Interannual and Decadal-Scale Salinity variations in Oceanic Subtropical Gyres

We studied the interannual and decadal variability of sea surface salinity variations in Oceanic subtopical Gyres using the Simple Ocean Data Assimilation (SODA) 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. These results of increasing salinity in high salinity subtropical gyres support the growing evidence of an Evaporation-Precipitation (E-P) pattern amplification on the global scale. Decadal lateral drift of the sea surface salinity maximum was also inferred from SODA reanalysis. Three of five gyres showed significant drift over 60 years within their respective basins. There is evidence of periodicity related to these migrations on multi-decadal timescales. Additionally, global salinity observations from NASA’s Aquarius and ESA’s Soil Moisture and Ocean Salinity (SMOS) missions were used to analyze more recent trends in subtropical gyre salinity, as satellite-derived salinity will be a valuable asset in future studies of the global water cycle.