Ocean Primary Productivity Variation due to the Cyclone: A Case Study at Bay of Bengal

Monitoring ocean primary productivity especially Chlorophyll-a (Chl-a) concentration is important as it contributes to the carbon cycle, global climate change and ocean health study. This study aims to examine the effects of cyclone events on the ocean productivity in the Bay of Bengal (BOB) considering its importance on global climate change. Level 2 SeaWiFS daily data from 2001 to 2010 were used to determine Chl-a concentration and data from the Indian Meteorological Department (IMD) were used to get information and locations of the cyclone events. Variation of Chl-a concentration was determined from the Chl-a concentration maps (pre-, during, and post-cyclone) using several transect lines parallel to the cyclone passages. Results indicated that there is a relationship between the variation of Chl-a concentration and the cyclone events at the BOB but the effect is varied according to the type of cyclone where very severe cyclonic storm (VSCS) has higher impact on Chl-a concentration compared to cyclonic storm (CS) and severe cyclonic storm (SCS). In most cases, Chl-a concentration was increased right after the cyclone event and the influence was observed over a wide area surrounding the cyclone passage.