Spatial variability in sea surfacetemperature and wind-driven coastalupwelling along the southwest coastof India

The coastal environment along the southwest coast of India is influenced by seasonal wind-driven coastal upwelling. The trend of upwelling index (UI) and sea surface temperature (SST) along the southwest coast of India during 1988-2015 were analysed in this study. In order to understand the spatial variation in SST and UI, the entire southwest coast of India was divided into three strata viz. stratum_1 (ST_1, southern part), stratum_2 (ST_2, middle part) and stratum_3 (ST_3, northern part). Temporal analyses of these parameters were carried out for three seasons such as monsoon (June-September), post-monsoon (OctoberJanuary) and pre-monsoon (February-May). In addition to seasonal changes in upwelling, large-scale latitudinal differences in upwelling were observed during this study, which is associated with spatial differences in coastal topography. The upwelling index along stratum_3 has increased after 1995 compared to previous period. Both SST and UI exhibited spatial variation along southwest coast of India. Eventhough, UI is higher during the summer monsoon compared to other seasons, a declining trend in UI during the summer monsoon was found from 1988 to 2015.