2019年主汛期湖南两次致灾暴雨过程对比分析  

Comparative Analysis of Two Disaster-Induced Rainstorms in Hunan Province in Flood Season of 2019

作　　者：刘红武 胡燕 苏涛 刘焕乾 傅承浩 LIU Hongwu;HU Yan;SU Tao;LIU Huanqian;FU Chenghao(Hunan Meteorological Observatory,Changsha 410006,Hunan,China;Hunan Key Laboratory of Meteorological Disaster Prevention and Reduction,Changsha 410006,Hunan,China;Hunan Meteorological Observation Technology Support Center,Changsha 410006,Hunan,China)

机构地区：[1]湖南省气象台,湖南长沙410006 [2]气象防灾减灾湖南省重点实验室,湖南长沙410006 [3]湖南省大气探测技术保障中心,湖南长沙410006

出　　处：《高原气象》2021年第5期1101-1114,共14页Plateau Meteorology

基　　金：中国气象局预报员专项(CMAYBY2020-085);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项目(NLJS14)。

摘　　要：2019年主汛期湖南出现了两次罕见极端暴雨过程,多个气象观测站雨量突破历史极值,共造成十余人死亡(失踪)。利用美国国家环境预报中心的GDAS资料、观测资料以及再分析资料,基于HYSPLIT4(Hybrid Single Particle Lagrangian Integrated Trajectory 4)质点轨道模式追踪及聚类算法,对比分析了2019年6月6-9日(简称过程一)、7月6-9日(简称过程二)两次致灾暴雨过程的异同。结果表明:(1)两次过程具有极端性、持续性、对流性等特点,过程二降雨强度更大、强降雨落区更集中,受灾更严重。(2)两次过程环流形势场存在明显差异,过程一副热带高压强度显著偏强、位置偏北,588 dagpm西脊点较历年同期偏西26个经距,东北冷涡发展深厚,850 hPa急流核风速最大达14 m·s^(-1),且存在双低涡、切变线共同影响;过程二副热带高压稳定维持、脊线偏南超8个纬距,850 hPa上存在显著冷式切变,切变南侧风速大,强烈的冷暖交汇使暴雨的对流性特征更清晰。(3)两次过程中尺度云团的发生演变略有不同,过程一表现为人字形切变线东段触发β中尺度对流云团生成,弱冷空气加入后使其得到有组织化的发展壮大;过程二受西风带长波槽槽前暖湿气流与冷空气交汇,不断有α、β、γ中尺度云团新生、合并发展,多尺度对流云团移经同一地点的“列车效应”造成了强致灾性暴雨发生。(4)水汽来源和分布不尽相同,过程一水汽显著汇合中心位于850 hPa,水汽源地为南海海域,有三条水汽传输通道,主要水汽通道为南海的偏南气流;过程二显著汇合中心位于925 hPa,水汽源地为印度洋,有四条水汽传输通道,主要水汽传输通道来自孟加拉湾的西南气流。In the main flood season of 2019,there were two rare extreme rainstorms in Hunan Province,in which rainfalls of several meteorological observation stations exceeded historical extremes,resulting in more than 10 deaths(missing).By using Global Data Assimilation System(GDAS)data and reanalysis data from the National Centers for Environmental Prediction(NCEP),and observation data,based on the particle trajectory tracking and clustering algorithm from Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT4),the similarities and differences of two disaster-induced rainstorm processes from June 6 to 9(process 1)and July 6 to 9(process 2)in 2019 are comparatively analyzed.The results show that the two processes are characterized by extreme,continuity and convection,and the second process has greater rainfall intensity,more concentrated heavy rainfall areas and more serious disasters than the first one.Besides,there are obvious difference in that circulation field between the two processes.For the process 1,the intensity of the subtropical high was significantly stronger,its location was northerly,and the western ridge point of 588 dagpm was westward by 26 longitudes than that of the same period over the years.The northeast cold vortex developed deeply.The maximum wind speed of the 850 hPa jet stream core reached 14 m·s^(-1),and there were double vortex and shear lines.While for process 2,the subtropical high was stable,the ridge line was south by over 8 latitudes.There was a significant cold shear at 850 hPa,and the wind speed on the south side of the shear was large,which led to the strong cold and warm convergence,causing the convective characteristics of the rainstorm clearer.Furthermore,the occurrence and evolution of mesoscale cloud clusters in the two processes are slightly different.For process 1,there was the eastern section of the herringbone shear line triggering the generation of mesoscale convective clouds,which developed and grew in an organized way after the adding of the weak cold air.For proces

关 键 词：致灾洪涝 中尺度特征 水汽传输 对比分析 

分 类 号：P458[天文地球—大气科学及气象学]