Meetings: Documents

Changes in the Seasonal Cycle of Sea Surface Salinity During the Argo-era (2004-2013)
[26-Nov-14] Reagan, J., Boyer, T., Antonov, J., and Zweng, M.
Presented at the 2014 Ocean Salinity Science and Salinity Remote Sensing Workshop
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. We utilize near-surface salinity data from the World Ocean Database (WOD) to compute gridded monthly SSS fields from January 2004 through December 2013. The WOD includes Argo salinities along with other salinity profile data which augment Argo data. In addition to in situ derived monthly analyses, level- 3 monthly data from SMOS and Aquarius are also utilized for the 2010-2013 and 2012-2013 calendar years, respectively. For each calendar year (2004- 2013), a Fourier decomposition is applied and the first and second harmonics are examined for year to year changes in salinity. Furthermore, monthly precipitation data from the Global Precipitation Climatology Project (GPCP) and monthly evaporation data from the Objectively Analyzed air-sea Fluxes Project (OAFlux) are decomposed through a Fourier analysis. The changes in the precipitation and evaporation seasonal cycles are compared to changes in the salinity seasonal cycle. In addition to analyzing and understanding the changes in the seasonal cycle of SSS over the past decade, a brief analysis of the vertical propagation of the seasonal cycle of SSS is conducted.

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