1998年武汉大暴雨过程的切变涡度及非绝热加热垂直结构分析

RESEARCH ON VERTICAL SECTION OF SHEAR VORTICITY AND DIABATIC HEATING WITH WUHAN TORRENTIAL RAIN IN 1998

中文关键词:  纬向切变涡度  视热源  水汽汇  武汉大暴雨

英文关键词:Zonal shear vorticity,Apparentheat source,Moist sink,Wuhan torrential rain

中文摘要:

      文中通过比较1998年武汉大暴雨期间相对涡度、切变涡度和纬向切变涡度(ζ_s1),发现ζ_s1中心与暴雨中心位置有更好的对应关系,其在时序上高空负纬向切变涡度发展要超前强降水出现约1d。暴雨发生前高空反气旋性涡度增强,且与此同时,低层要求有正涡度发展。暴雨发生时段对应着Q₁,Q₂的高值区,并具有强上升运动,且Q₁,Q₂两者之间存在较强的耦合。视热源中心在450hPa,而水汽汇中心主要在600hPa附近。Q₁,Q₂局地变化和平流变化是反位相分布的,共同的作用是减小对加热的贡献。Q₁中局地变化可省略,但Q₂中局地变化在第2次强降水时段可达4K/d左右,因此不能省略。垂直输送项在Q₁,Q₂中是最主要的加热项。

英文摘要:

      Comparing the different vorticity components on Wuhan to rrential rain in 1998,the results show that zonal shear vorticity has a corresponding connection with heavy rainfall center while the upper-negative shear vorticity develops and the low-positive vorticity increases.Analysis of case and statistics present that the develo pment of zonal shear vorticity over 200hPa is one day ahead of heavy rainfall occur rence.Meantime,the high apparentheat source(Q₁)and moist sink(Q₂)as well as strong ascending motiongo with torrential rainstage.The source center is located at 450hPa,and the sink center at 600hP a.Evidences suggest that the transportation term plays an import ant role in at mospheric diabatic heating processes.However,the local variation ter missmall and reverse to advection term in apparentheat source ver tical section,so it is of tenignored,butit cannot be neglected in moist sink.