2020年春末夏初浙江省三次暖区暴雨过程诊断分析  

Diagnostic Analysis of Three Warm-Sector Rainstorms in Zhejiang Province in Late Spring and Early Summer of 2020

作　　者：毛程燕 马依依 顾振海 王健疆 李浩文 MAO Chengyan;MA Yiyi;GU Zhenhai;WANG Jianjiang;LI Haowen(Quzhou Meteorological Bureau,Zhejiang,Quzhou 324000;Guangzhou Meteorological Observatory,Guangzhou 511430)

机构地区：[1]浙江省衢州市气象局,衢州324000 [2]广州市气象台,广州510080

出　　处：《气象科技》2021年第6期903-912,共10页Meteorological Science and Technology

基　　金：浙江省气象局一般项目(2020YB19);衢州市科技局一般项目ZD2020098资助。

摘　　要：利用常规观测资料、FNL再分析资料、FY-2H静止卫星以及双偏振雷达数据,对发生在2020年5月25—26日、29—30日及6月2—3日浙江省的3次暴雨过程(简称"5·25"、"5·29"和"6·2"过程)进行了诊断分析,比较了3次暴雨的落区、强度、成因及云团等差异。结果表明:(1)3次暴雨均发生在高空槽前的低空切变线上,高空槽深浅、中尺度切变线位置、南部急流脉动强弱等因素是造成3次暴雨落区和强度差异的主要原因。(2)暴雨落区位于湿辐合带西侧,700 hPa湿Q矢量散度场负值区对暴雨落区有较好的示踪作用。(3)3次暴雨过程均存在锋生作用和冷暖中心对,"5·25"过程中层锋生先于低层,有弱温度平流,为短历时强降雨,其降水效率低,"5·29"和"6·2"过程则有强冷暖平流,为长历时强降雨,降水效率高。(4)"5·25"过程暴雨云团尺度相对较小且生命史较短,降水稳定;"5·29"过程云体密实、云顶亮温低、回波质心高度高且偏向于混合性降水;"6·2"过程主要为α中尺度对流云团,冷云盖尺度大、存在柱状对流回波、回波质心高度高且偏向于对流性降水。With the utilization of FNL reanalysis data, the Temperature of Black Body(TBB) observed by FY-2 H satellite as well as dual-polarization radar base data, a diagnostic analysis of three warm-sector rainstorms occurred in Zhejiang Province in late spring and early summer of 2020(shorted as “5·25”, “5·29” and “6·2” process respectively) is conducted. The results show that:(1) All the three rainstorm processes occurred under the background of the low-level shear line in front of the upper trough. However, the depth of the upper trough, the position of the mesoscale shear line, and the abnormally strong southwest jet pulsating together caused the varying precipitation area and intensity.(2) The rainstorm area deviated from the west side of the wet Q-vector convergence. The negative value area of the wet Q-vector divergence field at 700 hPa was a good indicator for the rainstorm.(3) There was frontogenesis with a pair of temperature advection centres when the rainstorm occurred. The middle-level frontogenesis occurred before the low level, and there was a weak temperature advection during the “5·25” process, with short-time heavy rainfall and low precipitation efficiency. In comparison, the “5·29” and the “6·2” processes both had strong temperature advection, along with long-lasting, heavy rainfall and high precipitation efficiency.(4) The rainstorm cloud of “5·25” had a small scale with a short life cycle, and the precipitation was relatively stable, while the cloud was dense. The centroid height of the strong echoes was lower during the “5·29” process, which was biased towards a kind of mixed precipitation dominated by cumulus clouds. However, the centroid height of the strong echoes was higher during the “6·2” process, with α-mesoscale convective clouds, large scale cold clouds and columnar echoes, mostly cumulus precipitation.

关 键 词：暖区暴雨 湿Q矢量 锋生 积状云 柱状回波 

分 类 号：P458[天文地球—大气科学及气象学]