Thermodynamics and Microphysical Characteristics of an Extreme Rainfall Event Under the Influence of a Low-level Jet over the South China Coast

作     者：徐碧裕 黎慧琦 叶朗明 刘显通 饶晓娜 肖辉 徐加民 林青 蒲义良 黄青兰 XU Bi-yu;LI Hui-qi;YE Lang-ming;LIU Xian-tong;RAO Xiao-na;XIAO Hui;XU Jia-min;LIN Qing;PU Yi-liang;HUANG Qing-lan

作者机构：Jiangmen Meteorological BureauJiangmenGuangdong 529030 China Guangzhou Institute of Tropical and Marine MeteorologyChina Meteorological AdministrationGuangzhou 510641 China China Meteorological Administration Tornado Key LaboratoryGuangzhou 510641 China Xinhui Meteorological BureauJiangmenGuangdong 529100 China Guangdong Meteorological BureauGuangzhou 510080 China 

出 版 物：《Journal of Tropical Meteorology》 (热带气象学报（英文版）)

年 卷 期：2023年第29卷第2期

页      面：216-235页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

基　　金：National Natural Science Foundation of China(U2242203,41975138,42275008) Natural Science Foundation of Guangdong Province(2019A1515010814,2021A1515011415) Science and Technology Development Fund Project of Guangdong Meteorological Bureau(GRMC2020M27) Jiangmen Young science and technology talents lifting Project(2022-2023) 

主　　题：low-level jet thermodynamics microphysics heavy rain south China coast 

摘      要：In this paper,the data of Automatic Weather Stations(AWSs),ERA5 reanalysis,sounding,wind profile radar,and dual-polarization radar are used to study an extreme rainfall event in the south China Coast on 11 to 12 May 2022 from the aspects of thermodynamics and microphysical characteristics under the influence of low-level jets(LLJs).Results show that:(1)The extreme rainfall event can be divided into two stages:the first stage(S1)from 0000 to 0600 LST on May 12 and the second stage(S2)from 0700 to 1700 LST on the same *** S1,the rainfall is mainly caused by the upper-level shortwave trough and the boundary layer jet(BLJ),characterized by strong upward motion on the windward side of *** S2,the combined influence of the BLJ and synoptic-system-related low-level jet(SLLJ)increases the vertical wind shear and vertical vorticity,strengthening the *** combination with the effect of topography,a warm and humid southwest flow continuously transports water vapor to farther north,resulting in a significant increase in rainfall over the study area(on the terrain’s windward slope).From S1 to S2,the altitude of a divergence center in the upper air decreases obviously.(2)The rainfalls in the two stages are both associated with the mesoscale convergence line(MCL)on the surface,and the wind field from the mesoscale outflow boundary(MOB)in S1 is in the same direction as the environmental *** to a small area of convergence that is left behind the MOB,convection moves eastward quickly and causes a short duration of heavy *** S2,the convergence along the MOB is enhanced,which strengthens the rainfall and leads to strong outflows,further enhancing the surface convergence near the MOB and forming a positive feedback *** results in a slow motion of convection and a long duration of heavy rainfall.(3)In terms of microphysics,the center of a strong echo in S1 is higher than in *** warm-rain process of the oceanic type characterizes both stage