“5·22”广州西北气流控制下特大暴雨过程的中尺度特征分析  

Analysis of the Mesoscale Characteristics of the Heavy Rain ProcessControlled by the Northwest Airflow in Guangzhou on “5·22”

作　　者：贺芸萍 谌芸[1,2,3] 肖天贵 HE Yunping;CHEN Yun;XIAO Tiangui(College of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu,610225,China;National Meteoro-logical Center,CMA,Beijing,100081,China;Southern Marine Science andEngineering Guangdong Laboratory(Zhuhai),Zhuhai,519082,China)

机构地区：[1]成都信息工程大学大气科学学院,四川成都610225 [2]国家气象中心,北京100081 [3]南方海洋科学与工程广东省实验室(珠海),广东珠海519082

出　　处：《成都信息工程大学学报》2023年第4期440-449,共10页Journal of Chengdu University of Information Technology

基　　金：国家自然科学基金资助项目(41930972、41975001、91937301)。

摘　　要：为提高对西北气流控制下暴雨过程的认识,以期为此类暴雨预报提供支撑,利用国家级自动站与区域加密自动站逐小时降水资料,FY-2G卫星和广州多普勒天气雷达探测等资料,采用中尺度分析技术与重要物理量参数计算等方法,分析“5·22”广州特大暴雨过程的中尺度特征。结果表明:降水主要发生在夜间至凌晨,短时强降水占日雨量的比均达75%,强对流性明显。暴雨过程由在西北气流控制下的下滑槽配合对流层低层的西南低空急流及其左侧南移进入广东的深厚低涡切变系统产生,中高层西北气流与低层暖平流形成上干冷、下暖湿的不稳定层结。在高温高湿环境下东北风与西南风形成的地面辐合线触发对流,夜间随着低空急流增强,地面辐合增幅,上升运动加剧。β中尺度对流云团合并加强,后向传播的对流单体在西北气流引导下形成列车效应,伴随着高降水效率的热带低质心暖云降水,导致珠三角强降水产生并持续,从而形成特大暴雨。In order to improve the understanding of the rainstorm process under the control of the northwest airflow and provide support for such rainstorm forecast,this paper uses the hourly precipitation data of national automatic stations and regional encrypted automatic stations,FY-2G satellite data and Guangzhou Doppler weather radar detection data,etc.,by methods of the mesoscale analysis technology and the calculation of important physical parameters to analyze the mesoscale characteristics of the“5·22”Guangzhou torrential rain process.The results show that:The precipitation in this rainstorm process mainly occurred from night to early morning,and the proportion of short-term heavy precipitation accounted for 75%of the daily rainfall,and the strong convection was obvious.The heavy rain process was caused by the down-slope trough controlled by the northwesterly air current,the southwest low-level jet in the lower troposphere and the deep low vortex shear system that moved southward from the left side into Guangdong.The unstable stratification of dry and cold upper layer and warm and humid lower layer is formed by the northwest airflow in the middle and upper lay-ers and the warm advection in the lower layer.In the high-temperature and high-humidity environment,the ground con-vergence line formed by the northeasterly wind and the southwesterly wind triggered the convection.At night,with the strengthening of the low-level jet,the ground convergence increased and the upward movement was intensified.Theβmesoscale convective cloud clusters merged and strengthened,and the backward propagating convective cells formed a train effect under the guidance of the northwest airflow.The train effect,accompanied by the tropical low-mass warm cloud precipitation with high precipitation efficiency,led to the occurrence and maintenance of heavy precipitation in the Pearl River Delta,and finally an extremely large rainstorm was formed.

关 键 词：华南前汛期暴雨 中尺度特征 槽后西北气流 地面中尺度辐合线 列车效应 

分 类 号：P438[天文地球—大气科学及气象学]