Sea surface salinity as measured by SMOS and by surface autonomous drifters

The sea surface salinity (SSS) retrieved from the Soil Moisture and Ocean Salinity (SMOS) mission are systematically lower than ARGO SSS in rainy regions. These freshenings increase (in absolute value) with increasing SSM/I rain rates (-0.2psu/mm/hr) closely collocated in time with SMOS SSS. They are attributed to a stratification of the salinity in the first meters of the ocean surface following a rain event.