2018年湖南首场风雹天气成因分析及预警探讨  

Synthetic discussion on the causes and early-warnings of the first wind-hail strong convection weather over Hunan in 2018

作　　者：王青霞 唐明晖 王强[2] 蔡瑾婕 周长青 邓见英 WANG Qingxia;TANG Minghui;WANG Qiang;CAI Jingjie;ZHOU Changqing(Hunan Meteorological Observatory,Changsha 410118;Huaihua Meteorological Observatory of Hunan Province,Huaihua 419599;Loudi Meteorological Observatory of Hunan Province,Loudi 417000)

机构地区：[1]湖南省气象台,长沙410118 [2]湖南省怀化市气象局,怀化419599 [3]湖南省娄底市气象局,娄底417000

出　　处：《暴雨灾害》2020年第1期30-40,共11页Torrential Rain and Disasters

基　　金：中国气象局预报预测核心业务发展专项(CMAHX20160210);湖南省气象局重点项目(XQKJ17A002);湖南省气象局预报员专项(XQKJ19C012);湖南省重点研发计划(2019SK2161)。

摘　　要：利用常规观测资料、NCEP逐6 h再分析资料、FY-2G卫星TBB资料及多普勒天气雷达资料对2018年3月4日湖南首场风雹过程进行综合分析,并探讨其预报预警着眼点,分析结果表明:(1)本次风雹过程先后经历“低层暖平流强迫”和“斜压锋生”两阶段。第一阶段:湖南受强烈发展的暖湿气流影响,对流由地面中尺度辐合线触发,以层积混合型回波为主,东移北上,前侧有线风暴发展;第二阶段:对流由冷空气前沿的锋面触发,以积状云降水回波为主,东移南下,多超级单体风暴发展。(2)该过程SI指数明显偏低、CAPE、DCAPE及垂直风切变明显偏高,使得该次风雹过程具有一定极端性;第一阶段表征雷暴大风的DCAPE的范围更广、强度更强,且中层干层明显,有利于成片雷暴大风的出现;第二阶段湘南的水汽、动力因子较第一阶段增强,但范围相对集中,随冷锋南下,0℃和-20℃层高度下降有利于冰雹的出现。(3)短临预警方面,低仰角速度大值区、大的风暴移动速度、持续多个体扫的中气旋是本次风雹过程最关键的预报着眼点。Based on the conventionally observed data,NCEP 6 hourly reanalyzed data,FY-2G satellite TBB data and Doppler weather radar data,we analyze the causes of the first wind-hail strong convection weather process over Hunan on 4 March 2018,and then explore the early warning focus and predictability for strong hail and thunderstorm gale.The results show:1)The process of wind-hail is divided into two stages,i.e.,the“low-level warm advection forced”and the“baroclinic frontogenesis”.In the“low-level warm advection forced”stage,under the southwest warm and humid flow,wind-hail weather is triggered by the ground mesoscale convergence line and consists of stratified mixed precipitation echoes which is moving to northeast.Line-storm has developed in front of echoes.In the“baroclinic frontogenesis”stage,the radar echo is triggered by cold front and consists of accumulated clouds,moving to southeast.Multiple supercell storms occur at this stage.2)The apparently low SI and high CAPE,DCAPE,and vertical wind shear make the windy weather extreme.Comparing the two stages,in the first one the range of DCAPE is wider and strength is stronger,and dry layer in the middle layer is obvious,which tends to the emergence of thunderstorm gales.In the second stage,vapor and dynamic factors are stronger and more concentrated in southern Hunan.With the cold front moving,the height of 0℃and-20℃isotherms are decreased,which is beneficial to the occurrence of hail.3)The large radial velocity at low elevation,MVT and sustaining mesocyclone are the key points for early-warning of thunderstorms.

关 键 词：风雹 低层暖平流强迫类 斜压锋生类 低仰角速度大值区 

分 类 号：P458.121.2[天文地球—大气科学及气象学]