2020年秋季一次冷锋切变影响的滇东南灾害性暴雨过程分析

Analysis of Disastrous Rainstorm Process in Southeast Yunnan Affected by A Cold Front Shear in Autumn 2020

基于常规气象观测资料、NCEP/NCAR FNL 1°×1°再分析资料和卫星资料,对2020年秋季滇东南一次灾害性暴雨过程的环流背景,水汽、热力及动力条件,中尺度对流云团演变特征进行分析。结果表明:副高西进过程中断裂出滇缅高压,滇东南恰好处于两高辐合区内,配合850 hPa切变线和地面冷锋造成此次滇东南暴雨。孟加拉湾和南海两支水汽通道在滇东南上空汇合,且滇东南地区上空大气层结不稳定,有较强的不稳定能量蓄积和剧烈的垂直上升运动,有利于强降水的产生。中尺度对流云团在滇东南地区不断生成与合并且长时间的维持是造成此次区域性暴雨的关键因素。

Based on conventional meteorological observation data,NCEP/NCARFNL 1 ° × 1 ° reanalysis data and satellite data are used to analyze the circulation background,water vapor,thermal and dynamic conditions,and evolution characteristics of mesoscale convective cloud clusters of a disastrous rainstorm process in Southeast Yunnan in the autumn of 2020.The results show that the westward movement of the subtropical high breaks out of the Yunnan Myanmar high,and the Southeast of Yunnan is just in the convergence area of the two high levels.The 850hPa shear line and the surface cold front caused the rainstorm in Southeast Yunnan.The Bay of Bengal and the South China Sea two water vapor channels converge over Southeast Yunnan,and the atmospheric stratification over Southeast Yunnan is unstable,with strong unstable energy accumulation and intense vertical upward movement,which is conducive to the generation of heavy rainfall.The continuous formation and long-term maintenance of mesoscale convective cloud clusters in Southeast Yunnan are the key factors causing this regional rainstorm.