摘要
2020年6月8—9日湖南出现一次大范围的致灾暴雨天气过程(以下简称“6.9”过程),导致山体滑坡、重度洪涝等次生灾害,造成8人死亡(或失踪)。此次过程主、客观降雨量预报暴雨落区及强度均出现较大偏差。该文利用常规观测资料、NCEP逐6 h再分析资料,通过引入HYSPLIT4.0模式模拟,从环流背景、水汽特征、环境场条件等进行了偏差及成因探讨。结果表明:强降雨中心较分散,各模式对暴雨量级以上降雨空报漏报严重。高低空急流与低空涡旋的有利配置是导致“6.9”暴雨的主要影响系统,高空西风急流显著加强、低空两支暖湿气流汇合时段与降雨加强时段一致。暴雨区中低层水汽以少见的气旋式涡旋路径传输,这支以涡旋形式输送的偏东气流主流模式均未能捕捉到,这可能是导致“6.9”暴雨落区漏报的直接原因。暴雨区中低层均存在四支水汽传输通道,水汽源地主要为孟加拉湾和南海。水汽输入主要来自南边界,西边界次之,暴雨区域内水汽收入为正;南边界、西边界水汽输入呈同位相特征,波峰时段与暴雨时段相对应,水平水汽通量辐合是“6.9”暴雨区水汽来源的主要方式。强的上升运动和低层辐合、高层辐散有利配置存在一定的时间差;垂直螺旋度中心轴线随高度向南倾斜,位涡及对流不稳定参数大值区与暴雨落区存在偏差。大暴雨中心单站物理量特征表明,暴雨发生时有大的对流潜势,大气为下暖湿上干冷的不稳定层结,湿层高度下降至对流层低层,垂直风切变也较小。
There was a wide range disaster heavy rainstorm process in Hunan from June 8 to 102020.It led to secondary disasters such as landslides,severe floods,8 deaths(missing).In this process,there is a large deviation in the rainstorm falling area and intensity of subjective and objective precipitation prediction.By using the conventional observation data,NCEP 6 hourly reanalysis data,and by introducing the HYSPLIT 4.0 model simulation,The deviation are discussed from the circulation background,water vapor characteristics and environment conditions.The results showed:The centers of heavy rainfall are scattered,there are seriously both high false and missing alarm rates in all of model rainfall forecast.The favorable configuration of high and low-level jet and low-level vortex is the main influencing system leading to the“6.9”rainstorm,The upper westerly jet is significantly strengthened,and the convergence period of the two warm and humid streams at low altitude is consistent with the strengthening period of rainfall.The water vapor in the middle and lower layers of the rainstorm area is transmitted in a rare cyclonic vortex path,and the easterly mainstream mode transmitted in the form of vortex can not be captured,which may be the direct reason for the“6.9”rainstorm area missing.There are four water vapor transmission channels in the middle and lower layers of the rainstorm area,and the water vapor sources are mainly the bay of Bengal and the South China Sea.The water vapor input mainly comes from the south boundary,followed by the west boundary,and the water vapor income in the rainstorm area is positive;The water vapor input at the South and West boundaries shows the same phase characteristics,the peak period corresponds to the rainstorm period,and the convergence of horizontal water vapor flux is the main way of water vapor source in the“6.9”rainstorm area.There is a certain time difference between the strong upward movement and the favorable configuration of low-level convergence and high-level divergence;The central axis of vertical helicity tilts southward with height,and the large value area of potential vorticity and convective instability parameters deviates from the rainstorm area.The physical quantity characteristics of a single station in the center of a heavy rainstorm show that there is a large convective potential when the rainstorm occurs,the atmosphere is an unstable stratification of warm and wet at the bottom and dry and cold at the top,the height of the wet layer drops to the lower troposphere,and the vertical wind shear is also small.
作者
刘红武
胡燕
张海
唐明晖
蔡瑾婕
陈红专
LIU Hongwu;HU Yan;ZHANG Hai;TANG Minghui;CAI Jingjie;CHEN Hongzhuan(Hunan Meteorological Observatory, Changsha 410000, China;Hunan Key Laboratory of Meteorological Disaster Prevention and Reduction, Changsha 410007, China;Huaihua Meteorological Observatory of Hunan Province, Huaihua 418000, China)
出处
《灾害学》
CSCD
北大核心
2022年第2期117-124,155,共9页
Journal of Catastrophology
基金
中国气象局预报员专项(CMAYBY2017-050,CMAYBY2020-085)
2021年中国气象局创新发展专项(CXFZ2021Z033)子项目“2020年湖南主汛期三次不同类型暴雨过程水汽来源及输送特征分析”
湖南省科技厅重点领域研发计划项目(2019SK2161)
湖南省业务能力建设(NLJS14)。
关键词
致灾暴雨
预报偏差
低涡
水汽输送和收支
动力条件
湖南
disastrous rainstorm
forecast deviation
vortex
transport of water vapor
budget dynamic conditions
Hunan
作者简介
第一作者:刘红武(1982-),女,汉族,湖南涟源人,正研级高级工程师,主要从事灾害性天气预报与研究工作,E-mail:45877780@qq.com;通讯作者:胡燕(1980-),女,汉族,湖南永州人,高级工程师,主要从事短中期预报业务技术研究,E-mail:16491614@qq.com。
