一次异常路径持续强降水中尺度对流系统分析  

Analysis on Unusual Path Associated with Mesoscale Convective System in a Continuous Heavy Rain

作　　者：郭大梅[1] 刘勇[1] 马晓华[1] 李萍云[1] 

机构地区：[1]陕西省气象台,西安710015

出　　处：《高原气象》2015年第6期1648-1657,共10页Plateau Meteorology

基　　金：陕西省气象局预报员专项(2015Y-4)

摘　　要：利用实况观测、NCEP、卫星云图FY-2E和自动气象站资料对一次从华北到西北地区东部持续强对流暴雨天气进行了分析,结果表明:500 h Pa东北冷涡底部的短波槽、大陆高压东侧的东北风、低层切变线及冷平流、地面冷高压底部的冷空气为中尺度系统的产生、发展、移动提供了有利的天气背景;强对流暴雨天气是由β中尺度、α中尺度对流系统造成的,中尺度对流系统大致是由东北向西南方向移动,历时23 h。东路冷空气与华北暖湿气流交汇,触发对流产生;MCS的移动方向取决于高低空的风向、风速。当中高层风速较弱、低层风速较强、风向相反时,MCS移动路径与低层风向一致;当中高层风速较强、低层风速较弱、风向相反时,MCS移动路径与中高层风向一致。强对流暴雨过程发生前,整层温度平流为零,中高层的风较弱,风垂直切变较小。By using observation data,NCEP / NCAR reanalysis data,FY- 2E product and the automatic station data,a continued strong convection rainstorm in North China to the eastern region of Northwest China is analyzed. The obtained result are as follows. Firstly,500 h Pa short wave trough which locates in the bottom of the northeast cold vortex,the northeast wind on the east side of the continent high,shear line and cold temperature advection in lower levels and the cold air in surface provide favorable synoptic background for the mesoscale convective system 's occurrence,development and movement. Secondly,meso- β scale and meso- α scale convective systems cause the strong convection rainstorm. With 23 h,mesoscale convective systems move roughly from southwest to northeast. Interaction between cold air from the eastern area and warm moisture in North China,convection has triggered. Thirdly,the moving direction of MCS depends on wind direction and speed in the whole layer. When there is the weak wind speed on high layer and middle layer and opposite strong wind speed on lowlayer,the mesoscale convective system 's moving path is consist with wind direction on lowlayer. When there is the weak wind speed on lowlayer and opposite strong wind on high and middle layers,strong wind speed on high and middle layers,the mesoscale convective system 's moving path is consist with wind direction on high and middle layers. Fourthly,the all layers are no temperature advection before the convective precipitation occurs. At the same time,the high and middle layers wind is very weak,and the vertical wind shear is very small.

关 键 词：中尺度对流系统 异常路径 高低空的风向风速 温度平流 概念模型 

分 类 号：P458.121.1[天文地球—大气科学及气象学]