台湾岛及邻近区域热带气旋异常路径特征分析

A Statistical Analysis of Unusual Track Characteristics of Tropical Cyclones Passed or Close to Taiwan

利用热带气旋资料和天气图、卫星云图等观测资料,统计分析了1949-2008年入侵台湾岛及邻近区域的热带气旋出现的各类异常路径的时间、空间分布规律及成因。结果表明,异常路径的形成是环境流场和台湾地形共同作用的结果,在特定的环流形势下,台湾地形的影响,导致入侵这一带区域的热带气旋结构及其周围的气压场和流场发生变化,并可能诱生出地形槽或低压。热带气旋出现左折、右折、打转和诱生低压发展取代原热带气旋的异常路径,发生在不同地点的异常路径,地形和环境作用的主次关系不同。

A statistical analysis of the causes,the spatial and temporal distribution characteristics for unusual tracks of tropical cyclones（TC） passed or close to Taiwan is performed,from 1949 to 2008,using tropical cyclone data and observational data,such as synoptic chart,satellite cloud picture and so on.The result reveals that the consociation of ambient fields and the Taiwan topographic forcing results in unusual tracks.In specific ambient fields,the Taiwan topographic forcing leads to changes in the structure of TC entering into this area,as well as the fields of pressure and wind around,and probably causes induced topographic trough or depression.The topographic forcing and the ambient fields play different roles in the unusual track,primary or secondary,when the TCs turn left,turn right,loop or are replaced by the induced depression,while the abnormality occurs in different regions.