An assessment of two different satellite-derived precipitation products in relation to simulation of sea surface salinity in the tropical Indian Ocean

The focus of the study is on the assessment of two different satellite-derived precipitation products in relation to the simulation of sea surface salinity (SSS) in the tropical Indian Ocean by an ocean general circulation model (OGCM). Precipitation derived from the National Centre for Environmental Prediction (NCEP) has also been used as a benchmark. The period of the simulations covers the years 2003-2007. A comparison with Argo floats suggests that both the satellite products are more effective than NCEP precipitation and a pure satellite product outperforms a merged product. High- and intermediate frequency variability of SSS has been found to be better captured by the satellite products. The equatorial low-salinity tongue formed during a dipole year has been found to be faithfully represented in simulation forced by either of the satellite-derived products. Possible causes for this low-salinity equatorial tongue and the high salinity near Sumatra coast during the dipole year have also been examined. Impact of satellite-derived precipitation has also been assessed in the distribution of barrier layer thickness in the tropical Indian Ocean in the winter months of 2007