基于多普勒天气雷达资料的“6.1”监利极端大风成因分析  

Cause analysis of an extreme gale event occurred in Jianli on 1 June 2015 based on Doppler weather radar data

作　　者：唐明晖 姚秀萍[2] 杨湘婧 徐靖宇 

机构地区：[1]湖南省气象台,长沙410118 [2]中国气象局干部培训学院,北京100081 [3]湖南省郴州市气象局,郴州423000

出　　处：《暴雨灾害》2016年第5期393-402,共10页Torrential Rain and Disasters

基　　金：中国气象局预报预测核心业务发展专项(20160210);中国气象局灾害天气国家重点实验室开放课题重点项目(2014LASW-A03);公益性行业(气象)科研专项(GYHY201306016)

摘　　要：2015年6月1日湖北省监利县发生一次由下击暴流带来的极端大风天气过程(简称"6.1"监利大风),受其影响,"东方之星"客轮在长江侧翻失事。应用常规观测资料以及加密自动站资料、探空资料、多普勒雷达产品与NCEP再分析资料,分析了"6.1"监利大风过程的环流背景与影响系统,基于雷达资料,重点探讨了其形成原因。结果表明:(1)较强的低层垂直风切变、较低的对流凝结高度等是其发生的有利条件,地面中尺度涡旋、冷锋的发展为其提供了触发机制;(2)"6.1"监利大风由线性多单体风暴造成,其在强盛阶段伴随有超级单体,并连续多个体扫出现中气旋;(3)风暴单体在发展成超级单体后,中气旋旋转速度逐渐增强、底部高度不断降低很可能是龙卷大风产生的先兆;(4)导致"东方之星"失事的下击暴流带来的极端大风(以下简称极端大风)发生前和期间均伴随低仰角速度大值区发展,而极端大风发生时风暴单体的中气旋特征已减弱,此外,极端大风产生前连续5个体扫强反射率因子核出现持续下降;(5)雷达径向速度产品、风暴属性表产品、中气旋属性表产品对"6.1"监利大风临近预警具有重要参考价值,风暴演变趋势、中气旋属性表、低仰角速度大值区在极端大风产生前均呈现出具有一定指示意义的特征。An extreme gale event, hereinafter referred to as ＂6.1＂ gale event, occurred in Jianli, Hubei on 1 June 2015, which is triggered by downburst and caused the capsizing accident of cruise ship ＂Dongfangzhixing＂. Using data from conventional meteorological observations, in- tensive automatic weather station, radiosonde, Doppler weather radar and NCEP reanalysis, we have analyzed the environmental conditions and influencing systems of the ＂6.1＂ gale event, with special emphasis on analyzing its cause based radar data. Results are as follows. （1） The ＂6.1＂ gale event occurred under some favorable conditions such as strong low-level vertical wind shear and lower-than-normal convection condensation level, and it is triggered by the development of mesoscale vortex at ground level and cold front. （2） This event is caused by linear muhieell storm, in which there are accompanied by the supercells and emerged mesocyclones within the serial volume scans. （3） Mesoey- clones revolved in high-speed and their bottom descended continuously after the storm cells developed into supercells, which can he the indi- cation of tornado. （4） The development of a high value center of velocity at low elevation was observed during and prior to the occurrence of the extreme gale （hereinafter referred to as ＂extreme gale＂） caused by the downburst that led to the capsizing accident of cruise ship ＂Dongfang- zhixing＂. The characteristics of mesocyclone in the storm cell have not been clear when the extreme gale occurred. In addition, strong reflec- tivity factor core descended continuously within the five serial volume scans before the extreme gale. （5） Radar radial velocity, storm quality charts and mesocyclone quality charts are important indicators for the early warning of the ＂6.1＂ gale event. And storm evolution, mesocy- clone quality charts and high value center of velocity at lower elevation angle all can be certainly served as a reference before the extreme gale occurred.

关 键 词：极端大风 下击暴流 龙卷 低层速度大值区 中气旋 

分 类 号：P458.123[天文地球—大气科学及气象学]