The Oceanic Division of Space Applications Centre of I.S.R.O. would be in a position to help you. You can also contact the Regional Centre of Central Marine Fisheries Research Institute, Vizag.
One of the largest oceanographic in-situ database that includes sea surface salinity is the World Ocean Database (WOD) at NOAA's National Centers for Environmental Information (NCEI).
https://www.ncei.noaa.gov/
WOD is accessible at http://www.nodc.noaa.gov/OC5/WOD/pr_wod.html
The database is being updated quarterly. There is an easy to use tool WODselect that can help identifying the time to which data are current.