“3.21”湖州市强对流天气过程及预报误差成因分析  

Analysis on the Process of Severe Convective Weather and Causes of Forecast Error on 21th March 2020 in Huzhou

作　　者：王丹丹 尹浩 奚雷 许金萍 梁明珠 Wang Dandan;Hao Yin;Xi Lei;Xu Jinping;Liang Mingzhu(Huzhou Meteorological Bureau,Huzhou Zhejiang 313000,China;Anji Meteorological Bureau,Anji Zhejiang 313300,China)

机构地区：[1]湖州市气象局,浙江湖州313000 [2]安吉县气象局,浙江安吉313300

出　　处：《科技通报》2022年第8期11-18,109,共9页Bulletin of Science and Technology

基　　金：湖州市公益性技术应用研究(重点)项目(2020GZ31)。

摘　　要：利用NCEP再分析资料、EC和WARMS预报资料、自动观测站和多普勒雷达资料,分析了2020年3月21日发生在湖州地区的强对流天气过程。结果表明:本次过程分为2个阶段,阶段1(21日15时~22时)为低层暖平流强迫类,低层强烈发展的暖湿平流配合风场扰动、地面辐合线触发形成强对流天气;阶段2(21日22时~22日08时)为斜压锋生类,显著的冷暖平流交汇形成的长时间维持的冷切及地面冷锋、辐合线是强对流天气的有利背景场。典型的“上干下湿”喇叭口结构、明显的中层干层、高的对流层垂直温度递减率和强的垂直风切变是产生本次强对流天气的物理量特征。雷达特征表明多个组织性完好的强对流单体陆续东移形成列车效应,利于形成短时强降水和暴雨等强对流天气。对比分析了EC和WARMS对湖州降雨量的预报效果,WARMS明显优于EC,西南急流的低估和急流出口涡旋辐合的漏报是EC模式明显低估湖州北部降雨量的主要原因。In this paper,the severe convective weather process in Huzhou on 21 th March,2020 was analyzed by using NCEP reanalysis data,EC and WARMS forecast data,automatic observation station data and doppler radar data.The results showed that:the process was divided into two stages.The first stage(15:00 to 22:00 on 21 th) was a low-level warm advection forcing type.The warm and wet advection developed strongly in the low-level,combined with wind field disturbance and ground convergence line triggering,formed a strong convective weather.The second stage(22:00 on 21 th to 8:00 on 22 th) was type of baroclinic frontogenesis.The strong convective weather was favorable for the long time cold shear line caused by the significant convergence of warm and cold advection and surface cold front and convergence line.The typical bell-mouth structure of "dry above and wet below",obvious middle dry layer,high vertical temperature decline rate of troposphere and strong vertical wind shear are the physical characteristics of this severe convective weather.The features of radar showed that multiple well-organized strong convective cells moved eastward consecutively to form the train effect,which was conducive to the formation of short-time heavy rainfall,rainstorm and other strong convective weather.In this paper,the results of precipitation prediction in Huzhou are compared and analyzed.The results showed that WARMS was obviously better than EC.The underestimation of the southwest jet stream and the unreported convergence of the vortex at the outlet of the jet stream were the main reasons why the EC model significantly underestimates the rainfall in the northern part of Huzhou.

关 键 词：强对流 预报误差 低空急流 

分 类 号：P456[天文地球—大气科学及气象学]