河南省2011年8月1-2日暴雨过程水汽条件与垂直螺旋度分析  

Analysis of the Water Vapor Condition and Vertical Helicity on the Torrential Rain in 1-2,August 2011 in Henan

作　　者：喻谦花 姜东东 康暑雨 

机构地区：[1]开封市气象局,河南开封475004

出　　处：《气象与环境科学》2012年第2期56-60,共5页Meteorological and Environmental Sciences

基　　金：河南省气象局气象科学技术研究项目(Z201213)资助

摘　　要：利用常规资料和NCEP再分析资料,对2011年8月1-2日河南省区域性暴雨过程的环流形势、水汽条件和垂直螺旋度进行了分析,结果发现:这次暴雨是一次较为典型的西南涡东北移影响河南所造成的暴雨过程,500hPa高原槽东移,副热带高压减退之后又增强,中低层西南涡沿切变线东北移出,河南处于涡前的西南低空急流出口区前方及前方左侧,具备了区域性暴雨产生的动力与水汽条件。在本次暴雨过程中,700 hPa水汽通量变化对强降水落区有很好的指示作用:豫西南的暴雨区位于水汽通量大值中心附近和前端水汽通量等值线密集带内,豫中东部的暴雨区位于水汽通量大值中心北部水汽通量等值线密集带内、大值中心运动方向的左侧。水汽通量散度场上,850 hPa水汽通量散度的变化与暴雨的开始时段和强度有很好的对应:水汽通量散度转为辐合、辐合层增厚为强降水开始的标志,辐合量突然增大标志着降水强度增大。700 hPa垂直螺旋度的迅速增强与强降水发生时段有较好的对应,强降水产生在垂直螺旋度大值轴的东南侧。Using the conventional data and NCEP reanalysis data in Henan on 1--2, August 2011, the paper analyzed the circulation situation, water vapor condition and vertical helicity of the torrential rain. The results showed that： the moving to the northeast nearly to Henan by the southwest vortex is the typical effects. The plateau trough at 500 hPa moves toward to the east, subtropical anticyclone becomes weaker and then stronger, the southwest vortex in the middle-low level moves along with shear line to the northeast. Henan lies in the front and the front left side of southwest low-level jet export, which provide an advantageous dynamic and water vapor condition to the torrential rain event. The water vapor transport at 700 hPa has a very important indication in this rainfall area. The torrential area in southwestern Henan is near the maximal value of vapor flux and in the front of density gradient with it. The torrential area in central and eastern Henan is in the north of density gradient with vapor flux and the left of the direction of its maximal value＇ s movement. The change of vapor flux divergence at 850 hPa and the begin and strength of the rain have more correlation. The vapor flux divergence turns to convergence, and the convergence layer becomes heavy is the symbol of starting of torrential rain, the sudden enlargement of vapor flux divergence meaning the enlargement of the Strength of the rain. The rapidly increasing of vertical helicity at 700 hPa is corresponded to the rain happen time ; the heavy precipitation occurred in the southeast of the vertical helicity maximal value axis.

关 键 词：暴雨 西南涡 水汽条件 垂直螺旋度 

分 类 号：P458.121.1[天文地球—大气科学及气象学]