Estimation of tropical cyclone heat potential in the Bay of Bengal and its role in the genesis and intensification of storms

Abstract

In the present study, cyclone heat potential (CHP) in the Bay of Bengal has been estimated for different seasons using Levitus climatology. A good association was noticed between CHP and the efficiency of intensification (i.e the ratio between severe storms to total number of storms (in 5º × 5º grid), for the period, 1877-1977. CHP has been estimated using CTD data collected along the transects 88° E (4º -20º N) and 11.5º N (81º -92º E) during 1993-96 under pre-, during and post- SW monsoon seasons. These estimates are compared with those obtained from TOPEX/Poseidon sea surface height anomalies (SSHA) and TMI (Tropical Rainfall Measuring Mission Microwave Imager) SST using a two layer gravity model. The above estimates are also compared in the Andaman Sea for the 1996 post– SW monsoon season. It appears that the later method underestimates the CHP in the regions of anti cyclonic gyre (ACG). A relation between CHP and SSHA is proposed for the Bay of Bengal which shows a high correlation of 0.79 (N= 67; significant at > 99% level) using the CTD data.