LIU Xiaobo,CHU Hai.Cause analysis of an extremely heavy rainfall event under binary typhoons pattern in Yangtze River delta [J].Torren-tial Rain and Disasters,2019,38(2):97-106莫兰蒂台风
双台风形势下长三角地区一次大暴雨过程的成因分析
，储海
（上海中心气象台，上海200030）
摘要：利用常规观测资料、多普勒天气雷达拼图资料与NECP 再分析资料，对2016年9月15—16日发生在“莫兰蒂”（1614号）和“马勒卡”（1616号）双台风形势下的长三角地区大暴雨过程的成因进行了诊断分析。结果表明：此次暴雨过程发生在台风倒槽的顶端，暴雨区与对流层中低层辐合区和中高层高空急流右后侧辐散区相对应；“莫兰蒂”台风外围的丰富水汽与来自热带洋面“马勒卡”台风外围源源不断输送的水汽叠加，导致长三角地区降雨强度远大于“莫兰蒂”登陆前后阶段的降雨强度；苏皖地区高空槽后冷空气侵入，在浙江到上海沿海地区形成东北—西南向温度锋区，以及浙江中北部海陆交界地带特殊山脉地
形的强迫作用，使得中尺度对流系统(MCSs)发展维持；长三角强暴雨区边界水汽通量收支变化与暴雨强度变化对应关系较好，且有6～12h 的提前量，对强降雨预报有一定的指示意义。
关键词：暴雨；双台风；台风倒槽；水汽输送；高空急流；中尺度对流系统
中图法分类号:P458.1+21.1文献标志码：ＡDOI :10.3969/j.issn.1004-9045.2019.02.001
收稿日期：2018-12-03；定稿日期：2019-03-19资助项目：国家自然科学基金项目(41475040)；中国气象局预报员专项(CMAYBY2017-023)
第一作者：，主要从事天气预报业务和暴雨研究。E-mail:lxb9326@sina 引言
台风暴雨是夏秋季我国东部沿海地区最主要的
灾害天气之一，其雨量集中、持续时间长，易造成山洪
地质灾害和城市内涝等次生灾害，灾害损失严重[1,2]。
近10多年来，国内针对台风暴雨特征及其形成与发展
机理等进行了大量研究，取得许多重要成果。陈联寿[3]指出，台风暴雨区大体可分两个区域，即台风
环流本身的暴雨区和台风远距离暴雨区，历史上许多大的暴雨灾害就是在台风与其北侧副热带高压形成低空偏东急流的形势下发生的。孙建华等[4]研究认为，高低空急流的相互配合对台风暴雨的产生和加强具有不
Cause analysis of an extremely heavy rainfall event under binary
typhoons pattern in Yangtze River delta
LIU Xiaobo,CHU Hai
（Shanghai Central Meteorological Observatory,Shanghai 200030)
Abstract ：Using datasets of conventional observations,the regional mosaics of Doppler weather radar and NCEP/NCAR reanalysis,we have conducted a diagnostic analysis of the cause for an extremely heavy rainfall event under binary typhoons pattern occurred in Yangtze River delta from September 15to 16in 2016.The results indicate that the heavy rainfall areas of this event locate in the top of inverted trough of the No.1614TC “Meranti”after it landed,and are corresponding with the convergence zone in the lower and middle troposphere and the diver-gence zone at the right rear side of high-level jet in the upper troposphere.The overlay of the abundant water vapor around Typho
on “Moran-ti”and the continually water vapor coming from the periphery of Typhoon “Malecas”over the tropical ocean results in the rainfall intensity in the Yangtze River Delta far greater than that before and after the landfall of Typhoon “Moranti”.A northeast-southwest temperature front zone forms along the coast of Zhejiang to Shanghai with the intrusion of cold air behind the high-altitude trough in Jiangsu and Anhui province,and a forcing effect of the special mountain terrain produces in the sea-land junction zone in the north-central part of Zhejiang province,which significantly promotes the development and maintenance of the mesoscale convective system (MCSs).The variation of water vapor flux budget in the four boundary of the heavy rainfall area in Yangtze River delta is well corresponding with to the change of heavy rainfall intensity,and the former varies 6-12hours in advance with respect to the latter,which can be an indicator for the forecast of severe precipitation.Key words ：heavy rainfall;binary typhoons;inverse trough of typhoon;water vapor transportation;upper level jet;MCSs
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