Development of Asymmetric Convection in a Tropical Cyclone under Environmental Uniform Flow and Vertical Wind Shear  

作　　者：Yubin LI Yuncong JIANG Johnny C.L.CHAN Kevin K.W.CHEUNG 

机构地区：[1]School of Atmospheric Physics,Nanjing University of Information Science&Technology,Nanjing 210044,China [2]Asia-Pacific Typhoon Collaborative Research Center,Shanghai 201306,China [3]School of Energy and Environment,City University of Hong Kong,Hong Kong 999077,China [4]School of Emergency Management,Nanjing University of Information Science&Technology,Nanjing 210044,China

出　　处：《Advances in Atmospheric Sciences》2024年第12期2399-2418,共20页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant number 42075072);support from The Startup Foundation for Introducing Talent of the Nanjing University of Information Science and Technology.

摘　　要：Idealized numerical simulations have been carried out to reveal the complexity in the development of asymmetric convection in a tropical cyclone(TC)under the influence of an environment with either uniform flow,vertical wind shear(VWS),or both.Results show that rainwater is enhanced to the right of the motion in the outer rainband,but such enhancement occurs in the upshear-left area of the inner-core region.Additionally,due to the asymmetries introduced by environmental flow,wavenumber-1 temperature and height anomalies develop at a radius of~1000 km in the upper levels.A sub-vortex aside from the TC center encompassing the wavenumber-1 warm center appears,and asymmetric horizontal winds emerge,which,in turn,changes the storm-scale(within 400 km)VWS.Deep convection in the inner core closely follows the changing storm-scale VWS when its magnitude is larger than 2 m s^(-1) and is located downshear of the storm-scale VWS in all the experiments with environmental flow.In the outer rainbands,the maximum boundary layer convergence is mainly controlled by the direction of motion and is located in the rear-right quadrant.These results extend upon the findings of previous studies in three aspects:(1)The discovery of the roughly linear combination effect from the uniform flow and large-scale VWS;(2)The development of upper-level asymmetric winds on a 1000-km scale through the interaction between the TC vortex and environmental flow,resulting in changes in the storm-scale VWS pattern within the TC area;(3)The revelation that TC asymmetric convection closely aligns with the direction-varying storm-scale VWS instead of the initially designated VWS.

关 键 词：tropical cyclone environmental flow vertical wind shear asymmetric convection inner core outer rainband 

分 类 号：P444[天文地球—大气科学及气象学]