Drastic change in dynamics as Typhoon Lekima experiences an eyewall replacement cycle

作     者：Fen XU X.San LIANG Fen XU;X.San LIANG

作者机构：School of Atmospheric SciencesNanjing University of Information Science and TechnologyNanjing 210044China. School of Marine SciencesNanjing University of Information Science and TechnologyNanjing 210044China 

出 版 物：《Frontiers of Earth Science》 (地球科学前沿（英文版）)

年 卷 期：2022年第16卷第1期

页      面：121-131页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0708[理学-地球物理学] 0706[理学-大气科学] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China(Grant No.41975064) the 2015 Jiangsu Program for Innovation Research and Entrepreneurship Groups 

主　　题：Typhoon Lekima multiscale window transform canonical transfer multiscale energetics barotropic/baroclinic instability 

摘      要：Why does the 1909 typhoon,Lekima,become so destructive after making landfall in China?Using a newly developed mathematical apparatus,the multiscale window transform(MWT),and the MWT-based localized mutliscale energetics analysis and theory of canonical transfer,this study is intended to give a partial answer from a dynamical point of *** ECMWF reanalysis fields are first reconstructed onto the background window,the TC-scale window,and the convection-scale window.A localized energetics analysis is then performed,which reveals to us distinctly different scenarios before and after August 8–9,2019,when an eyewall replacement cycle takes *** that,the energy supply in the upper layer is mainly via a strong upper layer-limited baroclinic instability;the available potential energy thus-gained is then converted into the TC-scale kinetic energy,with a portion to fuel Lekima’s upper part,another portion carried downward via pressure work flux to maintain the cyclone’s lower *** the eyewall replacement cycle,a drastic change in dynamics ***,the pressure work is greatly increased in magnitude.A positive baroclinic transfer almost spreads throughout the troposphere,and so does barotropic transfer;in other words,the whole air column is now both barotropically and baroclinically *** newly occurred instabilities help compensate the increasing consumption of the TC-scale kinetic energy,and hence help counteract the dissipation of Lekima after making landfalls.