Strengthening of Basin-Scale Ocean Currents in Winter Drives Decadal Salinity Decline in the Eastern Arabian Sea

Observations show a decreasing trend in sea surface salinity during the winter months in 1990-2010 in the southeastern Arabian Sea. To explain the observed salinity decline, we analyze changes in evaporation and precipitation, surface winds, sea level anomaly, and the transport of low-salinity water from the Bay of Bengal to the eastern Arabian Sea via westward flow south of Sri Lanka and a northward coastal current. We find a 2-3 fold increase in the influx of low-salinity water to the eastern Arabian Sea in 1990-2010 associated with strengthening of the Northeast Monsoon Current and the West India Coastal Current. The observed decreasing trend of sea surface salinity in the southeastern Arabian Sea is due to the changes in basin-scale circulation of the northern Indian Ocean in winter.

Automated summary

During the winter months of 1990-2010, observations showed a decreasing trend in sea surface salinity in the southeastern Arabian Sea. This decline was primarily attributed to a 2-3 fold increase in the influx of low-salinity water due to the strengthening of the Northeast Monsoon Current and the West India Coastal Current.