江西省暖切变线暴雨及其过程中MCS统计分析

Analysis on Characteristic of Rainstorm and Mesoscale Convective System Triggered by Warm Shear Line in Jiangxi Province

利用风云卫星TBB资料,对2012—2021年3—6月江西省暖切变线暴雨及其过程中生成的MCS进行了统计分析。结果表明:(1)暖切变线是低层影响江西省暴雨的重要天气系统之一,基本呈东西走向,多位于29°N~30°N附近。暖切变线暴雨有北多南少的特征,强降水主要发生在暖切变线南侧的西南急流中。(2)中尺度对流系统基本是由西向东移动发展的,6月最多,3月最少,以β尺度的MCS为主,MβCC是暖切变暴雨中最常见的中尺度对流系统。午后和夜间是MCS活动频繁、发展消亡的主要时间段,大部分MβCS在1~2 h左右就可以发展成熟,2 h内迅速减弱消亡,而MαCS生命史相对长一些。(3)鄱阳湖流域、罗霄山脉以及罗霄山脉东部的平原地区,是此类暴雨过程中MCS的主要生成区域,这些MCS东移至赣东北和赣中的东部地区达到成熟,其成熟位置对于预报此类暴雨的落区有一定的指示意义。

Based on TBB data from Fengyun satellite,a statistical analysis of heavy rainfall triggered by warm shear line in Jiangxi Province and MCS generated in the processes from March to June in both 2012 and 2021 was conducted.The results are as follows,(1)warm shear line is one of the important weather systems which affect the rainstorm in Jiangxi Province.Warm shear lines are basically in the east-west direction,and most of them are located near 29°N~30°N.The warm shear line rainstorm has the characteristics of more in the north and less in the south.Heavy precipitation mainly occurs in the southwest low level jet on south side of warm shear lines.(2)Mesoscale convective systems basically develop from west to east,with the most in June and the least in March,dominated byβscale.MβCC is the most common mesoscale convective system in warm shear rainstorms.Afternoon and night are the main time periods when MCS develop and disappear.Most MβCS can develop and mature in about 1~2 hours,and quickly weaken and disappear within 2 hours,while MαCS has relatively long life.(3)The Poyang Lake Basin,the Luoxiao Mountains,and the plains in the east of the Luoxiao Mountains are the main generating areas of MCS during the torrential rain.The locations have certain indications for forecasting rainstorm areas of such torrential rain.