Role of Ocean Heat Content in the Rapid Intensification of Cyclone Amphan over the Bay of Bengal (2020)

A major forecasting challenge in the North Indian Ocean is the rapid intensification (RI) of tropical cyclones, especially in the Bay of Bengal, where coastal communities are extremely vulnerable. The main indicator of cyclone intensification has historically been sea surface temperature (SST). Since it captures the total thermal energy available for cyclone growth outside of the surface layer, subsurface ocean heat content (OHC) has lately been acknowledged as a more accurate metric. This study examines how OHC contributed to Super Cyclonic Storm Amphan's (2020) quick intensification over the Bay of Bengal.We'll examine the atmospheric and oceanic factors that contributed to Amphan's abrupt intensification using Tropical Cyclone Heat Potential datasets, in-situ Argo float observations, and best-track records from the India Meteorological Department (IMD). The findings indicate that OHC values in the intensification region were well above the 60 kJ cm⁻² threshold that is thought to be favorable for RI, exceeding 100 kJ cm⁻². Warm SST (>30°C) and an elevated OHC supplied enough subsurface thermal energy to support the cyclone's intensification from cyclonic storm to super cyclonic storm in less than 48 hours. Even though SST stayed favorable the entire time, Amphan's RI's timing and magnitude were strongly correlated with the unusually high OHC. The study highlights the necessity of incorporating OHC monitoring into Bay operational cyclone forecasting.