广西天等县“5·28”极端特大暴雨中尺度成因初探  

Preliminary study on the mesoscale cause of an extreme rainstorm in Tiandeng County, Guangxi on May 28

作　　者：李华实 马智 黄秋丰 陆小晓 农明哲 Li Huashi;Ma Zhi;Huang Qiufeng;Lu Xiaoxiao;Nong Mingzhe(Chongzuo Meteorological Bureau,Chongzuo Guangxi 532200,China)

机构地区：[1]崇左市气象局,广西崇左532200

出　　处：《气象研究与应用》2022年第1期101-106,共6页Journal of Meteorological Research and Application

基　　金：广西壮族自治区崇左市科技项目(崇科攻2021ZC009)。

摘　　要：运用常规气象观测资料、ERA5再分析资料,对广西天等县2019年“5·28”极端特大暴雨过程进行中尺度成因进行探究。结果表明,此次极端强降水在强盛的南亚高压反气旋辐散中心区域以及高空槽加深东移引导低层低涡和辐合切变线缓慢南压的大尺度环流背景下发生,高层强劲的抽吸作用与地面暖低压发展相耦合,有利于地面倒槽锋生,使地面中尺度辐合线长时间维持,触发中尺度对流;湿层较厚,LCL较低,中层有弱干层,垂直温差大,0~6km垂直风切变较小,CAPE较之前有所增大,层结处于不稳定为对流的持续发展提供了较佳的环境条件。低层等假相当位温线密集,呈现出明显的能量锋,锋区随高度上升向北倾斜,偏南和东南气流源源不断补充,形成强水汽辐合,且沿锋面爬升,加上地形抬升作用,降水效率增大,产生强烈降水。Using conventional meteorological observation data and ERA5 reanalysis data, this paper explored the mesoscale causes of an extreme rainstorm process in Tiandeng County, Guangxi on May 28, 2019.The extreme heavy rainfall occurred under the background of the strong South Asian high-pressure anticyclone divergence center and the large-scale circulation in which the high trough deepened and moved eastward, leading the low-level vortex and the convergence shear line to press southward slowly. The strong suction of the upper layer was coupled with the development of warm and low pressure on the ground, which was conducive to the generation of inverted trough frontogenesis on the ground, maintaining the ground mesoscale convergence line for a long time and triggering the mesoscale convection. The wet layer was thick, the LCL was low;there was a weak dry layer in the middle layer;the vertical temperature difference was large, the vertical wind shear of 0~6km was small, the CAPE was larger than before, and the stratification was unstable, which provided better environmental conditions for the sustainable development of convection. The low-level iso-equivalent potential temperature lines were dense, showing obvious energy fronts. The frontal area tilted northward with the rise of height, and the southerly and southeastern air currents continued to supplement, forming strong water vapor convergence and climbing along the frontal surface. Coupled with the topographic uplift, the precipitation efficiency increased and strong precipitation occurred.

关 键 词：暖云降水 垂直风切变 能量锋 水汽强辐合 地形抬升 

分 类 号：P458.121.1[天文地球—大气科学及气象学]