Sub-seasonal variability of tropical cyclone landfall characteristics on the west coast of the Bay of Bengal during October–December:The role of La Nina and El Nino  

作　　者：Anupama Sahoo M.S.Girishkumar 

机构地区：[1]Ministry of Earth Sciences(MoES),Indian National Centre for Ocean Information Services(INCOIS),Telangana,India [2]School of Ocean Science and Technology,Kerala University of Fisheries and Ocean Studies,Panangad,Cochin,India

出　　处：《Tropical Cyclone Research and Review》2024年第4期276-285,共10页热带气旋研究与评论(英文版)

基　　金：the support provided by the MoES-INCOIS fellowships as part of the Ph.D.program.This is INCOIS contribution number 540。

摘　　要：Tropical cyclones(TCs)create more disasters when they make landfall.Climatologically,the west coast of the Bay of Bengal(BoB),one of the most densely populated geographical regions over the globe,is more vulnerable to TC landfall during the primary TC season(Octo-ber–December),with around 72%of TCs originating in the BoB making landfall on the west coast of BoB(WCBoB).However,the evidence for reliable interannual modulation of sub-seasonal variability on landfalling TCs during the primary TC season in the BoB has been explored less.Here,we used the 35 years(1988–2022)of best TC track data from the BoB to investigate this aspect.Those TCs that made landfall on the WCBoB indicate a significant meridional shift between thefirst and second half of the primary TC season in the La Ni˜na regime,with 93%(83%)of TC formed in thefirst(second)half of the season making landfall in the north WCBoB(south WCBoB).Our study reveals that the meridional shift in genesis location and difference in steeringflow between thefirst and second halves of the season is principally responsible for the sub-seasonal variability of landfall location in the La Ni˜na regime,in which former characteristics seem to be determined by southward propagation of Genesis Potential Index(GPI).GPI magnitude is lower in the El Ni˜no regime than in the La Ni˜na regime during the primary TC season,resulting in lower TC activity without sub-seasonal variability in the landfall characteristics in the BoB.

关 键 词：Tropical cyclone LANDFALL ENSO Bay of Bengal Sub-seasonal variability 

分 类 号：P44[天文地球—大气科学及气象学]