季风涡旋影响西北太平洋台风生成初步分析

Analysis of influence of monsoon gyres on tropical cyclogenesis over the western North Pacific

西北太平洋对流层低层大尺度低频环流季风涡旋与台风生成有密切的关系。利用时间滤波方法将季风涡旋和台风环流从逐日台风风场中分离出来,对两次季风涡旋活动个例分析发现,气旋初始扰动都首先出现在季风涡旋中心东部,一次季风涡旋活动可以伴随着一个或几个热带气旋的生成。通过进一步分析2000—2009年季风涡旋活动与热带气旋的生成关系发现,虽然季风涡旋的定义与环流强度和持续时间有关,但是热带气旋的生成位置大多数分布在季风涡旋的中心和东部,这可能与季风涡旋的Rossby波能量频散有关。

Studies have shown that large-scale monsoon gyre activity is closely associated with tropical cyclogenesis over the western North Pacific. In this study,two cases of monsoon gyre activities in 2002 and2009 were first examined. It was found that a monsoon gyre can be linked to the formation of one or more tropical cyclones,which usually occur near or to the east of the gyre center. Further analysis of the monsoon gyre activity during the period of 2000—2009 indicates that tropical cyclogenesis mainly occurs near or to the east of the gyre center,although the definition of a monsoon gyre depends on its duration and the circulation intensity. It is suggested that the tropical cyclogensis may be associated with the Rossby wave energy dispersion of monsoon gyres.