Role of physical oceanography parameters in ocean’s biological response with the passage of cyclone Titli in the Bay of Bengal

Titli was the cataclysmic storm to afflict Indian coast during 2018. Tropical cyclones may inflate nutrients on the surface layer of the ocean by entrainment and mixing, as a result, the upper oligotrophic and euphotic layers may be recharged with rich nutrients resulting in triggering phytoplankton blooms and significant increase in primary production. The biological response using the chlorophyll concentration from Oceansat-2 OCM and the Net Primary Productivity from MODIS-A to this cyclone and its relation with the cyclone intensity has been studied. Role of physical oceanography parameters has been studied using multiple satellite-derived parameters like SST, TCHP, SLA, Ekman pumping velocity, wind stress and wind vectors and eddies during the passage of cyclone Titli . The results showed an increase in the surface chlorophyll concentration from 0.08 (before) to 0.32 mg m −3 (after), whereas NPP enhanced from 457 to 1313 mgC m −2 day −1 with an SST drop of ~2.58°C (30.25°–27.67°C). The study confirms that the physical parameters are the key components that influence the biological response in addition to the cyclone intensity.