台风Sinlaku(2008)生成过程环境场分析  

An analysis on the formation of typhoon Sinlaku(2008)

作　　者：杨蜀都 方娟[1] 

机构地区：[1]南京大学中尺度灾害性天气教育部重点实验室大气科学学院,南京210093

出　　处：《南京大学学报（自然科学版）》2011年第6期657-669,共13页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金(40921160382;40830958);"973"项目(2009CB421502)

摘　　要：本文利用美国国家环境预报中心1°×1°逐6h分析资料和半球观测系统研究与可预报性试验-亚太地区计划获得的云图资料,从背景条件、环流演变和背景场纬向风等方面入手,对西北太平洋地区的超强台风Sinlaku(2008)的生成过程进行了详细分析,探讨了近年来人们提出的热带气旋形成的新机制———波动临界层理论在这次台风生成过程中的作用.研究结果表明Sinlaku形成前位于有利的背景场中,是一个大东风波系统里的一系列扰动经过发展演变、并最终由其中两个弱波动合并生成的.在Sinlaku形成前的两日,由于东风波扰动与季风槽的相互作用,东风波扰动附近出现了波动临界层,在这一有利于台风生成的最佳区域里("sweet spot"),Sinlaku前期扰动逐渐加强发展为热带气旋.与之相对应的是,在Sinlaku前期扰动西侧的东风波扰动虽然大部分时间都位于临界层附近,但最终并没有发展为热带气旋.这一结果表明热带东风波扰动附近临界层的出现有利于热带气旋的形成,但并不一定会导致热带气旋的形成,台风Sinlaku的形成除了与波动临界层密切相关外,其前期扰动位于大尺度背景场纬向风辐合区有利于扰动尺度收缩、波动能量积累,这也是促进台风形成的一个重要因子.Based on the reanalysis data from the National Centers for Environmental Prediction and cloud images from THORPEX-Pacific Asian Regional Campaign,the formation of super Typhoon Sinlaku(2008) over the Northwest Pacific is analyzed in detail in this work.The result reveals that Sinlaku is originated from a large easterly wave system consisting of several smaller easterly wave perturbations.As the easterly wave system propagated westwards and then interacted with the monsoon trough,the propagating speed of the easterly wave disturbances decreased and critical layers of the waves appear,which are the 'sweet spots' for tropical cyclone formation.In the area near the critical layer,two easterly wave disturbances merged and finally developed into Typhoon Sinlaku under the effect of the distinct convergence of zonal wind.However,although the easterly wave disturbance preceding the precursor of Sinlaku was situated in the critical layer in most of the time,it failed to develop into a tropical cyclone due to the lack of considerable convergence.Therefore,though the area near the critical layer is a sweet spot for tropical cyclone formation,it is not sufficient enough for tropical cyclogenesis unless it is located in the lager-scale zonal wind convergence zone,which implies that the scale contraction of the disturbances and wave energy accumulation mechanisms play a more important role in the formation of tropical cyclone.

关 键 词：台风 东风波 波动临界层 季风槽 

分 类 号：P44[天文地球—大气科学及气象学]