Climatology of Energetics of cyclones over Indian Seas

Article history Received: 2 November 2018 Accepted: 10 December 2018 Published: 7 March 2019 An attempt has been made to bring out a climatology of the energetics associated with the tropical cyclones formed over North Indian Seas, viz., the Arabian Sea (AS) and the Bay of Bengal (BOB). Study period is from 1991 to 2013. During this period a total 88 cyclones that developed over the Indian Seas have been considered. These intense systems are categorized on the basis of their formation region and season of formation. It is seen that during the study period, the frequency of formation of cyclones over BOB is twice that over AS which is consistent with the climatology of the regions. Further, it is noticed that over both the regions, they are more frequently formed in the post monsoon period compared to pre monsoon. The trend analysis of the frequency of cyclones forming over both basins, season wise shows that the overall trend for both basins is of just decreasing type. However, for Arabian Sea; the decreasing trend is more apparent in the post monsoon season, whereas in the case of the Bay of Bengal the decreasing trend is more evident in the pre-monsoon season. Various energy terms, their generation and conversion terms have been computed using NCEP/NCAR reanalysis data. Day to day quantitative analysis of these parameters is studied critically during various stages of the cyclones. The composites of these categorized systems are formed and studied. The formative, intensification and dissipation stages showed variations in their energy terms.