一次区域性大暴雨过程中尺度诊断分析  

Mesoscale Diagnosis Analysis of a Regional Heavy Rain Case

作　　者：李强[1,2] 王中[1,2] 白莹莹[1,3] 杜钦 

机构地区：[1]中国气象局成都高原气象研究所,成都610071 [2]重庆市气象台,重庆401147 [3]重庆市气象科学研究所,重庆401147

出　　处：《气象科技》2011年第4期453-461,共9页Meteorological Science and Technology

基　　金：中国气象局成都高原气象研究所开放基金项目(LPM200814;LPM2009008);重庆市气象局2010科技计划项目(zl-201003)联合资助

摘　　要：利用实况降水、FY-2C资料、实时探空、NECP/NCAR再分析资料对2009年8月2—5日川渝地区大暴雨过程主要环流系统、水汽输送特征,以及湿位涡和垂直螺旋度演变特征进行了诊断分析。结果表明:此次强降水环流背景是高空槽东移,耦合了"天鹅"台风动力阻塞维持在川渝地区的西南低涡,南侵的冷空气和西南急流输送的暖湿气流交汇,形成明显的气旋性辐合,导致不断有中小尺度对流系统的生成、发展,且降水过程中一直维持较好的水汽输送条件;湿位涡对本次降水落区有较好的指示意义,由于强降水湿位涡负值中心上空的大尺度下沉气流、强上升气流的倾斜程度和最大锋生强迫区的位置和强度,强降水落区(重庆西部)位于负值中心(四川盆地)暖气流一侧;垂直螺旋度发展演变与暴雨有着密切的关系,当螺旋度等值线密集(稀疏)时,强降水发生(减弱或结束),且暴雨发生时,总是伴随着高(低)空正(负)垂直螺旋度的耦合发生。Using the data of precipitation observation,FY-2C,real-time radiosonde sounding,and NECP/NCAR reanalysis,the evolution characteristics of key circulation systems,vapor transmission characteristics,moist potential vorticity（MPV）,and vertical helicity（VH） of the regional heavy rain event in Sichuan Province and Chongqing from 2 to 5 August 2009 are analyzed diagnostically.The atmospheric circulation background of the heavy rainfall includes the eastward high trough coupled the southwestern low vortex,the dynamic blocking of Typhoon Swan maintaining over Sichuan Province and Chongqing,the southward invasion of cold air joined with the warm and wet vapor from the south-west jet,the formation of a clear cyclonic convergence,leading to the continuous generation and development of small-scale convective systems,and the favorable conditions for water vapor transport maintained in the precipitation process.The MPV was highly indicative for the area of the rainfall in the rainfall process.Due to the large-scale descending air above the negative MPV center,the tilt degree of strong updraft,and the locations and intensities of the maximum frontogenesis forcing in the heavy rainfall,the strong precipitation area（Chongqing West） was located in the warm side of the negative center（Sichuan Basin） of MPV.The VH evolution is closely related with the heavy rain.The heavy precipitation occurs（weakens or ends） when VH contours becomes dense（sparse）,and the appearance of heavy precipitation accompanies usually the upper-level（lower-level） positive（negative） VH coupling.

关 键 词：区域性暴雨 西南低涡 湿位涡 垂直螺旋度 

分 类 号：P458.121.1[天文地球—大气科学及气象学]