Variability of salt flux in the Indian Ocean during 1960–2008

This paper describes near-surface horizontal salt flux in the Indian Ocean during 1960–2008 using the Simple Ocean Data Assimilation Reanalysis version 2.2.4. The long term mean salt flux shows seasonal reversals that are more pronounced in the northern Indian Ocean than in the southern Indian Ocean. Mean zonal salt flux is of a higher magnitude than the mean meridional salt flux. Wyrtki jets influence zonal salt flux in the equatorial region. Meridional salt flux is northward along the northeast (NE) African coast and western Bay of Bengal (BoB) during the southwest monsoon season. The opposite holds during the NE monsoon season. Empirical orthogonal function analyses of salt flux show that the Indian Ocean Dipole (IOD) primarily controls interannual variability with flux being westward during positive dipole events and eastward during negative dipole events. The co-occurrence of IOD with the El Niño Southern Ocean results in enhanced salt flux especially along the equatorial region. Spatially, the most variable regions are the NE African coast, eastern Arabian Sea, BoB and equatorial regions. This study will help interpret salinity data for the Indian Ocean from the recently launched Soil Moisture Ocean Salinity and Aquarius satellite salinity missions.