An attempt has been made to understand the dynamics behind anomalous cyclogenesis over North Indian Ocean during 2013 cyclone seasons, from an atmospheric energetics point of view. For that various energy terms, their...An attempt has been made to understand the dynamics behind anomalous cyclogenesis over North Indian Ocean during 2013 cyclone seasons, from an atmospheric energetics point of view. For that various energy terms, their generation and conversion terms have been computed using NCEP/NCAR reanalysis data during different phases of the intense cyclonic vortices formed in 2013 over North Indian Seas. It is observed that maximum intensification of all the intense cyclonic vortices was associated with an enhancement in both conversions viz., from eddy available potential energy (AE) to eddy kinetic energy (KE) and zonal kinetic energy (KZ) to eddy kinetic energy (KE). Energetics analysis suggested that during intensification of the storms, dissipation of both eddy available potential energy ( AE )and zonal available potential energy (AZ) have taken place, suggesting the intensification of storms at the cost of AE and AZ. For all of these systems baroclinic eddy kinetic energy conversions i.e. from AE to KE dominates over barotropic eddy kinetic energy conversions i.e. from KZ to KE.Anomalous cyclogenesis in 2013, was partly attributed to a positive anomaly in moist static energy of the environment along with positive anomaly in baroclinic and barotropic eddy kinetic energy conversions during cyclone seasons over the region under study. Release of convective instability in the atmosphere can be partly attributed for anomalous cyclogenesis in 2013.展开更多
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 1...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.展开更多
文摘An attempt has been made to understand the dynamics behind anomalous cyclogenesis over North Indian Ocean during 2013 cyclone seasons, from an atmospheric energetics point of view. For that various energy terms, their generation and conversion terms have been computed using NCEP/NCAR reanalysis data during different phases of the intense cyclonic vortices formed in 2013 over North Indian Seas. It is observed that maximum intensification of all the intense cyclonic vortices was associated with an enhancement in both conversions viz., from eddy available potential energy (AE) to eddy kinetic energy (KE) and zonal kinetic energy (KZ) to eddy kinetic energy (KE). Energetics analysis suggested that during intensification of the storms, dissipation of both eddy available potential energy ( AE )and zonal available potential energy (AZ) have taken place, suggesting the intensification of storms at the cost of AE and AZ. For all of these systems baroclinic eddy kinetic energy conversions i.e. from AE to KE dominates over barotropic eddy kinetic energy conversions i.e. from KZ to KE.Anomalous cyclogenesis in 2013, was partly attributed to a positive anomaly in moist static energy of the environment along with positive anomaly in baroclinic and barotropic eddy kinetic energy conversions during cyclone seasons over the region under study. Release of convective instability in the atmosphere can be partly attributed for anomalous cyclogenesis in 2013.
文摘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.
