A horseshoe salinity pattern in the Indian Ocean

Salinity plays a major role in the global hydrological cycle and climate by modulating upper ocean stratification and sea surface temperature. Past studies have revealed the salinity variation in different major ocean basins from interannual to decadal time scales. However, understanding of upper ocean salinity variation in the Indian Ocean is limited, especially on decadal time scale and thus its global impacts. Our study reveals the presence of a horseshoe pattern in the upper ocean salinity, which varies on a decadal time scale. This pattern is generated from air-sea interaction mechanisms and is linked with Ningaloo Niño. The sea surface temperature anomalies in the southeastern tropical Indian Ocean in relation to Ningaloo Niño triggers the circulation anomaly causing the variation in the precipitation pattern. As a result, the upper ocean freshens or gets more saline and forms as a horseshoe pattern in upper ocean salinity on a decadal time scale. This variation could be useful for better presentation of salinity variation in the Indian Ocean and its associated impacts.