2010~2022年暖季四川及其周边地区中尺度对流系统的统计特征  

Statistical Features of Mesoscale Convective Systems in Sichuan and Its Surrounding Areas during Warm Seasons from 2010 to 2022

作　　者：陈孟佳 李国平[1] 李山山 CHEN Mengjia;LI Guoping;and LI Shanshan(School of Atmospheric Science,Chengdu University of Information Technology,Chengdu 610225;Wuhan Rainstorm Research Institute,China Meteorological Administration,Wuhan 430205)

机构地区：[1]成都信息工程大学大气科学学院,成都610225 [2]中国气象局武汉暴雨研究所,武汉430205

出　　处：《气候与环境研究》2025年第2期151-167,共17页Climatic and Environmental Research

基　　金：国家自然科学基金,42175002、42105012;四川省中央引导地方科技发展项目,2024ZYD0175。

摘　　要：利用高分辨率卫星的云顶黑体亮温(Black Body Temperature,TBB)资料,对2010~2022年暖季(5~9月)四川及其周边地区(25°N~35°N,96°E~110°E)中尺度对流系统(Mesoscale Convection Systems,MCSs)进行识别、追踪和分类。重点关注了4类MCS(即MCC、PECS、MβCCS和MβECS)的时空分布、活动特征及其对局部降水(夜间/白天)的贡献,并探讨了有利于MCS生成的大尺度环流条件。主要结论如下:β中尺度圆形的对流系统在该地区暖季最为常见。MCS分布较为分散,川西高原、四川盆地东部和南部是对流活动的活跃区,其中南部对流的夜发性显著。MCS的生成在7月最多,5月最少,而6月的对流发展最为旺盛。α中尺度圆形和β中尺度带状的MCS在成熟时具有更大的平均面积、更低的最低云顶温度和更长的生命史。4类MCS表现出发展慢、消亡快的特征,生成的峰值时段集中在午后17:00(北京时间,下同)至18:00。与MCS有关的降水占总降水量的25%以上,对夜间降水的贡献明显高于日间;对流层高空西风急流和反气旋性环流、对流层中低空浅槽、正相对涡度带和气旋性切变以及来自孟加拉湾的水汽为MCS的生成和维持提供了有利条件。Equivalent blackbody temperature(TBB)data from high-resolution satellites were used to identify tracks,and classifies Mesoscale Convective Systems(MCSs)in Sichuan and its surrounding areas(25°N–35°N,96°E–110°E)during the warm season(May–September)from 2010 to 2022.The analysis focuses on the spatial and temporal distribution,activity characteristics of four MCS types(namely MCC,PECS,MβCCS,and MβECS),and their contribution to local precipitation(night/day).The study also examines large-scale circulation conditions that favor MCS formation.The main results are as follows:Circularβmesoscale convective systems are the most common during the warm season in this region.MCS distribution is dispersed,with active convective areas in the western Sichuan Plateau and the eastern and southern Sichuan Basin,where nighttime convection is notably significant.MCS occurrences peak in July and are the lowest in May,with the strongest convection development in June.αmesoscale circular andβmesoscale band MCS have larger mean areas,lower minimum cloud top temperature,and longer lifespans at maturity.All four types of MCS show slow development and fast dissipation,with peak generation times between 1700 LST and 1800 LST in the afternoon.MCS-related precipitation accounts for over 25%of total precipitation,with a significantly higher contribution to nighttime precipitation compared to daytime.Favorable conditions for MCS formation and maintenance include the westerly jet and anticyclonic circulation in the upper troposphere,a shallow trough in the middle and lower troposphere,positive relative vorticity zones,cyclonic shear,and water vapor from the Bay of Bengal.

关 键 词：四川及其周边地区 中尺度对流系统 时空分布 降水 环流背景 

分 类 号：P466[天文地球—大气科学及气象学]