Impact of Cyclone PHAILIN on Chlorophyll-a Concentration and Productivity in the Bay of Bengal

Abstract

Ocean colour remote sensing is one of the conventional methods in satellite oceanography used to study the biological response of the upper ocean to the tropical cyclones. This paper aims to study the impact of the Very Severe Cyclonic storm PHAILIN, and its consequence on the surface chlorophyll- a concentration distribution in the Bay of Bengal using Oceansat-2 Ocean Colour Monitor (OCM). The impact of this cyclone on ocean primary productivity has been studied using MODIS-A data. Sea surface temperature (SST) plays an important role in the generation of primary productivity along with the other oceanographic parameters; SST patterns in the Bay of Bengal during the cyclone period were studied. From the analysis, it is observed that the chlorophyll- a concentration has increased from 1.08 (before) to 7.06 mg/m 3 after the cyclone with an SST drop of ~3 ° C (29.19 ° C to 26 ° C). The primary productivity has increased from 410.0506 to 779.9814 mg/C/m 2 /day after the cyclone. In addition to the above analysis, an attempt has also been made to study the impact of cyclone intensity on the chlorophyll concentration. The study shows that the comparison between cyclone intensity (CI) and chlorophyll concentration shows a positive relationship.