LAUSR

The spatial and temporal decorrelation scales of sea surface salinity (SSS) have been calculated in the tropical Indian ocean from the satellite measurements including Soil Moisture and Ocean Salinity (SMOS), Aquarius, Soil Moisture Active Salinity (SMAP), and the model output data for the period of 2011–2017. The differences in spatial and temporal scales from different products are discussed and the physical interpretations of the scales of SSS variability are analysed. The results show that, despite the differences in spatial and temporal resolution, there is good agreement between the spatial and temporal scales of SSS field among all products. Large zonal scales (> 2000 km) and temporal scales with strong anisotropy appear in the central of the equatorial Indian Ocean (8° S–15 °S). In addition, the large meridional decorrelation lengths (~ 800 km) and temporal scales with low anisotropy are found in the southern region of the Arabian Sea (0–12 °N) for all products. The decorrelation scales of SSS in these two areas are mainly caused by freshwater flux and salinity advection, respectively. Our results provide new insights into the controlling mechanisms of SSS variability in different regions.