热带气旋登陆维持和迅速消亡的诊断研究  

Diagnostic Study of the Sustaining and Decaying of Tropical Cyclones after Landfall

作　　者：李英[1] 陈联寿[1] 王继志[1] 

机构地区：[1]中国气象科学研究院,北京100081

出　　处：《大气科学》2005年第3期482-490,共9页Chinese Journal of Atmospheric Sciences

基　　金：国家科技部973项目2004CB418300;国家自然科学基金项目40175019

摘　　要：采用动态合成方法,对登陆后长久维持热带气旋(LTC)和迅速衰亡热带气旋(STC)的涡度、动能、热量和水汽的收支平衡进行计算和对比分析。结果表明:(1)LTC在陆上长久维持过程中,其低层正涡度衰减缓慢并保持一定强度。STC登陆后正涡度减弱较快。(2)热带气旋登陆后涡度的收支主要取决于水平散度项、平流项和剩余项。散度项使LTC低层正涡度增加,高层减少,平流项和剩余项则使其低层涡度减弱,高层涡度增加。总体而言,LTC自高层获得正涡度的补充,STC则没有获得环境正涡度。(3)低层,摩擦耗散使LTC动能减少,但动能通量辐合可补充部分动能而减缓衰减。中高层,LTC登陆后36～60h动能收大于支,动能的增加一部分来自于斜压动能制造,一部分来自于次网格尺度。STC有类似的动能耗散,却无动能补充。(4)LTC登陆后保持一定强度,并从外界获得热量和水汽补充来支持积云对流发展,而积云对流对LTC的维持具有正反馈作用。STC登陆后没有这一过程。Based on dynamic composite analysis, the vorticity, kinetic energy, heat and moisture budgets are calculated for two categories of typhoons, one quickly dissipates right after it touches the ground surface (024 hours, hereafter referred to as STC) while the other sustains over land for a long period after its landfall (35 days, hereafter referred to as LTC). The results have shown that (1) LTC would keep its positive vorticity a stronger value in lower level and decay slowly while STC would decrease quickly after landfall.(2) The divergence term, the horizontal advection term and the residual term of the volticity equation play an important role in the sustention of the landfalling tropical cyclone. For LTC, the first term possesses positive contribution to vorticity in lower layer and negative one in upper level, and the reversal is true for the other terms. As a whole, LTC gets positive vorticity from upper level while STC cannot gain positive vorticity from the environment.(3) In lower layers, kinetic energy increases for LTC due to the convergence of kinetic energy flux that would compensate friction consuming partly. In upper level, LTC draws kinetic energy during 3660 h after landfall due to baroclinic and subgrid scale kinetic energy generation. STC’ kinetic energy is only dissipated without compensation.(4) LTC would draw heat and vapor from outside of the cyclone that would help LTC to develop cumulus convection in its circulation. At the same time, the cumulus convective activities have positive feedback on LTC’s sustaining.

关 键 词：动态合成方法 LTC STC 涡度 动能 热量 水汽 登陆后长久维持热带气旋 迅速衰亡热带气旋 

分 类 号：P444[天文地球—大气科学及气象学]