1949—2008年热带气旋在中国大陆活动的统计特征及环流背景  

CHARACTERISTICS OF TROPICAL CYCLONE ACTIVITIES OVER China's Mainland IN 1949—2008 AND ASSOCIATED BACKGROUND CIRCULATION

作　　者：魏娜[1] 李英[1] 胡姝[1,2] 

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室,北京100081 [2]海军海洋水文气象中心,北京100161

出　　处：《热带气象学报》2013年第1期17-27,共11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(40675033;40730948);中国气象科学研究院基本科研业务费专项(2007Y006)共同资助

摘　　要：利用中国气象局1949—2008年热带气旋年鉴资料,对60年来西北太平洋(包括南海)热带气旋(TC)在中国大陆的登陆活动进行统计分析,包括TC登陆的频率、位置、强度、陆上维持时间、路径、移速及消亡等。结果表明:60年间共有391个TC登陆我国大陆,最高袭击率出现在广东西南部和广西南部,江西和安徽则为袭击率较多的内陆地区。TC在大陆的年均登陆纬度为24.1°N,长期无明显变化,但1990年代至2006年间有偏北的趋势。登陆后强度衰减主要出现在前6 h,登陆24 h后各强度等级TC的衰减率趋于一致。TC陆上维持时间年均25 h,无明显年际变化,但2004—2008年普遍大于平均值。TC登陆时移速较慢,低于20 km/h,登陆后有所加快。TC平均移速在我国东北部最大,可达45 km/h以上。陆上TC最终34%重新入海,6%移至国外,60%在我国大陆消失(其中65%消失在沿海)。在此基础上,利用NCEP资料,对TC在我国大陆以不同路径活动及不同季节相似路径(北上转向)的环流背景进行合成分析对比。结果表明,西行、西北行、东北转向的TC环流背景的差别主要体现在副高形态和强度、西风槽的影响以及高空流型的差异上,其中东北转向TC与青藏高压以及西风槽的加强活动有密切联系。孟加拉湾低值系统的活动以及TC环流与西南风低空急流联结是三类TC的共同特征,说明季风活动、水汽通道的建立是TC在我国大陆活动的重要条件。不同季节相似路径TC的环流形势相似,但西风槽与TC的相互作用对TC陆上维持有不同影响。With Tropical Cyclone（TC） Yearbooks data from 1949 to 2008, statistical analyses are performed to s^dy the climatic features of TCs which made landfall in the mainland of China, including its landfalling freqdency, spots, intensity as well as track, moving speed, sustention and dissipation etc. Results indicate that there are 542 TCs made landfall in China and about 71% of the total attacked the mainland during the past 60 years. Regions most frequently affected by TCs are the southwest of Guangdong and south of Guangxi, while Jiangxi and Anhui are the inland areas with highest frequency. The annual average landfalling latitude is 24.1 °N, with northern tendency after the 1990s till 2006. TCs with different intensity weaken significantly in the first 6 hours post landfall, but the decay ratios become consistent after 24 hours. In addition, there is no obvious interannual variability of TCs＇ durations over land. However, from 2004 to 2008, TCs sustained longer over land than the normal （25 hours）. Generally, TCs move more slowly when making landfall, less than 20 kin/h, but accelerate after landfall. And they have the fastest moving speed over the northeast of China, exceeding 45 km/h. Finally, 34% of mainland landfalling TCs re-enter the sea, 6% enter other countries and 60% disappear in the mainland with 65% hereinto dissipate along the coast. In addition, with the NCEP reanalysis data, composite analyses are carried out to study the large-scale circulation for TCs with three different tracks respectively： westward, northwestward and recurvature. The main differences are associated with the pattern of the western North Pacific subtropical high, westerly trough, and upper-level flows. TCs with recurving tracks are related closely to the development of Tibetan High and westerly trough at mid-latitude. A common feature for all TCs is that there are vortices over the Bay of Bengal and southwest low-level jet stream coupled with TC circulation, indicating that monsoon activities and water vapor transport

关 键 词：热带气旋 气候特征 环流背景 中国大陆 

分 类 号：P444[天文地球—大气科学及气象学]