浙江省热带气旋倒槽暴雨气候特征研究

基于近40年热带气旋（Tropical Cyclone，简称TC）日降水和最佳路径等观测资料，采用数理统计、天气学分析等方法对浙江省TC倒槽暴雨分布特征及其与TC的相互关系进行研究。（1）浙江省年均会发生1.8次TC倒槽暴雨，占TC暴雨总数约4成，是浙江省台风暴雨中的一种重要形式。每年8—9月是TC倒槽暴雨高发期，暴雨主要发生在宁波南部至温州一带沿海地区，暴雨中心多位于台州和温州沿海。（2）引发浙江省TC倒槽暴雨的热带气旋多在粤东至浙南登陆之后北上转向或西北行，登陆当天最易发生暴雨且雨强最强。暴雨发生时，福建中部沿海经海峡至台湾东北部一带是TC高频活动区。（3）距TC中心2.5~5.0纬距之间和TC东北偏北象限是倒槽暴雨中心的高频落区；较强暴雨发生在TC强度为热带低压时，且强中心易位于TC东北偏东象限，极端强降水发生主要与热带低压和副高等相互作用形成的偏东暖湿急流、TC倒槽强辐合和TC东北偏东象限中尺度深对流系统频繁活动有关。 

CLIMATIC CHARACTERISTICS OF RAINSTORM ASSOCIATED WITH INVERTED TROUGH OF TROPICAL CYCLONE IN ZHEJIANG PROVINCE

Based on the past 40 years of daily rainfall data of tropical cyclones and their best track observations from Shanghai Institute of Typhoon of China Meteorological Administration (CMA), climatic characteristics of rainstorms associated with inverted troughs of tropical cyclones (for brief, called RIT below) in Zhejiang province are investigated in this paper by statistical and weather analysis methods. Results are showed as follows: (1) On average, there are 1.8 times of RIT each year, which account for 41% of total tropical cyclone rainstorm frequency and thus RIT is an important form of tropical cyclone rainstorm in Zhejiang province. Most of RIT happens from August to September and in coastal areas from the southern Ningbo city to Wenzhou city. Moreover, strong precipitation centers are usually located in coastal regions from Taizhou city to Wenzhou city; (2) Tropical cyclones which induce RIT mostly make landfall on the coastal regions from the eastern Guangdong province to the southern Zhejiang province, with northward then recurvature tracks or northwestward tracks over land. On the days of landfall, the RIT most likely occurs and has the strongest rainfall intensity. During the burst period of RIT, tropical cyclones are usually in the region from the coast of middle Fujian province via Taiwan Strait to northeast Taiwan Island; (3) The asymmetric distribution of maximum RIT relative to tropical cyclones is prominent, with high probability in the regions of north-northeast azimuth and the ring between 2.5 and 5.0 degrees of zonal distance from the tropical cyclone center. However, the maximum of RIT intensity appears in tropical depressions and is often located in the east-northeast azimuth. The extreme precipitation events mainly relate with the interaction between tropical cyclones and periphery systems such as western north Pacific subtropical highs, resultant easterly jets and strong convergence near the tropical cyclone inverted troughs, as well as active mesoscale deep convection in the east-northeast azimuth of tropical cyclones.