基于区域站雷达观测的黔东南“7.20”极端降水成因分析  

Analysis on the Causes of the Extreme Precipitation in the Southeast of Guizhou on June 20 based on Radar Observation by Regional Station

作　　者：龙天强 俞小鼎[2] 凌燕 余代辉 曹威伍 顾欣 LONG Tianqiang;YU Xiaoding;LING Yan;YU Daihui;CAO Weiwu;GU Xin(Meteorological Office of Southeastern Guizhou,Kaili 556000,Chinma;Training College of Meteorological Cadres of China Melteorological Administration,Beijing 100081,China;Meteorological Office of Kali,Cuizhou Province,Kaili 55600o,China;Meteorological Office of Tongren,Guizhou Province,Tongren 554300,China)

机构地区：[1]贵州省黔东南州气象局,贵州凯里556000 [2]中国气象局气象干部培训学院,北京100081 [3]贵州省凯里市气象局,贵州凯里556000 [4]贵州省铜仁市气象局,贵州铜仁554300

出　　处：《成都信息工程大学学报》2021年第2期214-222,共9页Journal of Chengdu University of Information Technology

基　　金：国家自然科学基金资助项目(41475041);中国气象局预报员专项资助项目(CMAYBY2019-105)。

摘　　要：针对2016年7月20日黔东南西部至东部历时13 h大暴雨天气过程,采用常规观测和雷达、贵州区域站等资料对此次暴雨过程的成因及特征进行分析。结果表明:此次暴雨天气的影响系统主要是500 hPa高空槽、低空急流、地面辐合线,持续12 h低空急流为此次大暴雨的发生输送充沛水汽和不稳定能量;19日黔东南东西沿线地区及周边环境非常有利于大暴雨发生,包含接近1300 J/kg的CAPE值、深厚湿层、强低空急流和异常大的可降水量,降水过程东部水汽通量大辐合强,与该区大范围强降水很好对应;强降水为热带对流型中尺度对流系统MCS,触发机制为超低空强风在黔东南西部及附近遇地形强迫和地面辐合线,黔东南西部至东部长时间有强降水雨团经过而产生大暴雨和特大暴雨,对流云后向传播和低槽遇副高阻挡导致降水系统移动缓慢是长时间降水的直接原因,中尺度涡旋和超级单体是增强降水的因素。A heavy rainstorm stroke the Southeast of Guizhou(Qiandongnan)from west to east on July 20,2016,which lasted for 13 hours.Aiming at this synoptic process,we adopted the conventional observation data,the radar data,the data by a regional station of Guizhou and other relating data to analyse its causes and features.The results are indicated as follows:the rainstorm was principally controlled by 500 hPa high-level trough,low-level jet,and surface convergence line,in which the low-level jet that lasted for 12 hours provided plentiful vapor and unstable energy for it.Several conditions existed in west-east line of Qiandongnan and its surrounding areas on July 19,including the CAPE index close to 1300 J/kg,the moist and deep convection,the strong low-level jet and the abnormally large precipitable water,were benefited to the form of rainstorm.During the precipitation process,vapor in the east showed larger flux and stronger convergence which responded perfectly to the large-scale and severe precipitation in this region.This strong precipitation was belonged to tropical mesoscale convective system(MCS),whose triggering mechanisms are ultra-low-level strong wind encounter topographic forcing and surface convergence line in western Qiandongnan and its surrounding areas.Consequently,a heavy rain cloud cluster passed through Qiandongnan from west to east for a long time so that the rainstorm and the extreme rainstorm occurred.The direct causes for prolonged precipitation contained the backward-propagating convective clouds as well as the slow-moving precipitation system caused by the blocking of the low-level trough by the subtropical anticyclone,while the reinforcing factors of precipitation involved mesoscale vortexes and supercells.

关 键 词：气象学 中尺度分析 极端降水 MCS 低空急流 超低空强风 地形 γ中尺度涡旋 

分 类 号：P458.121.1[天文地球—大气科学及气象学]