台风“鲇鱼”(1617)导致的江西持续性暴雨天气过程成因  

Study on the Causes of Persistent Rainstorm by Typhoon Megi (1617) in Jiangxi Province

作　　者：张娟娟 刘波 张瑛 Zhang Juanjuan;Liu Bo;Zhang Ying(Jiangxi Provincial Meteorological Observatory,Nanchang 330096,China)

机构地区：[1]江西省气候中心,江西南昌330096 [2]江西省气象台,江西南昌330096

出　　处：《气象与减灾研究》2021年第1期16-24,共9页Meteorology and Disaster Reduction Research

基　　金：中国气象局预报员专项(编号:CMAYBY2017-039).

摘　　要：利用常规地面观测资料、卫星和雷达资料以及NCEP再分析资料,对台风“鲇鱼”(1617)在江西引发的持续性暴雨过程的形成原因进行分析。结果表明:台风处于大陆副热带高压和西太平洋副热带高压之间的鞍型场中,系统稳定维持,移动非常缓慢,影响时间长。台风登陆后水汽输送通道仍然维持,低层一支由偏南风和偏东风汇合而成的低空急流,为台风暴雨提供充足的水汽和热量。台风暴雨过程分为两个阶段:第一阶段台风本体降水。登陆后台风暖心结构逐渐遭到破坏,但台风中心附近仍维持上下一致的垂直正涡度柱结构,中低层正涡度区位于台风低压中心和台风北侧风向辐合带,辐合带附近不断有局地中尺度对流云团生成发展。同时,台风高层的气流辐散区与低层台风中心北侧的辐合带相互配合,形成“高层辐散、低层辐合”耦合的垂直环流结构。第二阶段台风与冷空气相结合形成的降水。因冷空气锋区南压而产生的锋生作用,一方面导致台风低压的不稳定能量进一步释放,另一方面使得低层的动力抬升作用增强。台风影响期间,地形对台风降水的增幅有一定的贡献。Using various conventional and surface observation data,radar and NCEP re-analysis data,the causes of a persistent rainstorm by Typhoon Megi(1617)in Jiangxi were analyzed.The results were as follows:1)Typhoon Megi was located between the continent sub-high and the west subtropical high,the systems of which were stable and maintained.The water vapor transport channel was still maintained after the landing.A low level jet formed by the conflowing of southerly and easterly winds provided sufficient water vapor and heat for the rainstorms.The process of typhoon rainstorm can be divided into two stages:the first stage was typhoon body precipitation.The warm core structure of typhoon was gradually destroyed after landing,but the vertical positive vorticity column structure maintained from top to bottom near the typhoon center.The middle and low-level positive vorticity area was located in the convergence zone of the typhoon low-pressure center and its northern wind direction,and local mesoscale convective cloud clusters were generated and developed constantly near the convergence zone.There are obvious divergence areas of wind direction and wind speed in the upper level of typhoon,accompanied by the northern convergence zone of low-level typhoon center,forming the vertical coupling of high-level divergence and low-level convergence.In the second stage,the precipitation was formed by typhoon combined with cold air.The cold air front was pressed southward and the frontogenesis was strengthened.On one hand,the unstable energy of typhoon low pressure was further released;on the other hand,the dynamic uplifting effect of low level was enhanced.During the process of typhoon,topography also contributed to the precipitation increase.

关 键 词：台风暴雨 涡度区 能量锋区 冷空气 地形 

分 类 号：P443[天文地球—大气科学及气象学]