2003年淮河流域梅汛期首场大暴雨成因分析

利用T2 1 3模式的物理量场和北京大学的客观分析诊断系统对 2 0 0 3年淮河流域梅汛期首场大暴雨的成因进行了天气动力学诊断分析。结果表明 :向南运动的高层偏北风急流下沉支与低空急流上升支组成低涡切变系统是主要影响天气系统 ;水汽主要来源于孟加拉湾和南海 ,但东部海区水汽输送也不可忽视。强暴雨出现在中低层辐合、高层辐散的正涡度中心下方和负涡度中心西侧 ,并与湿位涡高值中心相吻合 ,对暴雨预报有指示意义 ;低层辐合区、水汽供应和低层平流锋生的触发作用是强降水维持的主要原因

Cause Analysis of First Heavy Rain over Huaihe Valley during Meiyu Period in 2003

By using physical quantity fields of T213 and objective diagnose analysis system of Beijing University, a synoptic and dynamic analysis of the first heavy rain over Huaihe Valley during Meiyu period in 2003 is made. The low level shear system, which is composed of the southward downdraft branch of upper level northern jet and the ascend branch of low level jet, is the main synoptic system. The vapors mainly come from the Bengal Bay and the South China Sea, but the role of vapors convey from East China Waters shouldn't be ignored. The heavy rain region appears below the positive vorticity center of the mid low level convergence and upper level divergence and near the west side of negative vorticity. And the high value center of the wet potential vorticity coincides with the heavy rain region is instructive to the forecast of heavy rain. The trigger role of frontogenesis by the low level convergence region, vapor supplement and low-level advection is the main reason of the maintenance of heavy rain.