An Improved Cyclogenesis Potential and Storm Evolution Parameter for North Indian Ocean

Abstract

Flawless subseasonal prediction of tropical cyclogenesis and evolution over the narrow basin of North Indian Ocean (NIO) demands accurate rendition of the crucial parameters that influence the development of cyclonic storms. While many genesis potential indices are used for climatological monitoring and prediction of cyclogenesis globally, their skill in subseasonal prediction of individual storm development, especially near coastlines are limited. Thus, an improved genesis potential parameter (IGPP) is introduced in this study which can capture both cyclogenesis and daily evolution of cyclonic systems over NIO. The IGPP is a revised version of Kotal-Genesis Potential Parameter (KGPP) implemented by India Meteorological Department (IMD) for short-range operational cyclogenesis prediction over NIO. Daily averaged ERA-5 and ERA-Interim data sets are used for analysis and comparison of selected cyclonic storms over NIO for the period 1989–2018. Results reveal that false alarms and overestimation of values present in KGPP are remarkably reduced by using IGPP for all the analyzed storms. Moreover, IGPP outperforms KGPP in distinguishing between developing and nondeveloping storms by accurately representing the storm genesis, evolution, rapid intensification and intensity variations. Thus IGPP can be implemented operationally for improving the real-time prediction of cyclogenesis and storm evolution over NIO.