西行热带气旋影响云南降水的统计特征  

AN ANALYSIS ON STATISTICAL CHARACTERISTICS OF WESTBOUND TROPICAL CYCLONES(TC) IMPACTING RAINFALL IN YUNNAN PLATEAU

作　　者：郭荣芬[1] 肖子牛[2] 李英[3] 

机构地区：[1]云南省气象台,云南昆明650034 [2]中国气象局气候中心,北京100081 [3]中国气象科学研究院,北京100081

出　　处：《热带气象学报》2010年第6期680-686,共7页Journal of Tropical Meteorology

基　　金：国家重点基础研究发展规划项目(2009CB421504);国家自然科学基金项目(40975032);云南省气象局预报员专项(YB200901)共同资助

摘　　要：利用《西北太平洋热带气旋年鉴检索系统》资料、NCEP/NCAR再分析资料、云南日降水资料、西北太平洋热带气旋及降水分布资料,分析了1959—2007年影响云南高原降水的西北太平洋西行热带气旋的气候特征及大尺度环流背景。结果表明:云南几乎每年都受到西行热带气旋的影响,年代际分布总体呈下降趋势,且发生在7—9月最多;热带气旋的影响波及云南大部,影响滇东南较多,以登陆的南海台风为主,其登陆地点主要为海南和广东,且多数进入北部湾;影响路径划分为5类,其中广东登陆类最多、影响最大;各种强度的热带气旋均可造成全省性强降水,其中超强台风的影响最多最大。环流背景表现为:100 hPa南亚高压呈西部型分布时,有利于西北太平洋TC西行影响低纬高原;500 hPa中纬度以纬向环流为主,低纬度热带地区季风低压、热带辐合带(ITCZ)较为活跃,当副热带高压西脊点西伸到云南东北部、或外围反气旋扩大到青藏高原、或副热带高压与青藏高压合并,均有利于TC西行深入内陆。Using data available form the ＂Yearbook of the Western North Pacific Tropical Cyclone Retrieval System,＂ the daily NCEP/NCAR reanalysis dataset and the observational daily precipitation data in Yunnan,during 1959—2007,an analysis has been made on the climatic characteristics and the corresponding large-scale circulation patterns related to the Western North Pacific westbound TCs impacting rainfall in Yunnan Plateau.Results show that the westbound TCs in the Western North Pacific have impacts on rainfall in Yunnan almost every year,and a downward trend in decadal variation.with maximum on average from July to September each year.The areas affected by typhoon cover most of Yunnan plateau with maximum in the eastern Yunnan.Such typhoons are mainly from South China Sea with landfalling points primarly in Hainan and Guangdong,and mostly entering North Bay.The tracks of these typhoons may be classified into five categories,most of which are made landfall in Guangdong with most significant impact：all categories of the tropical cyclones are able to induce province-wide heavy rainfall in Yunnan,with super typhoons bringing about heaviest and strongest rainfall.The related atmospheric circulations exhibits that the South Asia High at 100 hPa which is distributed westward is has a favorable impact on plateau in low latitudes by westward tracking of tropical cyclones in the western North Pacific.At 500 hPa,zonal circulation dominates in mid-latitudes combined with active monsoon depression and ITCZ in low latitudes.Tropicl cyclones tend to track westward to deep inland if the west point of the ridge of the subtropical high is extended to northeast of Yunnan,or its periphery anti-cyclonic circulations are expanded to Tibetan Plateau,or the subtropical high is merged with the Qinghai-Tibetan high.

关 键 词：西行热带气旋 云南降水 统计特征 环流背景 

分 类 号：P444[天文地球—大气科学及气象学]