Chlorophyll-a, SST and particulate organic carbon in response to cyclone Amphan in the Bay of Bengal

Abstract

This study aims to explore the variation of Chlorophyll-a (Chl-a), particulate organic carbon (POC) and sea surface temperature (SST) before (pre-cyclone) and after (post-cyclone) the cyclone Amphan in the Bay of Bengal (BoB). Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite level-3 data were used to assess the variability of the mentioned parameters. Chl-a concentration was observed to be significantly (t = −3.16, df ≈ 18.03, p = 0.005) high (peak 2.30 mg/m3) during the post-cyclone period compared to the pre-cyclone (0.19 mg/m3). Similarly, POC concentration was significantly (t = 3.41, df ≈ 18.06, p = 0.003) high (peak 464 mg/m3) during the post-cyclone compared to the pre-cyclone (59.40 mg/m3). Comparatively, high SST was observed during the pre-cyclone period and decreases drastically with a significant difference (t = 14, df = 33, p = 1.951e-15) after the post-cyclone period. The results indicated an increase in Chl-a (502%) and POC (240%) with a positive anomaly of 0.55 and 94.11 mg/m3, but a decrease in SST (8.52%) with a negative anomaly of 2.7°C in the BoB.