复杂地形影响下鄂东北梅雨锋大暴雨MCS的触发和演变  

Initiation and evolution of MCS of Meiyu frontal heavy rain event in the complex terrain of northeast Hubei

作　　者：贺晓露 汪小康[2] 郝元甲 秦幼文 杨涛 李格 HE Xiaolu;WANG Xiaokang;HAO Yuanjia;QIN Youwen;YANG Tao;LI Ge(Suizhou Meteorological Bureau of Hubei Province,Suizhou 441300;Hubei Key Laboratory for Heavy Rain Monitoring and Warning Research,Institute of Heavy Rain,Wuhan 430205)

机构地区：[1]湖北省随州市气象局,随州441300 [2]中国气象局武汉暴雨研究所暴雨监测预警湖北省重点实验室,武汉430205

出　　处：《暴雨灾害》2020年第6期611-619,共9页Torrential Rain and Disasters

基　　金：国家自然基金青年项目(41705019);随州市科技发展基金项目(202006)。

摘　　要：利用高时空分辨率的ERA5再分析资料、湖北省雷达资料、MICAPS实况观测资料,对2020年7月16日鄂东北梅雨锋大暴雨进行综合分析。结果表明:(1)主雨带沿着山脉呈西北-东南向带状分布,具有持续时间长、累积雨量大、强降水范围集中的特点,有典型的β中尺度特征。(2)地面梅雨锋与925-500 hPa层的切变辐合系统形成了北倾切变系统,这一切变系统在16日白天稳定维持在鄂东北,为此次中尺度系统的发生发展和大暴雨的发生提供动力、水汽和热力条件。(3) MCS发展阶段出现了两种后向传播,即对流单体的后向传播和雨带的后向传播。这两种后向传播导致多个近乎平行排列的东北-西南向短雨带生成并维持,这些短雨带沿着MCS移动形成西北-东南向的"列车带效应"。MCS成熟阶段,雨带中单体移动方向和MCS走向一致,形成"列车效应"。(4)鄂东北地形复杂,在地形强迫作用下,桐柏山附近形成气旋性切变,陈巷站附近形成β中尺度辐合线,二者之间的辐合区有利于对流触发,使MCS西侧或西北侧形成新生雨带;桐柏山-大别山西端的地形阻挡作用,使冷堆形成冷出流,加强了925 hPa冷暖气流在山脉南侧辐合,有利于雨带西南侧的对流单体新生。Based on ERA5 reanalysis data,radar data in Hubei Province and MICAPS observation data,the Meiyu frontal heavy rain event occurred in Northeast Hubei on July 162020 was analyzed.The results show that:(1)The heavy rain event exhibited a northwest-southeast zonal distribution along the mountain range with long duration,high rainfall intensity and concentrative location.The meso-βscale convec⁃tive characteristic of heavy rainfall was obvious.(2)The surface Meiyu front and the shear convergence system between 925 and 500 hPa formed a north dipping shear system.This shear system was stable in Northeast Hubei during the day of 16 to provide dynamic forcing,water vapor and thermal conditions for the occurrence and development of mesoscale system and heavy rain.(3)In the development stage of MCS,there are two kinds of backward propagation.One is the backward propagation of convective cells,and the other is the backward propagation of convective rainbands.These two kinds of backward propagation form several short parallel convective rainbands in a nearly NE-SW direc⁃tion.The short rainbands move along MCS to form a northwest-southeast"band-training".In the mature stage of MCS,the moving direction of cells is consistent with MCS to form a"train effect".(4)A cyclonic shear was formed near Tongbai Mountain and a meso-βconvergence line was formed near Chenxiang station due to the complex terrain of northeast Hubei,which are favorable for the formation of new convec⁃tive rainbands on the west or northwest side of MCS.The terrain blocking effect of Tongbai Mountain and western of Dabie Mountain makes the cold pool form cold outflow.It strengthens the convergence of 925 hPa air flow on the south side of the mountain,which is favorable for the regeneration of the convective cells on the southwest side of the convective rainbands.

关 键 词：梅雨锋暴雨 MCS 后向传播 列车带效应 地形 

分 类 号：P445[天文地球—大气科学及气象学]