Winter time co-variability of thermal and chlorophyll fronts in the North Bay of Bengal using high resolution satellite data

This study aims to characterize winter time sub-mesoscale thermal and chlorophyll variability using Group of High Resolution Sea Surface Temperature (GHRSST) and Moderate Resolution Imaging Spectroradiometer (MODIS) data respectively in the North Bay of Bengal (17N-23N; 82E-94E). To this end we have computed thermal gradients using monthly mean GHRSST and MODIS data for the period 2006 to 2013. The aim of this study is to find the concurrence of chlorophyll and thermal gradients during winter season. Another interesting question that is aimed to be addressed in this study is to find out under what oceanic and atmospheric conditions thermal and chlorophyll gradients co-exist. It has been found that the thermal gradients are prominent during northern winter months (December to February), and are strongest during January with almost 50-60% of the region dominated by thermal gradients > 0.02 ^oC/km. On the other hand chlorophyll gradients are prominent mainly around the Head Bay region. It is observed that in the Head Bay Region thermal and chlorophyll gradients co-exist temporally, but, in some regions these are displaced spatially. A clear inter-annual variability with some years showing concurrence of thermal and chlorophyll gradients while other years showing no evidence of such co-variability. It is intended to perform an extensive analysis of the patterns of thermal and chlorophyll gradients and find the air-sea interaction processes associated with them. For this purpose satellite observations of met-ocean variables (e.g. sea surface winds, sea level anomaly etc.) are additionally analyzed and the results will be presented in the workshop.