February 23-28, 2014
Honolulu, HI USAhttp://www.sgmeet.com/osm2014/default.asp
Held at the Ocean Sciences Meeting in February 2014, the Ocean Salinity and Water Cycle Variability and Change Session
(073) highlighted a wide range of current research investigating ocean variability and change related to ocean salinity, an important driver of ocean circulation and a key indicator of the global water cycle. Content was focused on observing platforms that provide comprehensive salinity data while extending the scope of ocean and climate research such as the SMOS (Soil Moisture and Ocean Salinity) satellite (launched in November 2009) and the Aquarius/SAC-D satellite (launched in June 2011). These satellite observations are complemented by in-situ observations from the Argo array, which measures sub-surface salinity (and temperature) and the process-oriented field experiment SPURS (Salinity Processes in the Upper Ocean Regional Study, 2012-2013) in the salinity maximum of the North Atlantic.
These recent observations, along with historical measurements, are revolutionizing the view of the ocean on short (hourly, daily to seasonal) and longer (climate, >30-year) timescales. The session involved studies on oceanic variability and change, using observational and model-based approaches, over all timescales and with a key focus on salinity along with temperature and other ocean-state variables. View the agenda
Documents: 68Rosenberg, 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). 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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). 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Lee, T., Lagerloef, G., Kao, H-Y., 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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
. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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). 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. 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.