Long-term variation of sea surface temperature in relation to sea level pressure and surface wind speed in southern Indian Ocean

Abstract

Sea surface temperature (SST) is an essential parameter associated with fish habitat and changes in oceanic conditions. Long-term SST variation in relation to sea level pressure (SLP) and surface wind speed (SWS) was observed based on the National Oceanic and Atmospheric Administration (NOAA) data of southern Indian Ocean. Mean monthly time series showed that February and November were the warmest and coolest months, respectively. Spatial distribution showed that 0°S–30°S was warm with SST of 20°–30°C, which was higher than that at all other places throughout the year. SLP (> 1010 millibar) and SWS (> 12 m/s) were high at 20°S–40°S and 45°S–50°S, respectively. SST was strongly negatively correlated with SWS but strongly positively correlated with SLP. Long-term yearly time series of SST showed that 2016 and 1948 were the warmest and coolest years, respectively, during the study period. Decadal time series showed that 1978–1987 had the highest decadal change. SST anomalies were almost negative before 1970, positive after 1970, high after 2008, and the highest in 2016. Southwest Indian Ocean was warmer than southeast Indian Ocean in summer and vice versa in winter. SST changes during 1948–2018 were higher than those during 1948–1972 and 1973–2018 for all the 4 months.