F., and Manaster, A. (29-Apr-19). Latest Remote Sensing Systems (RSS) processing of SMAP salinity data release (Version 3) is outlined along with a preview of Version 4. Details of V3 are provided including rain impact, comparisons with SMAP Version 2, Argo, and Aquarius Version 5 data.
Hormann, V., Centurioni, L., Maximenko, N., and Chao, Y. (12-Mar-18). The authors look at how drifters provide an expanding context to observations at the central mooring site.
Hormann, V., Centurioni, L., Maximenko, N., and Chao, Y. (30-Apr-19). Langragian drifters are used to investigate the effect of large-scale circulation on the development, location, and variability of the salinity minimum in the SPURS-2 region. Drifters show variability in near-surface salinity and temperature with saltier and colder water towards the middle of the Pacific. SMAP sea surface salinity data show an overall positive (i.e., fresh) bias when compared with drifter data in the SPURS-2 region.
Lagerloef, G., Kao, H-Y., and Carey, D. (30-Mar-16). A major science objective is to build a long term satellite salinity climate data record (CDR) to measure climatic trends in ocean salinity and marine water cycle. This requires decadal measurement records and long-term calibration stability, stretching the present data to its limits. This presentation focuses on which trends may be observable with our present satellite record. Empirical orthogonal function (EOF) decomposition was used to analyze variance of Aquarius monthly salinity data (V4.0, V4.1), Argo data, and HYCOM model salinity. The outcome of this analysis a recommendation to: discontinue using HYCOM as a calibration target; use Argo in areas where its EOFs 1 and 2 have minimum variance; and use individual Argo matchups for channel calibrations (Aquarius Level 2 swath data).
Weissman, D.E., Morey, S., and Bourassa, M. (23-July-17). This project is focused on improving methods of estimating salinity from SMAP data that will be applied to yield new information on salinity variability in regions impacted by river plumes.
Zhang, S. and Du, L. (26-Feb-14). Pacific salinity variations in the North Hemisphere Ocean are examined by using Ishii v6.9 datasets from 1980 through 2010.
Lorenzo, B., Cuello, A., Raed, M., Sedeño, A., Sánchez, Y., Antes, M., Gari, J., and Miño, R (17-Nov-15). Palabras Clave: Concentración, Hielo marino, Radiómetro de Microonda Antarctica is one of the most inhospitable and inaccessible places on Earth, located to the South of 60° S. There, it is 90% of the ice of the planet and almost three quarters of the reserves of fresh water of the world.
Yu, L. (28-Aug-18). The subtropical surface salinity maximum (SSS-max), the net evaporation maximum, and the subtropical underwater (STUW) are intertwined with each other and with the wind-driven gyre circulation of the upper ocean. The evaporation-minus-precipitation (E-P) flux is a forcing for SSS-max, and the SSS-max is the source water in the subduction process that forms the STUW. Since neither the E-P flux nor the subduction process can be observed directly, satellite observations of the SSS-max provide not only a useful additional gauge on the change of ocean water cycle but also a window into the water mass exchange between the ocean surface and the permanent pycnocline.
Yueh, S., Brown, S., Meissner, T., Freedman, A., Piepmeier, J., LeVine, D., Dinnat, E., Wentz, F., and Lagerloef, G. (29-Jan-13). Report includes: new model patterns were generated using a higher fidelity model developed for SMAP (Soil Moisture Active Passive); new APC terms and correction maps generated from the 2012 model patterns; recommendation that the Aquarius project use the new patterns; and potential issue that new patterns have a higher spill-over fraction compared to previous patterns.
Soldo, Y., Le Vine, D., Dinnat, E., Gales, J., and Hong, L. (18-Jan-17). Changes to the Aquarius land model fall into three general categories: (1) Discontinuities (e.g., Faraday angle, soil moisture near coasts, frozen soils, ice); (2) Consistency with SMAP (e.g., land cover classification, dielectric mixing, vegetation opacity, single-scattering albedo, roughness parameters, soil attributes, and ancillary data); and (3) Bug fixes. Data are presented for measured versus expected antenna temperature (Ta), comparing the old and new land models. The goal for planned land corrections is to use the measured brightness temperature (TB) in conjunction with a forward land model.
Vazquez-Cuervo, J. and Tsontos, V. (29-Aug-18). This talk presents a summary of the archival process for Aquarius and the support and distribution of NASA Salinity data going forward. Aquarius V 5.0 end-of-mission data was archived and released publicly in December 2017. The Phase F Aquarius mission artifact preservation and closeout task were completed in July 2018.
Reverdin, G., Centurioni, L., Sena-Martins, M., Garcia-Ladona, E., Ballabrera, J., Savador, J., Sommer, A., and Boutin, J. (25-Apr-17). Surface drifters have been introduced in the early 1990s by P.P. Niiler to measure the salinity of the near-surface water as well as its temperature. First, they were deployed to document large scale advection of surface salinity fronts, such as during TOGA-COARE (1991). More recently, salinity drifter data were used for three purposes: 1 - provide in situ data coverage for validation of sea surface (SSS) products, such as provided by band-L microwave radiometry from satellite missions, Aquarius, SMOS, SMAP 2 - provide data for better understanding upper ocean response to air-sea interactions, such as during rainfall, or near-surface warming during low wind events 3 - provide estimates of surface advection of salinity features and their contribution to ocean freshwater budget We will review the drifters that have been deployed and where data were collected, the challenges encountered in correcting the data, ongoing plans and future developments.
Vinogradova, N., Buckley, M., Piecuch, C., and Ponte, R. (22-May-17). In recent decades, noticeable decadal salinity trends have emerged at the ocean surface, reflecting the changes in the ocean water cycle, strength of the ocean circulation, and changes in the ocean transports of salt. A number of potential causes for the observed changes have been suggested, including those related to anthropogenic aerosol forcing as well as natural climate fluctuations. Here we explore how the recent decadal salinity trends fit into the long-term picture, focusing on those ocean regions where the decadal changes oppose the long-term trends.
Soloviev, A., Matt, S., and Fujimura, A. (28-Nov-14). Surface freshwater plumes contributing to the formation of the barrier layer and salinity fronts Some areas of the World Ocean are characterized by substantial influx of freshwater. Localized rain and river runoff may produce relatively shallow, near-surface freshwater plumes. Due to buoyancy forces, these plumes have a tendency to spread in the horizontal direction. These buoyancy-driven flows are a type of the organized structure resembling a classical gravity current. Buoyancy-driven surface currents are an important component of the oceanic environment, leading to water mass exchange by horizontal advection and enhanced vertical mixing. The freshwater plumes can be linked to larger scale features such as the barrier layer and fronts, contributing to the salinity field in the Aquarius and SMOS footprints.
Farrar, T., Rainville, L., Plueddemann, A., Kessler, B., Lee, C., Hodges, B., Schmitt, R., Riser, S., Edson, J., Eriksen, C., and Fratantoni, D. (24-May-17). The Salinity Processes Upper-ocean Regional Study (SPURS) was a field campaign focused on understanding the physical processes affecting the evolution of upper-ocean salinity in the region of climatological maximum sea surface salinity (SSS) in the subtropical North Atlantic. An upper-ocean salinity budget provides a useful framework for guiding progress toward that goal.
Chi, N. and Lien, R. (24-Feb-16). The oceanic surface mixed layer salinity budget is evaluated during Madden-Julian Oscillation (MJO) events in the central equatorial Indian Ocean. As part of the DYNAMO field campaign (September 2011 - January 2012), three MJO events were recorded at two mooring sites (0S 79E and 1.5S 79E).
Richards, K., Melnichenko, O., and Jia, Y. (07-Nov-18). The Madden-Julian oscillation is the largest element of the intraseasonal (30- to 90-day) variability in the tropical atmosphere. Freshwater plays an important role in stratifying the upper ocean in the Indo-Pacific warm pool and along the thermocline ridge. Salinity and sea surface temperature measurements can provide insight into the formation of fresh and warm layers in these cycles, helping to determine their relative importance for atmospheric interactions in the region.
Grodsky, S.A., Carton, J.A., and Bryan, F.O. (26-Feb-14). Sea surface salinity (SSS) measurements from the Aquarius/SACD satellite reveal the seasonal development of a local salinity maximum in the northwestern tropical Atlantic in boreal winter to early spring.
Morrow, R. and Kestenare, E. (09-Nov-18). Continuous sea surface temperature (SST) and sea surface salinity (SSS) measurements have been collected onboard a supply ship between Tasmania and Dumont D'Urville, Antarctica as part of the SURVOSTRAL program (Surveillance de l'Océan Austral) since 1992. The ship makes 6-10 repeat sections per year during the warming, melting cycle (October to March) in the Sea Ice Zone south of 60°S near 140°E. In this presentation, the authors describe observed changes in SST and SSS since 1992, the presence of three distinct phases of interannual SSS and sea-ice variations, and the implications of the 2010 Mertz Glacier Tongue calving.
Boutin, J. (15-Apr-13). A presentation by the Surface Stratification Working Group at the 2013 SMOS & Aquarius Science Workshop in Brest, France.
Vinogradova, N., Ponte, R., Fukumori, I., and Wang, O. (25-May-17). The modern salinity observing system includes an expansive network of in situ and space-borne measurements. Reconciling salinity estimates from these different platforms into a coherent picture is one of the objectives of the NASA Ocean Salinity Science Team and the Satellite & In Situ Salinity (SISS) working group. Here we introduce a new salinity estimate based on the synthesis of information from various sources over the 1992-2015 period.
Umbert, M., Portabella, M., Guimbard, S., Ballabrea, J., and Turiel, A. (26-Nov-14). Remote sensing imagery of the ocean surface provides a synoptic view of mesoscale signatures from different ocean scalars advected by the oceanic flow. The most probable origin of the observed structures is the turbulent character of the oceanic flow as they slowly evolve and are very persistent over time scales compatible with ocean mesoscale dynamics. At spatial scales of kilometers, turbulence is mainly 2D, and a complex geometry, full of filaments and eddies of different sizes, emerges in remote sensing images of surface chlorophyll-a concentration (Chl-a) and sea surface salinity (SSS), as well as in the better resolved sea surface temperature (SST) and sea surface height (SSH).
Colliander, A., Dinnat, E., Le Vine, D., and Kainulainen, J. (28-Sep-15). The antenna pattern and observation geometry of the SMOS zero-baseline radiometer, which is used as a reference for the SMOS brightness temperature calibration, was applied to Aquarius simulator, which is used as a reference for the Aquarius brightness temperature calibration. In the preliminary analysis, simulations carried out over a three month period show remarkable agreement between the measurements and simulations.
Ruff, C., Mims, A. and Chen, D. (15-Nov-11). A trend analysis and overview of the antenna temperature (Ta) calibration. Two calibration approaches were used: a global average, and a vicarious cold calibration. This was performed for the full time series available - from August to November 2011.
Ruf, C., Mims, A., and Chen, D. (16-Nov-11). A trend analysis and overview of the antenna temperature (Ta) calibration. Two calibration approaches were used: a global average, and a vicarious cold calibration. This was performed for the full time series available - from August to November 2011.
Busecke, J., Gordon, A., and Abernathey, R. (24-May-17). Lateral mixing by mesoscale eddies is widely recognized as a crucial mechanism for the global ocean circulation and the associated heat/salt/tracer transports. The Salinity in the Upper Ocean Processes Study (SPURS) confirmed the importance of eddy mixing for the surface salinity fields even in the center of the subtropical gyre of the North Atlantic. We focus on the global salinity maxima due to their role as indicators of global changes in the hydrological cycle as well as providing the source water masses for the shallow overturning circulation.
Schanze, J. (31-Mar-15). The Thermodynamic Equation of State 2010 (TEOS-10) has been adopted by major research organizations, and should be used for all publications. In addition, measurements of density and spice are useful derived quantities. The question discussed is whether it makes sense to integrate these quantities into the Aquarius product, and if so, at what level?
Presented at the 2012 AGU Fall Meeting
Meissner, T., Wentz, F.J., Hilburn, K A., Lagerloef, G.S.E., and Le Vine, D.M. (03-Dec-12). The Aquarius L-band radiometer/scatterometer system is designed to provide monthly salinity maps at 150 km spatial scale to an accuracy of 0.2 psu. The sensor was launched on June 10, 2011, aboard the Argentine CONAE SAC-D spacecraft. The L-band radiometers and the scatterometer have been taking science data observations since August 25, 2011. This presentation discusses the current state of the Aquarius Level processing algorithm, which transforms radiometer counts ultimately into sea surface salinity.
de Matthaeis, P., Kim, S., Soldo, Y., and Le Vine, D. (14-Nov-14). In this work, some observed changes in regional RFI environments are analyzed with the goal of better understanding the performance of the Aquarius RFI algorithm, in particular situations such as when low-level or non-impulsive interference is present. The effect and implications on the salinity retrieval are presented and discussed.
Wentz, F.J. and Meissner, T. (11-Apr-12). Overview of the Aquarius salinity retrieval algorithm concludes: Aquarius and the salinity retrieval algorithm are working well; standard deviation of retrieval salinity versus HYCOM (computer model) is 0.6 psu; standard deviation for monthly averages is 0.4 psu; and there are issues that need to be resolved to achieve the goal of 0.2 psu (e.g., small radiometer pointing errors, radiometer calibration time drifts, revised antenna pattern correction, etc.).
Meissner, T., Wentz, F., Hilburn, K., Lagerloef, G., and Le Vine, D. (28-Sep-15). This paper gives an overview of the algorithm for retrieving sea surface salinity from the AQUARIUS L-band radiometer and its physical background.
Meissner, T., Wentz, F., Lagerloef, G., and Le Vine, D. (28-Sep-15). This paper gives an overview of the algorithm for retrieving sea surface salinity from the AQUARIUS L-band radiometer and its physical background.
Wentz, F., Meissner, T., Scott, J., and Hilburn, K. (13-Nov-14). This presentation gives an overview of updates and improvements that we plan to make in the Aquarius salinity retrieval algorithm for the next major release.
Meissner, T., Wentz, F., Ricciardulli, L., Hilburn, K., and Scott, J. (10-Sep-15). This paper summarizes the major steps of the updates in the Aquarius Level 2 ocean surface salinity (SSS) retrieval from Version 2.0 to Version 3.0, which is scheduled to be released in May 2014.
Meissner, T., Wentz, F., and Hilburn, K. (26-Feb-14). The Aquarius L-band radiometer/scatterometer system is designed to provide ocean surface salinity at an accuracy of 0.2 psu. This poses a challenge for the instrument design and calibration as much as for the salinity retrieval algorithm. Many sizeable spurious signals have to be removed. In this presentation, the authors discuss the most important ones and the methods for their mitigation.
Kao, H-Y. and Lagerloef, G. (16-Apr-13). The Aquarius instrument is designed to use three horns to measure the sea surface salinity (SSS) at the same time. Taking the advantages of this particular design, here we compare the SSS in three beams and attempt to identify the signal and noise within.
Lang, R., Zhou, Y., Dinnat, E., and Le Vine, D.M. (23-July-17). Existing model functions for the dielectric constant of sea water produce viable retrievals of ocean salinity but with differences that are important for eventual optimization of the science product. Issues exist in cold water and the dependence on sea surface temperature.
Drushka, K., Gille, S., and Sprintall, J. (12-Nov-14). TAO mooring data are used to estimate the diurnal cycle of salinity in the tropics and to assess the drivers of diurnal salinity. A comparison against the Aquarius ascending and descending salinity observations reveals that the ascending/descending bias version 3.0 of Aquarius is generally an order of magnitude larger than the diurnal cycle in salinity at 1-m depth.
Drushka, K., Gille, S.T., and Sprintall, J. (26-Feb-14). In the present study, salinity observations from Aquarius and Argo profiling floats are combined in order to extract the amplitude and phase of the diurnal salinity cycle throughout the tropics and subtropics.
Kim, S., Lee, J., Hong, C., Pang, I., de Matthaeis, P., and Yueh, S. (13-Nov-13). This paper assesses the quality of the Aquarius salinity product over the East China Sea in the presence of land and RFI (radiofrequency interference) contamination. Two models for simulating the land emission are compared and the results indicate that the monitoring of salinity by the Aquarius instrument in the marginal sea is feasible despite the two contaminants.
Tang, W., Yueh, S., Fore, A., and Hayashi, A. (13-Nov-14). The objective of this study is to develop a rain roughness correction to reduce the uncertainty of Aquarius sea surface salinity (SSS) retrieved under rainy conditions. The calibration reference chosen by the Aquarius project calibration/validation team is the SSS from HYCOM (SSSHYCOM), with Geophysical Model Function built using rain-free data. Under rainy conditions, surface salinity stratification associated with rain freshwater inputs may cause large discrepancy in salinity measured by Aquarius at 1-2 cm (the penetration depth of L-band radiometer) and SSSHYCOM a few meters below the surface.
Clayson, C.A., Edson, J., and Farrar, T. (07-Nov-18). The SPURS-2 cruise aimed to study the fate of freshwater (precipitation) in the Intertropical Convergence Zone. Both in situ and atmospheric observations allowed for an examination of the fluxes between the atmosphere and ocean. This work investigates the relationships between surface forcing of freshwater and heat in creating salinity, temperature and turbulence profiles, and how larger-scale atmospheric conditions may play a role in surface salinity variability.
Presented at the 2014 AGU Fall Meeting
Johannes, J. and Busecke, M. (18-Dec-14). Excess evaporation in the subtropics forms a local surface salinity maximum in all subtropical ocean basins. Descent of these waters to depth creates a core layer marked by a subsurface salinity maximum (S-max) spreading towards the equator, an integral part of the lower limb of the meridional subtropical overturning cell. Here we will investigate what governs the evolution of the S-max core layer in the North Atlantic.
Alory, G., Delcroix, T.C., Téchiné, P., Diverrès, D., Varillon, D., Cravatte, S.E., Gouriou, Y., Grelet, J., Jacquin, S., Kestenare, E., Maes, C., Morrow, R., Perrier, J., Reverdin, G.P., and Roubaud, F. (25-Feb-16). Sea Surface Salinity (SSS) is an essential climate variable that requires long term in situ observation. The French SSS Observation Service (SSS-OS) manages a network of Voluntary Observing Ships equipped with thermosalinographs (TSG).
Akhoudas, C., Sallée, J.B., and Reverdin, G. (09-Nov-18). The freshwater cycle of the Southern Ocean is pivotal for Earth's climate, but is poorly observed and understood. In this study, the authors examine the Southeastern Waddell Sea, a major site for deep water formation. Oxygen and deuterium isotope data, acquired from in situ sampling during the 2017 WAPITI project cruise, have shed new light on ocean-ice interaction, circulation, and the freshwater cycle.
Levang, S. and Schmitt, R.W. (25-Feb-16). The global water cycle is expected to intensify in a warming climate. To identify potential patterns and magnitudes of change, we analyze outputs from a high emissions scenario (RCP8.5) of the Coupled Model Intercomparison Project 5 (CMIP5) for evaporation (E), precipitation (P), atmospheric vapor transport (Q), and sea surface salinity (SSS) over the coming century.
Scott, J. (31-Mar-15). Aquarius uses auxiliary SST measurements in the Aquarius SSS retrieval. This presentation attempts to determine whether there are uncertainties inherent in the use of auxiliary SST, and if those uncertainties lead to systematic errors in the Aquarius SSS retrieval.
Hackert, E., Kovach, R., Ballabrera-Poy, J., Busalacchi, A.J., and Vernieres, G. (19-Sep-17). This talk examines the impact of Sea Surface Salinity (SSS) on coupled ENSO forecasts, using the Indo-Pacific ocean as its sampling area. The assimilation of Aquarius and SMAP SSS data was found to significantly improve coupled forecasts.
Presented at the 2014 AGU Fall Meeting
Solomon, A.I., Polvani, L.M., Abernathey, R.P., and Smith, K.L. (18-Dec-14). Observations have revealed systematic changes in the temperature and salinity of the Southern Ocean since 1960. These trends reflect the evolving exchange of heat and momentum between atmosphere and ocean and are, in part, driven by anthropogenic emissions.
Iyer, S. and Drushka, K. (12-Feb-18). Freshwater transport, fluxes, and dissipation in the upper ocean are major components of the global hydrologic cycle, which is critically important to study considering the earth's warming climate. It is known that rainfall can form lenses of relatively fresh water at the ocean surface which persist until they are mixed away by turbulent processes. Previous studies have suggested that stratification suppresses turbulence below and enhances turbulence within fresh lenses until lenses are mixed away by wind or nighttime convection. However, the specific relationships between atmospheric parameters (e.g., wind, rain, heat flux) and turbulent dissipation rates at the sea surface have not been widely studied. The objective of this work is to quantify these relationships, determine how the transfer of turbulent energy controls the evolution of fresh lenses, and assess how these processes may impact the large-scale water cycle.
Fore, A., Yueh, S.H., Tang, W., and Hayashi, A. (12-Feb-18). The Soil Moisture Active Passive (SMAP) mission was launched January 31st, 2015. It is designed to measure the soil moisture over land using a combined active / passive L-band system. Due to the Aquarius mission, L-band model functions for ocean winds and salinity are already mature and have been directly applied to the SMAP mission. In contrast to Aquarius, the higher resolution and scanning geometry of SMAP allows for wide-swath ocean winds and salinities to be retrieved. In this talk we present the SMAP Sea Surface Salinity (SSS) dataset and algorithm.
Fore, A., Yueh, S., Tang, W., and Hayashi, A. (27-Aug-18). The Soil Moisture Active Passive (SMAP) mission was launched January 31st, 2015. It is designed to measure the soil moisture over land using a combined active / passive L-band system. Due to the Aquarius mission, L-band model functions for ocean winds and salinity are already mature and have been directly applied to the SMAP mission. In contrast to Aquarius, the higher resolution and scanning geometry of SMAP allows for wide-swath ocean winds and salinities to be retrieved. In this talk we present the SMAP Sea Surface Salinity (SSS) dataset and algorithm.
Fore, A., Yueh, S., Tang, W., and Hayashi, A. (29-Apr-19). Latest JPL processing of SMAP salinity data release (Version 4.2) is outlined. Details are provided on three-stage brightness temperature calibration, gridding, and data availability (including near-real-time).
Matano, R.P., Combes, V., and Strub, P.T. (26-Feb-14). The freshwater discharge from the La Plata River - the fifth largest river of the world - spreads along the coasts of Argentina, Uruguay and Brazil forming a low-salinity plume that is modulated by the effect of local wind forcing, tides and the offshore flows of the Brazil and Malvinas Currents. We use Aquarius sea surface salinity data to document, for the first time, the excursions of the La Plata River plume into the deep ocean.
Lindstrom, E., Lagerloef, G., and Le Vine, D. (17-Nov-15). Aquarius was NASA's first mission dedicated to measuring ocean surface salinity, and demonstrated both technical feasibility and scientific merit. The overarching science goal was to understand the links between ocean circulation, the water cycle and climate.
Maamaatuaiahutapu, K., Witting, J., and Martinez, E.C. (12-Feb-18). Spreading and transport of the Maximum Salinity Core Layer (MSCL), defined as water with salinity higher than 36 psu, is investigated from hydrographic data sets collected along twelve cross-sections by the Sea education Association (SEA) between Tahiti and the equator from 2008 and 2015, the ARGO data objectively mapped from JAMSTEC and satellite remote sensing. Aquarius sea surface salinity data show that the MSCL occupied an area averaged over time of about 6.7 106 km2 with an increase of the occupancy in 2015.
Bingham, F., Busecke, J., Gordon, A., Giulivi, C., and Li, Z. (12-Nov-13). The subtropical surface salinity maximum (SSS-max) in the North Atlantic was studied as part of the SPURS (Salinity Processes in the Upper Ocean Regional Study) experiment in 2012-2013. This paper documents the structure and variability of the SSS-max using Aquarius data during the two-year period August 2011 - August 2013.
Bingham, F., Busecke, J., Gordon, A., Giulivi, C., and Li, Z. (26-Feb-14). The subtropical surface salinity maximum (SSM) in the North Atlantic was studied as part of the SPURS (Salinity Processes in the Upper Ocean Regional Study) experiment in 2012-2013. This poster documents the structure and variability of the SSM using Aquarius data during the two-year period August 2011 - August 2013.
Bingham, F., Busecke, Julius., Giulivi, C., Gordon, A., and Li, Z. (12-Nov-14). Aquarius satellite derived sea surface salinity (SSS) data from August 2011 through September 2013 reveals significant seasonal migration and freshening of the subtropical surface salinity maximum (SSS-max) area in the North Atlantic, in good agreement with in situ observations, including those obtained as part of the SPURS (Salinity Processes in the Upper Ocean Regional Study) field experiment in 2012-2013.
Schanze, J.J., Springer, S.R., Lagerloef, G.S.E., and Thompson, E.J. (07-Nov-18). The Salinity Snake measures salinity at 1-2 cm depth and was deployed during the SPURS-2 campaign in the tropical western Pacific in 2016 and 2017. 20,000 km of measurements were taken over two months using the Salinity Snake, which collected data at a range of wind speeds. There is a very good match-up between the Salinity Snake data and SMAP. Models can be used to simulate the variety of freshwater lenses encountered during SPURS-2, which could be used to classify surface freshening events based on their signature. Overall, the Salinity Snake has collected more than 40,000 km of very-near surface salinity data, averaging .07 g/kg difference between 5 meters and the surface in the Intertropical Convergence Zone.
Schanze, J.J., Springer, S.R., Lagerloef, G.S.E., and Thompson, E.J. (12-Feb-18). An instrument capable of measuring surface salinity and temperature at satellite radiometric depths of 1-2 cm (the 'Salinity Snake') was deployed during two cruises of the Salinity Processes in the Upper Ocean Regional Study 2 (SPURS-2) during August-September 2016 and SPURS-2 and October-November 2017. Additional measurements at 1m, 2m, and 5m from through-hull systems allow the near-surface stratification to be estimated. Approximately 100 freshwater lenses with significant (>0.5 g/kg) salinity differences between the surface and 5m were found, ranging in size from 3 to 50 km. A significant portion (>40%) of these lenses were encountered during calm conditions without any measured precipitation on the ship. This suggests the potential persistence of such freshwater lenses for many hours or even days, and a strong dependence on wind-driven mixing, which acts to destroy very-near surface stratification.
Tang, W., Yueh, S., Yang, D., Fore, A., and Hayashi, A. (27-Aug-18). Sea surface salinity (SSS) links various components of the Arctic freshwater system. SSS responds to freshwater inputs from river discharge, sea ice change, precipitation and evaporation, and oceanic transport through the open straits of the Pacific and Atlantic oceans. However, in situ SSS data in the Arctic Ocean are very sparse and insufficient to depict the large-scale variability. With improved land correction, the JPL SMAP SSS algorithm is able to retrieve SSS in ice-free regions within 35 km of the coast.
Tang, W., Yueh, S., Lagerloef, G., Fore, A., and Hayashi, A. (14-Nov-13). This presentation looks at geophysical model functions with rain correction and CAP retrieval; the seasonal evolution of the equatorial Pacific fresh water pools; and the impact of rain correction on the mixed layer salt storage tendency.
Tang, W., Yueh, S., Lagerloef, G., Fore, A., and Hayashi, A. (26-Feb-14). Rain has instantaneous impact on the sea surface salinity (SSS), but also interfere with the microwave remote sensing signals, making the task to retrieve SSS under rainy condition difficult. A rain correction scheme has been developed based on analysis of the L-band radiometer/scatterometer residual signals after accounting for roughness due to wind and flat surface emissivity.
Presented at the 2014 AGU Fall Meeting
Hasson, A.E.A. and Lee, T. (18-Dec-14). In this study, we use various satellite measurements of sea surface salinity and sea surface temperature to characterize the mean spatial structure and temporal variability of surface density gradients in the tropical Pacific Ocean from 2011 to present.
Presented at the 95th AMS Meeting
Hasson, A. and Lee, T. (07-Jan-15). Horizontal gradients of surface density in the ocean are important to frontal genesis and instability (e.g., Tropical Instability Waves - TIWs) associated with ocean currents. They also have significant implications to air-sea interaction and biogeochemistry. Sea Surface Temperature (SST) and Salinity (SSS) both contribute to the horizontal density gradient. For the first time surface density can be globally inferred from remote sensing with unprecedented spatial and temporal scales.
Hasson, A. and Lee, T. (27-Nov-14). Horizontal gradients of surface density in the ocean are important to frontal genesis and instability associated with ocean currents. They also have significant implications to air-sea interaction and biogeochemistry. Sea Surface Temperature (SST) and Salinity (SSS) both contribute to the horizontal density gradient. For the first time surface density can be globally inferred from remote sensing with unprecedented spatial and temporal scales. Since August 2011, NASA’s Aquarius/SAC-D satellite mission and since January 2010, ESA’s SMOS mission have provided global high resolution SSS datasets. In this study, we use various satellite measurements of SSS and SST to characterize the mean spatial structure and temporal variability of surface density gradients in the tropical Pacific Ocean from 2011 to present.
Presented at the 2014 AGU Fall Meeting
Young, V., Subrahmanyam, B., and Nyadjro, E.S. (18-Dec-14). Satellite-derived salinity from the Aquarius salinity mission (September, 2011-present) and Simple Ocean Data Assimilation (SODA) Reanalysis (1950-2010) are used to estimate freshwater and salt fluxes. Our results indicate that recent changes in freshwater and salt fluxes are a major component of the deep-ocean warming in the Southern Ocean.
Presented at the 2014 AGU Fall Meeting
Tang, W., Yueh, S.H., and Liu, W.T. (18-Dec-14). Indian monsoon is one of the most important of all tropical climate systems. Its onset and spatial/temporal variability have strong economic impact and may cause severe human suffering. Using sea surface salinity (SSS) data from Aquarius/SAC-D satellite mission, we study the seasonal and interannual variability of SSS, to identify the potential sources for the monsoon moisture supply.
Tang, W. and Yueh, S. (25-Apr-17). This study investigates the role of sea surface salinity (SSS) in the water cycle anomaly associated with El Niño Southern Oscillation (ENSO). The 2015-16 El Niño, one of the strongest ENSO events observed in centuries, coincident with unprecedented coverage of spacebased remote sensing of SSS over global oceans. We analyze three SSS data sets: from the NASA's missions of SMAP and Aquarius, and the ESA's Soil Moisture and Ocean Salinity (SMOS). One typical characteristics of an ENSO event is the zonal displacement of the Western equatorial Pacific Fresh Pool (WPFP). The edge of the pool extends eastward during El Niño, retreats westward during La Niña. For super El Niño, the eastern edge of WPFP extends much more east across the equatorial Pacific. Indeed, SSS from SMAP reveals much stronger eastward migration of WPFP starting in April 2015.
Yuan, X., Salama, S., and Su, Z. (24-Feb-16). Sea surface salinity data from both the Aquarius satellite and Argo float in the Indian Ocean are utilized to investigate sea surface salinity's role in South Asian Summer Monsoon.
Presented at the 2014 AGU Fall Meeting
Schanze, J. and Schmitt, R. (18-Dec-14). Large-scale thermal forcing and freshwater fluxes play an essential role in setting the ocean's temperature and salinity. The ratio of the relative contributions of haline and thermal forcing in the mixed layer is maintained by large-scale surface fluxes, leading to important consequences for mixing in the ocean interior.
Schanze, J. and Schmitt, R. (17-Apr-15). Large-scale thermal forcing and freshwater fluxes play an essential role in setting the ocean's temperature and salinity. The ratio of the relative contributions of haline and thermal forcing in the mixed layer is maintained by large-scale surface fluxes, leading to important consequences for mixing in the ocean interior.
Meissner, T., Wentz, F., and Manaster, A. (06-Nov-18). This presentation provides an overview of the RSS SMAP Version 3 (V3) Release, which includes several significant upgrades over previous RSS V2 SMAP SSS products.
Wentz, F., Meissner, T., and Manaster, A. (27-Aug-18). This presentation discusses the resampling and land contamination correction in the RSS SMAP Salinity Version 3 release. We will provide an analysis showing the degradation of the SMAP salinity retrievals as function of distance from the coast with and without applying the land contamination correction, for both the 40-km and the 70-km salinity products.
Meissner, T., Wentz, F., and Manaster, A. (27-Aug-18). This presentation gives a detailed account of the RSS Version 3 SMAP SSS release, which is scheduled for summer 2018. We discuss the major steps of the SMAP salinity retrieval algorithm, including updates and improvements from the Version 2 release and we compare with the algorithm of the Aquarius Version 5 release.
Ruiz-Etcheverry, L.A., Maximenko, N., and Melnicenko, O. (28-Aug-18). The Equatorial Atlantic Ocean is a region dominated by the seasonal trade winds and Inter Tropical Convergence Zone (ITCZ). It is also marked by the existence of a strong sea surface temperature (SST) front due to the formation of the equatorial cold tongue. These features are believed to have strong effects on the atmospheric circulation in the region and thus climate. Little, however, is known about the salinity front that became possible to resolve only with the release of high-resolution satellite salinity products. In this study, we use sea surface salinity (SSS) observations from the Aquarius satellite and from the reanalysis model GLORYS to investigate the spatial structure, temporal variability, and driving mechanisms of the frontal SSS feature in the equatorial Atlantic.
Guerrero R.A., Fenco H., Piola A.R., Matano R., Combes V., Strub T., Chao Y., Saraceno M., Ruiz L., Palma E. (13-Nov-13). The largest variance in sea surface salinity in the subtropical South Atlantic is observed at the western flank of the basin, off the Río de la Plata. The salinity distribution in this area is controlled by the confluence of the Malvinas and the Brazil currents as well as the export of diluted waters from the neighboring shelf. In this presentation, we show that SAC-D/Aquarius data can be used to document the surface expression of the interaction between the shelf and the deep-ocean in this region.
Matano, R., Combes, V., Palma, E., Guerrero, R., Fenco, H., Strub, T., Piola, A.R., Chao, Y., and Saraceno, M. (13-Nov-13). Observations and numerical simulations suggest that subantarctic and subtropical waters on the western South Atlantic continental shelf converge near 33°S. This convergence must be balanced by export of shelf waters to the deep oceans that, together with runoff from Río de la Plata (RdP) and the Patos Lagoon, create extensive regions of low salinity on the Brazil/Malvinas Confluence.
Piola, A.R., Valla, D., Guerrero, R.A., Fenco, H., Möller, O.O., Matano, R.P., Combes, V., Chao, Y., Palma, E.D., Ruiz Etcheverry, L.A., Strub, P.T., and Saraceno, M. (14-Nov-13). The freshwater discharge from the La Plata River generates a sea surface salinity anomaly that characterizes the local outflow of shelf waters into the deep ocean. Here, we discuss the kinematics and dynamics of the observed SSSa using the results of a suite of process-oriented numerical simulations.
Matano, R., Combes, V., Piola, A., Guerrero, R., Palma, E., Strub, T., James, C., Fenco, H., Chao, Y., and Saraceno, M. (13-Nov-14). Sea surface salinity data from Aquarius and SMOS and the results of high-resolution numerical model are used to investigate the shelf-deep ocean exchanges in the southwestern Atlantic region, a region characterized by the freshwater discharge from the La Plata River. The satellite data shows strong seasonal variations of the location where the low salinity shelf waters are exported to the deep ocean: to the south of the La Plata River mouth during the summer and to the north during the winter.
Guerrero, R., Piola, A., Fenco, H., Matano, R., Combes, V., Chao, Y., James, C., Palma, E., Saraceno, M., and Strub, T. (13-Nov-14). We use sea surface salinity (SSS) data from Aquarius and SMOS to describe the shelf-open ocean exchanges in the western South Atlantic near 35°S. The satellite data show a well-defined seasonal pattern. During spring and summer low SSS shelf waters expand offshore and are transferred to the open ocean primarily southeast of the river mouth (from 36 °S to 37°30'S). During fall and winter low SSS waters extend along a coastal plume and the export path to the open ocean distributes along the offshore edge of the plume.
Presented at the 2014 AGU Fall Meeting
Yueh, S., Tang, W., Fore, A., Hayashi, A., Bindlish, R., Lee, T., and Jackson, T.J. (18-Dec-14). Aquarius is a combined passive/active L-band microwave instrument. Its data have been used to retrieve the sea surface salinity using the Combined Active and Passive algorithm with an accuracy of about 0.1 to 0.2 psu Root-Mean-Square between 40 degrees N and 40 degrees S. In addition to the salinity product, Aquarius radiometer data have been used to produce the surface soil moisture globally. We find that the change of soil moisture over the India subcontinent clearly correlates with the timing of India Monsoon, which produces significant precipitation between June and September, and is consistent with the total land mass change derived from the GRACE mission data.
Giulivi, C.F. and Gordon, A.L. (19-Nov-15). Using a diverse set of observational and model data we examine the seasonal to decadal variability of the South Atlantic subtropical gyre in the context of changes in the gyre's relationship to the larger scale ocean and climate system and the response of the gyre interior to its boundary.
Gordon, A.L. (22-May-17). The salty subtropical regimes of the world ocean display significant differences. Evaporation alone is not sufficient to explain the spatial and temporal characteristics of the salty subtropical regimes, the wind also shapes sea surface salinity maximum (SSS-max), both at seasonal and inter annual time scales. However, even the combination of regional air-sea water flux and the wind stress is insufficient to fully explain the SSS-max patterns.
Davis, X.J. and Farrar, J.T. (24-Feb-16). This study examines the subtropical salinity maximum water, or Subtropical Underwater (STUW), in the subtropical regions of the North and South Atlantic, North and South Pacific and Indian Oceans. These salty water masses are important components of the upper-ocean overturning and global water cycle.
Ruiz-Etcheverry, L., Maximenko, N.A., and Melnichenko, O. (12-Feb-18). The Equatorial Atlantic Ocean is a region dominated by the seasonal trade winds and Inter Tropical Convergence Zone (ITCZ). It is also marked by the existence of a strong sea surface temperature (SST) front due to the formation of the equatorial cold tongue. These features are believed to have strong effects on the atmospheric circulation in the region and thus climate. Little, however, is known about the salinity front, whose study became possible only with the release of high-resolution salinity products. In this study, we use three years of sea surface salinity (SSS) observations from Aquarius satellite to investigate the spatial structure, temporal variability, and driving dynamics of the frontal SSS feature in the equatorial Atlantic, its evolution between seasons and differences between individual years.
Ruiz-Etcheverry, L., Maximenko, N., and Melnichenko, O. (20-Sep-17). This poster includes three years of SSS observations from Aquarius to investigate the spatial structure, temporal variability, and driving dynamics of the frontal SSS feature in the equatorial Atlantic.
Schmitt, R. (08-Nov-18). Watersheds produce flooding when extra water is added to the system, and that precipitation must come from a source outside of the watershed itself. Because a majority of evaporation occurs over the ocean, it follows that the extra moisture originates there. Since the flood waters freshen the ocean, the conservation of salt tells us that there must have been high salinity anomalies that preceded the heavy rains. This talk discusses the success of using salinity variability to predict rainfall on land. The use of Neural Networks, trained on historical sea surface salinity and temperature data, were used to create predictions of rainfall in the U.S. Southwest.
Presented at the 2018 AGU Fall Meeting
Schmitt, R.W. (12-Dec-18). Most water on Earth is in the ocean and it is the ultimate source of terrestrial rain. The latent heat flux due to evaporation also dominates the transfer of energy from ocean to the atmosphere and land. While about 50% of surface evaporation from the ocean falls back as local precipitation, the rest is exported from the evaporation-dominated subtropical high pressure systems. This generates high sea surface salinity (SSS) in the subtropical gyres and low SSS in the high and low latitude oceans and coastal regions that receive runoff. About one third of the water exported from the subtropical oceans rains out on land. Anomalously large water export leads to higher SSS, guaranteeing that some part of the climate system will experience more rain; lower SSS indicates less export and less rain elsewhere. We have found that seasonal anomalies in SSS in particular areas of the ocean have remarkable skill for predicting future rainfall in certain regions on land.
Presented at the 2014 AGU Fall Meeting
Volkov, D., Dong, S., and Goni, G.J. (18-Dec-14). As part of the validation of the Aquarius data and a demonstration of its capabilities and utility for oceanographic studies, we use along-track Aquarius data for the determination of the Antarctic Circumpolar Current sea surface salinity fronts between Africa and Antarctica.
Yueh, S., Tang, W., Fore, A., Hayashi, A., Misra, S., and Peng, J. (09-Nov-18). The SMAP mesh antenna contributes some emissivity to the retrieval of sea surface salinity (SSS) data. Just how much emissivity is important to quantify, as a small difference in emissivity can contribute to a large variance in salinity. A reanalysis of Version 3 and Version 4 data using the JPL Geophysical Model Function revealed a small change in the reflector loss compared to pre-launch measurements and model. This change is reflected in the JPL SMAP Version 4.2 SSS product.
Presented at the 2012 AGU Fall Meeting
Banks, C.J., Gommenginger, C.P., Srokosz, M.A., and Snaith, H.M. (03-Dec-12). In November 2009, the European Space Agency (ESA) launched the Soil Moisture and Ocean Salinity (SMOS) satellite and a new era of satellite oceanography began vastly improving our ability to synoptically measure sea surface salinity (SSS). SMOS was joined in June 2011 by the NASA/Argentine Aquarius/SAC-D mission designed specifically to measure SSS.
Asher, W., Drushka, K., Jessup, A.T., and Clark, D. (25-Feb-16). Satellite-mounted microwave radiometers measure sea surface salinity (SSS) as an area-averaged quantity in the top centimeter of the ocean over the footprint of the instrument. If the horizontal variability in SSS is large inside this footprint, sub-grid-scale variability in SSS can affect comparison of the satellite-retrieved SSS with in situ measurements. Understanding the magnitude of horizontal variability in SSS over spatial scales that are relevant to the satellite measurements is therefore important.
Asher, W., Drushka, K., Jessup, A., and Clark, D. (07-Nov-18). There are now a variety of in situ and remote instruments used to measure salinity. However, these instruments measure different depth ranges, from the satellites measuring the top skin of the ocean surface to moorings and autonomous vehicles that can sample over a range of depths. To connect what is occurring at the surface to depth, it is crucial to understand the variability and vertical gradients affecting these measurements. Both a vertical gradient and horizontal variability are observable in salinity and temperature measurements. These gradients are wind-speed dependent, so the effect is also dependent on latitude.
Melnichenko, O., Amores, A., Hacker, P., Maximenko, N., and Potemra, J. (25-May-17). Satellite observations and Argo profile data are used to investigate the vertical structure of meridional eddy freshwater transport in the interiors of the subtropical gyres. To overcome limitations arising from the relative sparseness of in-situ profile data, an eddy composite analysis is utilized; namely, the mean vertical structure of mesoscale eddies and their transport properties are evaluated by synthesizing all available data in the framework of the eddy tracking technique.
Masuelli, S., Heredia, S., and Madero, F. (12-Nov-13). In this work we present the basis to produce weekly and monthly products (L3) of the MWR's geophysical variables, based on the global product definitions for similar purposes.
Shkvorets, I. (26-Feb-14). Internationally adopted as standard method of salinometry, the Autosal technique has been utilized for more than 30 years. However, limitations of the Autosal temperature setting at room temperature creates a discrepancy between the conductivity of the seawater measured by a CTD and by the Autosal. In this paper the author proposes a complementary method for onboard salinity. measurements.
Presented at the 2014 AGU Fall Meeting
Meissner, T., Wentz, F., Le Vine, D., and Lagerloef, G. (18-Dec-14). This presentation reports the status of the Aquarius salinity retrieval algorithm highlighting the advances that have been made for and since the Version 3 release.
Presented at the 95th AMS Meeting
Meissner, T., Wentz, F.J., Smith, D.K., Le Vine, D., and Lagerloef, G. (07-Jan-15). Aquarius is an L-band radiometer/scatterometer (i.e. active/passive) system designed to provide monthly salinity maps at 150 km spatial scale to an accuracy of 0.2 psu. The sensor was launched on June 10, 2011 as part of the Aquarius/SAC-D mission and has been collecting data since August 25, 2011. Version 3 of the data product was released in June 2014 and provides a major milestone towards reaching the mission requirement of 0.2 psu.
Presented at the 2016 AGU Fall Meeting
Busecke, J.J.M., Abernathey, R., and Gordon, A. L. (16-Dec-16). Lateral mixing by mesoscale eddies is widely recognized as a crucial mechanism for the global ocean circulation and the associated heat/salt/tracer transports. The Salinity in the Upper Ocean Processes Study (SPURS) confirmed the importance of eddy mixing for the surface salinity fields even in the center of the subtropical gyre of the North Atlantic. We focus on the global salinity maxima due to their role as indicators for global changes in the hydrological cycle as well as providing the source water masses for the shallow overturning circulation.
Levang, S. and Schmitt, R.W. (12-Feb-18). Global patterns of salinity are an imprint of the atmospheric water cycle, which tends to intensify as the climate warms, making fresh regions fresher and salty regions saltier. However, transport and stirring of salt in the ocean complicate the details of this response. Here we use the Simple Ocean Data Assimilation (SODA) v3.4.1 to investigate timescales of exchange between evaporative and precipitative regimes of the world oceans.
Lee, T. (11-Nov-14). This presentation will present results of the analysis of uncertainty of Aquarius sea surface salinity data on scales of 1000 km with a focus on year-to-year changes currently resolved by Aquarius in order to shed light on the extent to which Aquarius can detect climate variability and change signals like these.
Presented at the 2014 AGU Fall Meeting
Lee, T. (18-Dec-14). Tropical instability waves (TIWs) are important to ocean dynamics, air-sea interaction, and biogeochemistry. Measurements of sea surface salinity (SSS) from the Aquarius/SAC-D and SMOS missions have demonstrated their capabilities to detect TIWs both in the Pacific and the Atlantic Oceans. The accuracy of satellite SSS in representing TIW amplitudes has strong implication to the assimilation of these data in ocean models.
Tsontos,V., Vazquez, J., and Thompson, C. (12-Nov-13). The Physical Oceanography Distributed Active Center (PO.DAAC) serves as the designated NASA repository and distribution node for all Aquarius/SAC-D data products in close collaboration with the project. Here we report on the status of Aquarius data holdings at PO.DAAC, observed patterns of usage of these data sets, and the range of data services and access tools that we provide in support of this mission.
Tsontos, V. and Vazquez, J. (11-Nov-14). The Physical Oceanography Distributed Active Center (PO.DAAC) serves as the official NASA repository and distribution node for all Aquarius/SAC-D data products in close collaboration with the project. Here we report on the status of Aquarius data holdings at PO.DAAC, the range of data services and access tools that we provide in support of this mission, and new efforts underway to support in-situ salinity datasets from the SPURS field campaign.
Vazquez, J. and Tsontos, V. (18-Nov-15). A view of the current state of the availability of Aquarius mission data, including the currently publicly-available dataset Version 4.0., datasets utilized for calibration and validation efforts, and additional datasets from other campaigns (e.g., SPURS field campaign data) available on PO.DAAC.
Tsontos, V. and Vazquez, J. (25-Feb-16). The Physical Oceanography Distributed Active Center (PO.DAAC) serves as the official NASA repository and distribution node for all Aquarius/SAC-D data products in close collaboration with the project. Here we report on the status of NASA salinity data holdings at PO.DAAC, the range of data services and access tools that we provide in support of the Aquarius mission and SPURS in-situ salinity datasets.
Tsontos, V., Vazquez, J., and Lee, T. (23-May-17). The Physical Oceanography Distributed Active Center (PO.DAAC) serves as the designated NASA repository and distribution node for all Aquarius/SAC-D and SMAP sea surface salinity (SSS) mission data products in close collaboration with the projects. Here we report on the status of these data holdings at PO.DAAC, and the range of data services and access tools that we provide in support of NASA salinity.
Utku, C. and Le Vine, D.M. (28-Sep-15). The effect of topography on remote sensing at L-band is examined using the co-located Aquarius radiometer and scatterometer observations over land. A correlation with slope standard deviation is demonstrated for both the radiometer and scatterometer at topographic scales.
Zhang, Y., Bayler, E., and Baker-Yeboah, S. (25-Feb-16). In this study, we compare the NCEI satellite binned Level-3 products to the JPL PODAAC official Aquarius and SMOS Barcelona Expert Center Level-3 SSS products. Also, we present a comparison of the NCEI Level-3 SSS product with the NOAA/NCEI World Ocean Atlas in situ gridded data. Results indicate consistency and a good match of NCEI-binned Level-3 SSS data with other datasets for open ocean areas, with some bias apparent in coastal and high-latitude regions.
Presented at the 2016 AGU Fall Meeting
Zhang, Y., Bayler, E.J., and Baker-Yeboah, S. (16-Dec-16). The NOAA National Centers for Environmental Information (NCEI), as the US archive for oceanographic data, provides long-term data stewardship of in situ sea-surface salinity (SSS) data, including near-real-time and delayed-mode products. These high quality in situ observations enable monitoring and validating Level-2 satellite data from the European Space Agency’s (ESA) Soil Moisture – Ocean Salinity (SMOS), the National Aeronautics and Space Agency’s (NASA) Aquarius mission, and NASA’s Soil Moisture Active-Passive (SMAP) mission.
Brown, S. and Misra, S. (29-Mar-16). This study looked into the possibility of using differences in vertical and horizontal polarization data from the Amazon rainforest, the ocean, and Antarctica as Aquarius calibration model sources. Possible relationships between instrument temperature seasonal variations (e.g., noise diodes, feedhorns, reflector, Dicke load) and regional biases were also investigated. Third Stokes errors were analyzed for regional patterns (e.g., impacts on Q for descending minus ascending orbits). We found an apparent small (about 0.1K) temporal variation present in third Stokes brightness temperatures over the Amazon and Congo rainforest regions. It is concluded that empirical corrections in earlier Aquarius algorithm versions may be impacting the physical understanding of the observed residuals.
Piepmeier, J. (26-Mar-12). The focus of this talk is whether or not signatures of observed deflection ratios can be reproduced. The current calibration model, RF model, and deflection ratios are investigated, and a potential for improvement is presented.
Gourrion, J., Tenerelli, J., and Sébastien, G. (16-Apr-13). The Soil Moisture and Ocean Salinity (SMOS) satellite was launched on November 2, 2009 in the framework of the European Space Agency's (ESA's) Earth Explorer opportunity missions. Over the oceans, Sea Surface Salinity (SSS) is retrieved on a global basis with a spatio-temporal sampling appropriate for Ocean dynamics and Earth water cycle studies (Font 2010).
Tsontos, V. and Vazquez, J. (30-Mar-16). This presentation was designed to promote discussion about the large number (143) of Level-3 (L3) datasets with further additions expected upon inclusion of sea surface salinity uncertainty. The PO.DAAC suggests possible re-packaging and/or consolidation of data variables currently in separate files within a given file; for example, place ancillary and other variable (e.g., uncertainty) fields embedded in L3 file as additional parameters (variable array). In addition, the PO.DAAC suggests implementation of two metadata standards frameworks for the V5 dataset, the "Attribute Conventions for Data Discovery" (ACDD) and the "Climate Forecast" (CF) convention, which are important in the remote sensing context.
Kao, H-Y. and Schanze, J. (27-Aug-18). The Aquarius validation data system (AVDS) was developed to monitor and evaluate the Aquarius data quality from version to version. AVDS provided the Aquarius matchup with in situ observations and was useful to examine the global, regional, seasonal and long-term salinity biases in Aquarius data. To continue the salinity data validation from Aquarius to SMAP, AVDS was revised into salinity validation data system (SVDS) based on the data format and the design of the SMAP satellite. SVDS will be used to closely evaluate the SMAP salinity data quality in each version. In this talk, we present the results of the SVDS for the most recent version of SMAP-SSS.
Presented at the 2012 AGU Fall Meeting
Nicolas, R., Yves, Q., Tenerelli, J., Grodsky, S.A., and Bertrand, C. (03-Dec-12). The fresh and neutrally buoyant water plume that forms in the Northwestern Tropical Atlantic from the discharge of the Amazon and Orinoco rivers is a salient oceangraphic feature at the surface of the main developement region of north Atlantic Tropical Cyclones. The plume region is characterized by warmer ocean heat content, deeper thermocline and sub-surface barrier layers associated with the strong surface halocline.
Riser, S. (19-July-10). Overview of salinity as an indicator of the ocean's role in the water cycle and as a variable in ocean circulation. Results from the Argo program, which has successfully mapped the distribution of salinity and its changes over the past 2-3 decades.
Brown, S. and Misra, S. (29-Apr-19). SMAP's radiometer and processing algorithms are identical to Aquarius. However, SMAP's scanning antenna looks at angles well beyond those of Aquarius, which had three fixed-angle horns. To reconcile differences between SMAP and Aquarius, data are limited to 254.65° (i.e., Horn 2). Comparison of monthly data suggests some geometric dependent bias in processing.
Menezes, V. and Phillips, H. (25-Feb-16). Subtropical salinity maximum regions are particularly important because the salty subtropical underwater (STW) is formed by subduction of surface waters in these areas.
Yueh, S., Tang, W., Fore, A., and Hayashi, A. (14-Nov-13). This paper describes Aquarius' version-3.0 Combined Active-Passive (CAP) retrieval algorithm for simultaneous retrieval of surface salinity and wind. The major updates to the CAP V3.0 algorithm include the galactic reflection correction, Faraday rotation (FR) and Antenna Pattern Correction (APC) as well as the geophysical model functions (GMF) of wind, wave and rain impacts.
Ward, B., Sutherland, G., ten Doeschate, A., Reverdin, G. and Font, J. (16-Apr-13). Measurements of upper ocean in-situ salinity were conducted during the STRASSE and MIDAS campaigns, which are contributions to the SPURS salinity experiment. Both of these cruises were conducted in the Sub-Tropical North Atlantic in a strong evaporative region.
Xie, X. and Lin, T. (12-Nov-13). This poster displays the equation for upper ocean salinity balance and describes the role of salinity in carbon dioxide partial pressure.
Meissner, T., Wentz, F., Scott, J., and Hilburn, K. (09-Sep-15). This paper focuses on comparing Aquarius salinity in the tropics with measurements from the ARGO drifter network.
Presented at the 2014 AGU Fall Meeting
Maes, C. and O'Kane, T. (18-Dec-14). The present study aims to isolate the specific role of the salinity stratification in the layers above the main pycnocline by taking into account the respective thermal and saline dependencies in the Brunt-Vaisala frequency, N2.
Chao, Y. and Zhang, H. (16-Apr-13). Validating satellite remote sensing data against in situ measurements is always a complex task.
Presented at the 95th AMS Meeting
Clayson, C.A. (07-Jan-15). The unprecedented availability of sea surface salinity (SSS) data available from satellite measurements from Aquarius and SMOS has the potential to revolutionize our understanding of variability across a number of scales of the Earth's water cycle. However, the usefulness of these data is predicated on both a sound understanding of the uncertainty of the data, and a sound understanding of how the SSS as seen at 1 cm by a satellite-borne radiometer is related to the ocean mixed layer salinity.
Reverdin, G., Reverdin, G., Boutin, J., Martin, N., Kolodziejczyk, N., Gaillard, F., Rolland, J., and Blouch, P. (16-Apr-13). Since 2005, we have deployed SVP-BS drifters and attached floats to measure ocean temperature and salinity at different depths within the top 60 cm layer in order to provide information for calibrating and validating new L-band radiometer satellite data.
Sprintall, J. (24-May-17). A major goal as part of the SPURS-2 field campaign is to understand the characteristics and variability of the upper ocean salinity stratification in the vicinity of the ITCZ and identify the main mechanisms that are responsible for this variability. Our contribution focused on the “mesoscale” box (10-300 km) spatial scale, undertaking upper ocean stratification and velocity measurements that will help provide some regional context for the nested small-scale and single-point moored measurements.
Sprintall, J. (12-Mar-18). In this study, the author looks at (1) quantifying the vertical and horizontal structure of variable, large-scale upper ocean circulation and water masses in the SPURS-2 region and (2) determining what regional scale processes are responsible for the evolution and presence of upper ocean salinity stratification.
ten Doeschate, A., Sutherland, G., Font, J., Reverdin, G., and Ward, B. (26-Feb-14). This poster presents results from the deployment of the Air Sea Interaction Profiler during two research campaigns within the framework of the SPURS ocean experiment: STRASSE (August/September 2012) and MIDAS (March/April 2013).
Presented at the 2014 AGU Fall Meeting
Tai, J.H. and Wong, G.T.F. (18-Dec-14). 702 CTD profiles were collected in the subtropical northern South China Sea at and in the vicinity of the SouthEast Asian Time-series Study (SEATS) station (18.2°N, 115.8°E) between 17.5 and 18.5°N and 115.3 and 116.3°E in 64 cruises in 1997 to 2013. The hydrographic structure of the upper water above the permanent thermocline may be classified into 4 principal types: (a) classic type (an almost isopycnic upper water); (b) stepwise type (with one or more small but significant step-increases in σθ in the upper water); (c) graded type (an approximately constant depth gradient in a monotonic increase in σθ in the upper water); and (d) mixed type (a combination of the stepwise and graded types).
Anderson, J.E. and Riser, S. (24-Feb-16). The input of freshwater to the ocean through precipitation is an important component of the global hydrologic cycle. Using salinity as a proxy, satellites and the Argo array have provided new insights into the larger-scale, integrated responses of the ocean to rainfall.
Narvarte, M.A., González, R.A., and Williams, G. (17-Nov-15). Field measurements of sea surface temperature were attempted to be used to evaluate the performance of the standard sea surface temperature algorithm of the New IR Sensor Technology (NIRST).
Gomez, J.J. and Cassini, M.H. (12-Nov-13). Northern elephant seals Mirounga angustirostris are among the most sexually dimorphic and polygynous species of all mammals, and they show spatial segregation between males and females. The objective of this work was to correlate female and male foraging distributions of these seals with main climatic variables at a biogeographical scale in North Pacific and Arctic waters.
Rainville, L. (12-Mar-18). Since the first SPURS-2 cruise in June-July 2016, the Schooner Lady Amber has deployed 100 Surface Velocity Drifters and recovered, serviced, and redeployed several Wave Gliders, Seagliders, and Mixed Layer Lagrangian Floats. Two more cruises are scheduled in 2018 (March-April and May-June) with the potential for additional transit and deployments on the way to the South Pacific (or home) in June-July 2018.
Bruscantini, C. (13-Nov-14). In December 2013, Aquarius official soil moisture maps were released worldwide. Aquarius' co-located radar and radiometer instruments give a unique activity for space-born active/passive fusion retrieval development, of special interest for the forthcoming SMAP mission.
Riser, S.C. and Yang, J. (12-Mar-18). A number of profiling floats deployed in SPURS-2 are equipped with PAL sensors capable of sensing wind and rainfall along the trajectories, and there is evidence of a strong seasonal rain signal that is roughly consistent with the variability in mixed-layer salinity. Further refinement and comparison with other SPURS-2 datasets is required in order to produce a complete picture of the large-scale upper ocean variability in the region on seasonal time scales.
Presented at the 2016 AGU Fall Meeting
Cabot, F., Anterrieu, E., Kerr, Y.H. (16-Dec-16). Since the launch of the SMOS mission in 2009, two other satellites carrying L-band radiometers joined it on orbit. Aquarius was launched in June 2011 and SMAP in January 2015. Unfortunately, Aquarius ceased operation later that year. All 3 instruments have been operating simultaneously between April and June 2015. Although this golden age of L-band on orbit radiometry was short lived, it allowed for sound comparison of the performances of these 3 radiometers. Moreover, its untimely termination emphasizes the need for reliable inter calibration to build long term consistent archives of brightness temperature and higher level products.
Presented at the 2018 AGU Fall Meeting
Reager, J.T., Fournier, S., Vazquez, J., and Dzwonkowski, B. (13-Dec-18). Since its launch in 2015, NASA's Soil Moisture Active Passive (SMAP) mission has provided groundbreaking information on the nature of surface soil moisture globally. Additionally, new opportunities have arisen to retrieve sea surface salinity (SSS) from SMAP. Here, we present a suite of recent research funded by NASA's Science Utilization of SMAP (SUSMAP) program demonstrating the value of SMAP land and ocean data products to study land-sea linkages around the Gulf of Mexico region.
Vazquez, J., Gomez-Valdes, J., Bouali, M., Gentemann, C., and Tang, W. (30-Apr-19). Data from a solar-powered, unmanned surface vehicle, Saildrone, is compared to SMAP sea surface salinity (SSS) data during Apr-Jun 2018. The JPL SSS product shows overall positive biases while the Remote Sensing Systems (RSS) product @ 40 km and @ 70 km shows negative biases. Signal-to-noise ratios for SSS data were fairly low, possibly due to land contamination. SSS coherence data are consistent with coastal upwelling scales while spectral slopes are consistent with mesoscale to sub-mesoscale variability.
Meissner, T., Wentz., F., and Scott, J. (31-Mar-15). An update on the Geophysical Model Functions (GMF) for Aquarius data Version 3.4.
Hong, L. and Gales, J. (31-Mar-15). This talk addresses the residual bias in SSS in Version 3.4.1, which is slightly positive for all beams. The possibility of using a rain filter to mitigate this bias is discussed.
Hong, L. (29-Mar-16). The overview covered updates to Aquarius V4.2 data including the addition of spiciness, the rain impact model (RIM), updated products for random / systematic uncertainty, and the Canada Meteorological Center (CMC) sea surface temperature ancillary data set. Two sub-versions of V4.2 (V4.2.1 and V4.2.1) were discussed: V4.2.0, which included an exponential drift correction and HYCOM-derived bias wiggle correction, and V4.2.1, which included an exponential drift correction and instrument-based wiggle correction. In summary, sea surface temperature from CMC reduces the standard deviation of residual sea surface salinity retrieval error while orbital biases are unchanged. Neither conventional wiggle flattening nor instrumental wiggle correction change latitudinal variation, which changes over season. There are some residual galactic effects in the southern hemisphere, especially in ascending passes.
Hong, L. (18-Sep-17). A comprehensive walk-through of the iterations of the Version 4 Aquarius data. This includes radiometer calibration implements corrections derived against a forward model to compensate radiometer gain drifts and some other possible unknown (instrumental) behaviors.
Zhang, H. and Chao, Y. (26-Feb-14). The Aquarius satellite measured sea surface salinity is validated against in situ measurements collected from the SPURS (Salinity Processes in the Upper Ocean Regional Study) field experiment during September 2012 and October 2013.
Tang, W., Fore, A., Yueh, S., Lee, T., Hayashi, A., Sanchez-Franks, A., and Baranowski, D. (23-July-17). Sea surface salinity (SSS) retrieved from SMAP radiometer measurements is validated with in situ salinity measurements collected from Argo floats, tropical moored buoys and ship-based thermosalinograph (TSG) data. SMAP SSS achieved accuracy of 0.2 PSU on a monthly basis in comparison with Argo gridded data in the tropics and mid-latitudes.
Guerrero, R., Fenco, H. Reta, R., Mercado, A., and Cozzolino, E. (12-Apr-12). Overview of validation of Aquarius sea surface salinity (SSS) exercise including: use of Level 2 grid SSS field using Version 1.2.2 and comparing it to Level 3 data; comparison of SSS error to regional climatology; evaluation of error; and focusing on the Rio de la Plata plume.
Riser, S. and Drucker, R. (13-Nov-13). In this study, the authors validated Aquarius v2.0 level-2 sea surface salinities against Argo near-surface salinities for the period 27-Aug-11 through 31-Jul-13.
Chao, Y. and Zhang, C. (14-Nov-13). In situ measurements collected from the SPURS (Salinity Processes in the Upper Ocean Regional Study) field experiment during September 2012 - October 2013 were used in this study to validate the Aquarius retrieved sea surface salinity.
Chao, Y., Zhang, H., Centurioni, L., Farrar, T., Fratantoni, D., and Hodges, B. (12-Nov-14). Using multiple independent in situ measurements, the accuracy for the Aquarius retrieved sea surface salinity in the SPURS region is assessed, and compared to the accuracy assessed by the standard Argo profiling float. Using four independent data types, we can select any three data types to perform triple-point analysis to derive the weekly Aquarius error in the range of 0.13 to 0.14 psu, which is already smaller than the allocated monthly error of 0.16 psu.
Drucker, R.S. and Riser, S. (26-Feb-14). In this presentation, the authors validate Aquarius v2.0 level-2 sea surface salinities against Argo 5 m salinities for 27 Aug 2011 through 31 Jul 2013, using 16,625 collocated Argo/Aquarius data pairs.
Rivas, N. (17-Nov-15). A project summary for "Validation of data from the SAC-D / AQUARIUS mission: Application to the knowledge of vegetation water stress".
Tauro, C., Hejazin, Y., Jacob, M., and Jones, L. (11-Nov-14). This poster presents a description of the algorithm and results of a comprehensive on-orbit validation using coincident ocean wind speed retrievals provided by Remote Sensing Systems, Inc.
Fore, A., Yueh, S., Tang, W., Stiles, B., and Hayashi, A. (23-July-17). In this work we use the Rapid Scatterometer (RapidScat) and Stepped Frequency Microwave Radiometer (SFMR) to further validate these SMAP radiometer-only high-wind speed retrievals.
Button, N. and Subrahmanyam, B. (17-Apr-13). Western boundary currents are important to study because they influence regional climates and may impact climate change. The Agulhas Current, in particular, is vital to transport of heat and salt from the Indian Ocean to the Atlantic, especially through Agulhas rings. In order to better understand and assess the role of these rings in the global climate system, accurate measurements of the salinity within the current must be made.
Gonzalez-Zamora, A., Sanchez, N., Martinez-Fernandez, J., and Gumuzzio, A. (31-July-15). A comprehensive spatial and temporal validation of long-term dataset of SMOS (Soil Moisture and Ocean Salinity) and Aquarius-derived soil moisture estimates was made using two in situ networks (REMEDHUS and Inforiego) within the Duero River Basin (Spain).
Presented at the 2014 AGU Fall Meeting
Ballabrera, J., Turiel, A., Salvador, J., Fernández, P., and Font, J. (18-Dec-14). To fill the bridge between the skin depth (one cm penetration depth) of the satellite measurements and the uppermost reliable measures (between 5 and 10 meters below the surface) from the Argo floats, a new generation of surface drifters has been designed and deployed in various oceans of the world. Here the drifters deployed during Malaspina Campaign, and their impact in the validation of the various SMOS prodcts, are described.
Zabolotskikh, E. and Chapron, B. (17-Apr-15). A new algorithm is derived for rain rate (RR) estimation from Advanced Microwave Sounding Radiometer 2 (AMSR2) measurements taken at 6.9, 7.3, and 10.65GHz. The algorithm is based on the numerical simulation of brightness temperatures (TB) for AMSR2 lower frequency channels, using a simplified radiation transfer model.
M. Oltmanns, M., Karstensen, J., Moore, G.W.K., and Josey, S.A. (08-Nov-18). The atmospheric response to increased sea surface temperature (SST) implies that there could be a positive feedback that can support its persistence across seasons. Freshwater influences the mixed layer depth by strengthening stratification. This can affect the SST and, in turn, have impacts on large-scale atmospheric dynamics. The SST anomalies that propagate throughout the year can intensify through reemergence and atmospheric feedbacks. Thus, a cooling signal could persist beneath the surface during summer and amplify in subsequent winters. This has been observed when fresher years are followed by an increase in storms, more heat loss and cold air advection. After fresh years, there is an enhanced mixing along cold currents, and reduced mixing along the warm currents. Increased future fretting could trigger stormier and colder winters without necessarily requiring a decrease in deep convection.
Bayler, E.J. and Ren, Li. (25-Feb-16). When employing satellite sea-surface salinity (SSS) observations in studies of observed and modeled ocean variability and change, assessments must consider the variability and uncertainty contained within the satellite SSS data that may or may not reflect physical processes.