台风利奇马登陆期间的对流结构特征及对强降雨影响  

Convection Structure and Impact on Severe Precipitation During Landing of Typhoon Lekima

作　　者：陈涛 董林[1,2] 罗玲 杨舒楠 CHEN Tao;DONG Lin;LUO Ling;YANG Shunan(National Meteorological Centre,Beijing 100081;CMA-HHU Joint Laboratory for Hydro-Meteorological Studies,Beijing 100081;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082;Zhejiang Meteorological Observatory,Hangzhou 310000)

机构地区：[1]国家气象中心,北京100081 [2]中国气象局-河海大学水文气象研究联合实验室,北京100081 [3]南方海洋科学与工程广东省实验室(珠海),珠海519082 [4]浙江省气象台,杭州310000

出　　处：《气象》2021年第12期1433-1443,共11页Meteorological Monthly

基　　金：国家重点研发计划(2017YFC150210和2019YFC151040)共同资助

摘　　要：2019年9号台风利奇马在浙江造成极端降水,其中8月9日白天浙江东部受台风外围螺旋雨带长时间影响,9日夜间在台风内核对流影响下降水有显著增强;降水中心与浙江临海地区的天台山、括苍山和雁荡山等地形特征密切相关。GPM(Global Precipitation Measure)卫星遥感反演表明近岸台风螺旋雨带以层积混合型降水为主,台风眼墙区域以热带暖云对流型降水为主;眼墙区雨滴有效直径更大、雨滴数密度更高,有利于形成高降水强度。台风登陆前移动速度较慢,浙江沿海地区维持低层锋生和辐合,有利于外围螺旋雨带降水维持和增强;登陆前后受环境垂直切变等因素影响,台风中心左前侧眼墙区域对流活跃,在登陆点附近强降水区偏向于台风中心左侧。分钟级降水观测表明台风登陆期间浙江近海山区降水强度2~3倍于平原地区,其中地形性降水增幅效应与台风对流非对称结构差异对降水影响程度基本相当,有利于在台风中心左前侧的括苍山—雁荡山山区形成强降水中心。Extreme precipitation struck Zhejiang Province induced by Typhoon Lekima in 2019.It was found that the spiral rainbelt staggering on the coast of Zhejiang Province during the daytime of 9 August,and rainfall was enhanced significantly due to inner-core convection during Lekima’s landing period over the night.Rainfall centers were significantly related to the near-shore of Tiantai Mountain,Kuocang Mountain and Yandang Mountain in Zhejiang Province.Based on analysis of GPM(Global Precipitation Measure)retrieval cloud parameters,Lekima’s spiral rainbands were dominant by mixed cumulus-stratus precipitation,while eyewall was dominated by tropical warm cloud precipitation.With larger effective diameter of raindrops and the higher density of raindrop particles,extreme rainfall intensity was formed in Lekima’s eyewall.Spiral rainbelt was enhanced due to the low-level frontogenesis and coast convergence during the landing of Lekima.Lekima’s inner-core convection was more intense on the left direction,leading to heavier rainfall on the left side of typhoon’s landing position.By comparing precipitation rate evolution between mountainous and plain areas via statistics with minute-interval automatic weather station observation,it was preliminarily proved that the topographic rainfall enhancing mechanism and the asymmetric inner-core convective structure have almost the same impact on precipitation intensity,both favoring the asymmetrical rainfall concentrating on the left side to Lekima’s forwarding direction.

关 键 词：台风暴雨 螺旋雨带 眼墙 垂直切变 地形 

分 类 号：P447[天文地球—大气科学及气象学] P458