Monthly variability of chlorophyll and associated physical parameters in the southwest Bay of Bengal water using remote sensing data

Abstract

In the present paper, we have carried out analysis of surface chlorophyll-a concentration in the seas around India obtained using the Indian Remote Sensing satellite IRS-P4 Ocean Colour Monitor (OCM) data. The focus was given to southwest Bay of Bengal where such studies are scanty. The study portraits the chlorophyll-a pattern during July 1999-June 2000. The monthly sea surface temperature (SST) trend and wind patterns using NOAA-NCEP and Quickscat Scatterometer data, respectively, were studied, to elucidate their impact on chlorophyll distribution. This helped to decipher how the reversing monsoon wind induces algal blooming in the surface waters of the study area. Several features like eddies, algal blooms and coastal plumes were observed. Highest mean chlorophyll was observed in January (northeast monsoon) and lowest in May (summer inter monsoon). Adjacent Arabian Sea water found predominantly productive than the Bay of Bengal water. Higher wind speed around 10 m/s in southwest and northeast monsoon shows about two fold increase in chlorophyll concentration to 1.0-2.0 mg/m³ and the SST has shown gradient and decrease of about 1-2ºC in the BoB and off southern India, respectively.