贵州南部两次局地大暴雨过程对比分析  

Contrast Analysis of two Local Torrential Rains in the South of Guizhou

作　　者：杨利群[1,2] 杨静 廖移山[1] 彭芳 

机构地区：[1]中国气象局武汉暴雨研究所,武汉430074 [2]贵州省气象局,贵阳550002 [3]贵州省气象台,贵阳550002

出　　处：《暴雨灾害》2010年第3期208-215,267,共9页Torrential Rain and Disasters

基　　金：国家自然科学基金(40965004);中国气象局武汉暴雨研究所开放基金项目(IHR2006K03)

摘　　要：利用自动站观测资料、探空资料及NCEP再分析资料,对2006年6月12日夜间和2008年5月27日夜间贵州南部局地大暴雨天气过程进行对比分析。结果表明,两次过程均发生在西高东低、东北低涡稳定维持的有利环流形势下,700 hPa巴塘低涡东移是造成贵州西南部强降水的主要影响系统,巴塘低涡和低空西南急流在贵州东南部维持对贵州西南部暴雨起重要作用,同时不稳定能量在贵州南部积聚为暴雨发生提供了有利条件,但相对于后一过程,前一过程在贵州水汽辐合区更大,其大雨量级以上降水范围更广;地面中尺度辐合线生成发展是两次局地大暴雨发生发展的可能触发原因,暴雨中心位于辐合线南侧暖区中;前一过程西太平洋副热带高压较强且位置偏西(西脊点到达110°E),南支槽东移有利于引导700 hPa低涡移动,弱冷空气与暖湿空气交汇形成能量锋锋生,引起低涡强烈发展、涡旋环流增强,而后一过程副高偏弱且位置偏南、偏东,500 hPa上无高原槽影响,以及地面贵州南部为低压控制且无冷空气影响,是前一过程比后一过程降水强度更大的原因。Contrast analysis of the two local torrential rain processes taking place on 12 June 2006 and 27 May 2008 respectively in the south of Guizhou was performed with the automatic observation data,sounding data and NCEP reanalysis data.The main results are as follows.The two processes occur in the circulation background of ＂higher in the east and lower in the west＂ and the maintenance of the Northeast China low vortex,and Batang vortex in 700 hPa moving eastwards is the main influence system causing severe precipitation in the west of Guizhou,and maintenance of the Batang vortex and southwest low level jet plays an important role in the formation of rain in the southwest of Guizhou.Simultaneously,the instable energy accumulating in the south of Guizhou provides a favorable condition for the formation of rain,but the former process has larger moisture convergence region in Guizhou province and the precipitation region of more than 25 mm is vaster than that of the latter process.The two local torrential rains are possibly triggered by the origination and development of the surface mesoscale convergence line,and the torrential rain centers are located in the warm region of the southern side of convergence line.In the period of former rain process the West Pacific Subtropical High is strong and its location is westering（about 110°E）,and the southern branch trough moving eastwards is propitious to lead the low vortex in 700 hPa moving,the energy frontogenesis is formed by the intersection of weak cold air and warm moist air,which causes the strong developing of low vortex and strengthening of vortex circulation.But,in the period of the latter rain process the West Pacific Subtropical High is weak and located at bias south or east,and there is not the effect of plateau trough in 500 hPa and cold air in the south of Guizhou province,which cause the precipitation intensity of the former process to be greater than that of the latter one.

关 键 词：局地暴雨 低涡 能量锋 对比分析 

分 类 号：P458.121.1[天文地球—大气科学及气象学]