冷涡背景下苏北地区连续两次强对流天气过程对比分析  

Comparative Analysis on Two Consecutive Severe Convection Weather Events in Northern Jiangsuunder Cold Vortex Background

作　　者：王伟健 颜佳任 郝玲 朱云凤[1] Wang Weijian;Yan Jiaren;Hao Ling;Zhu Yunfeng(Lianyungang Meteorological Bureau,Lianyungang 222006,China)

机构地区：[1]连云港市气象局,江苏连云港222006

出　　处：《气象与减灾研究》2020年第2期97-105,共9页Meteorology and Disaster Reduction Research

基　　金：江苏省气象局预报员专项(编号:JSYBY202009;JSYBY201811).

摘　　要：利用地面观测资料、天气雷达资料和ECMWF-ERA5逐小时0.25°×0.25°再分析资料,主要从环境条件和触发机制两个方面,对2019年6月8日(简称过程A)、9日(简称过程B)影响江苏省北部的两次冷涡型强对流天气过程进行了对比分析。结果表明:过程A是由暖湿气流引起的短时强降水伴随雷暴大风的湿对流天气;过程B则是在高层西北气流下由干冷平流强迫引起的大风冰雹伴随短时强降水的混合对流天气。过程A,由暖湿气流形成强对流不稳定层结,垂直风切变强度一般,湿层深厚,有利于短时强降水的发生;过程B,中高层的较强干冷平流叠加在低层暖湿平流上而形成强对流不稳定层结,强的垂直风切变位于中低层,配合较强的动力抬升条件,有利于冰雹的发生。两次天气过程的触发机制都是地面辐合线。过程A的预报重点为水汽条件和来自上游的对流系统与当地地面辐合线的耦合;过程B的预报重点为大气的不稳定度和冷涡后部冷空气的干侵入与地面辐合线的耦合。Based on the ground observation data,ERA5 reanalysis datasets and radar datasets,two consecutive severe convection weather events under cold vortex background occurred in northern Jiangsu during 8 June and 9 June 2019(Event A and Event B in abbreviation respectively)were compared mainly from two aspects of environmental conditions and trigger mechanism.The results showed that:Event A was a wet convective weather with short-term heavy precipitation accompanied by thunderstorms and gales caused by warm and humid air;Even B was a mixed convective weather with strong winds and hail accompanied by short term heavy rainfall under the upper northwest airflow forced by dry and cold advection.For Event A,there was a deep moisture convection caused by warm moist flow with certain vertical wind shear condition,a short-time heavy rainfall was observed during Event A process accompanied by strong wind.In contrast,for Event B,there was a mixed convection including strong wind and hail with short-time heavy rainfall caused by dry and cold advections on the middle-high level.These two severe weather events were both triggered by surface convergence lines.In general,the focuses of attention for Event A forecast were the moisture conditions and whether the upwind convective system would couple with the local surface convergence lines when it moved towards Lianyungang district,while for Event B were the potential instability,dry intrusion and surface convergence lines.

关 键 词：强对流 东北冷涡 干侵入 辐合线 海陆风 

分 类 号：P458.2[天文地球—大气科学及气象学]