An analysis of sea surface temperature and maximum potential intensity of tropical cyclones over the Bay of Bengal between 1981 and 2000

Abstract

From the consideration of thermal energy, the maximum intensity of tropical cyclones largely depends upon the Sea Surface Temperature (SST). In this paper an empirical relationship between SST and Maximum Potential Intensity (MPI) of tropical cyclones over the Bay of Bengal has been developed using a sample of 60 cyclones from 20 years data (1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000). The relationship between SST and MPI is found to be linear. The MPI of each storm is computed using this empirical relationship and compared with observed intensity to examine how close the cyclones come to reaching their MPI. The result shows that about 18% of cyclones reach more than 80% of their MPI and about 38% of cyclones reach more than 50% of their MPI at their peak intensity. In general, cyclones attain about 51% of their MPI. The inter-seasonal variability shows cyclones in the pre-monsoon and the post-monsoon seasons tend to reach a higher percentage of their MPI than in the monsoon season. The inter-annual variability suggests there is appreciable variation in the yearly average of the ratio of observed maximum intensity to the MPI. The MPI could provide useful information to a forecaster about the possible extreme intensity of tropical cyclones, which has direct relevance to disaster management preparedness.

A Dynamical Statistical Model for Prediction of a Tropical Cyclone

“…For instance, in case of Orissa Super Cyclone of October 1999, the peak intensity (140 knots) was 98% of MPI; in the case of the severe cyclonic storm Sidr of November 2007, peak intensity (115 knots) was 79% of MPI. The study (Kotal et al 2009b) showed that SST alone is not a dominant factor for the intensification of a tropical cyclone, but other factors, such as duration of cyclones over the sea and vertical wind shear, also play an important role in controlling the intensity. For the storms over the Indian Sea, the average observed peak intensity of cyclones reach up to 51% of their MPI (Kotal et al 2009b).…”

“…The MPI provides useful information to a forecaster about the possible extreme intensity of tropical cyclones. For the Indian Seas, MPI is derived (Kotal et al 2009b) as:…”

“…Various stages of cyclone forecasting are: (a) genesis, (b) track, and (c) intensity. In a series of recent studies, Kotal et al (2008Kotal et al ( , 2009aKotal et al ( , 2009b proposed an NWP-based objective method for handling various stages of cyclone forecasting over the Bay of Bengal. The method was applied for real-time forecasting of tropical cyclone Nargis of May 2008, and the performance results are presented in this paper.…”

The Indian Coastline: Processes and Landforms

“…Every year, low-pressure systems form in the Bay of Bengal during October-January and move towards the land to strike the coast. The occurrence of cyclones in northern Bay of Bengal has increased by *26 % during the last 120 years (Kotal et al 2009). …”

Relationship between sea surface temperature and the maximum intensity of tropical cyclones affecting Vietnam's coastline

“…The same linear form was later extended for TCs in the Indian Ocean basin by Kotal et al . (), which provides a reasonable estimation of V max in this ocean basin.…”