摘要
选取登陆北上在辽东半岛地区形成大暴雨的9216号(Polly)台风为例,采用NCEP全球分析资料,利用MM5中尺度非静力模式,对其环境流场和影响期间冷空气的作用进行诊断分析,并对下垫面海温对Polly的强度、路径、低层辐合和水汽通量及降水的影响进行数值模拟,结果表明,Polly影响期间,稳定在125°E附近的副热带高压使低值系统偏北移动,并靠近中纬度斜压锋区,使低值系统得到发展的同时并阻挡着其东移出海;高空辐散、低层辐合相叠置,高空急流在35°N以北,呈非纬向,有利于垂直上升运动的加强和Polly的向北移动;辽东半岛地区为低空急流水汽输送辐合区;登路北上过程中,中纬度斜压锋区穿过Polly,使其获得斜压能量变性发展为温带气旋;黄海北部海面表层温度升高使热带气旋移动路径向海温暖舌区域偏折,低层辐合和水汽输送明显加强,降水量显著增加。
Choosing typhoon Polly （9216） which moved northward after its landfall and induced heavy downpour in the Liaodong Peninsula, the authors carry out the diagnostic analyses on the environmental fields and the role of cold air in the occurrence using the NCEP global analysis data and the non-hydrostatic version of the mesoscale model MMS. Furthermore, the numerical simulations are conducted to investigate the effect of sea surface temperature （SST） on the track, intensity, lower layer convergence and moisture flux as well as precipitation of typhoon Polly. The results indicate that the steady subtropical high about 125°E results in that typhoon Polly moves northward and approaches a baroclinic frontal zone, thus fails to move eastward into sea while it is reinvigorated. Superposition between the upper layer divergence and the lower layer convergence, and the non-zonal upper level jet located to the north of 35°N are favorable for intensification of upward movement in vertical and northward tracking of typhoon Polly. During typhoon Polly passing through the Liaodong Peninsula where there exists a convergence moisture transported by lower level jet, the baroclinic frontal zone in middle latitudes traverses typhoon Polly, and energizes it by way of baroclinic energy, and finally makes it develop into an extratropical cyclone. Increase of SST in the north of the Yellow Sea drives the tropical cyclone tracking towards or deflecting to a warm SST area, and leads to significant intensification of lower layer convergence and moisture transport, and therefore notable enhancement of precipitation.
出处
《大气科学》
CSCD
北大核心
2007年第5期1011-1020,共10页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础研究发展规划项目2004CB418301
国家自然科学基金资助项目40575018
关键词
黄海北部
热带气旋暴雨
大尺度环流
海温作用
northern Yellow Sea, tropical cyclone torrential rain, large scale circulation, effect of sea surface temperature
作者简介
梁军，女，1967年出生，高级工程师，主要从事短期天气预报工作。E-mail：qinldj@163．com
