一次暴雨空报的诊断分析  

Diagnostic Analysis of a False Heavy Rain Prediction

作　　者：施望芝[1] 祁东平 王丽[1] 高琦[1] 张萍萍[1] 

机构地区：[1]武汉中心气象台,武汉430074 [2]宜昌市气象局

出　　处：《气象》2007年第5期56-61,共6页Meteorological Monthly

基　　金：湖北省气象局气象科技基金课题;湖北省本地预报方法及应用系统研究

摘　　要：实时天气系统的时空分布、多个物理要素、雷达回波特征都表现出24小时内鄂东地区及武汉单站有暴雨天气发生,结果暴雨空报。为了找到暴雨空报原因,对T213数值预报产品中多个物理要素进行诊断分析。首先根据物理量场分析鄂东地区暴雨是否产生;其次根椐物理量值分析武汉单站有否暴雨。结果表明:鄂东及武汉单站多个物理要素场和值不支持有暴雨产生。如:没有能量锋区、湿度锋区和水汽的辐合支持降水天气系统继续发展和加强,鄂东不会产生区域性暴雨。武汉单站涡度平流反映出低层正值高层负值,这种配置没有动力作用。垂直速度表明在汉口上空整层为下沉气流区,产生不了动力不稳定。单站ra和rf值表现出,前者为正值的水汽辐散;后者为小值。K指数不但没有达到K≥35℃以上,而且表现出逐日递减。这几种要素值都不支持单站次级环流的产生,所以,武汉不会发生暴雨。The temporal, and spatial distribution of the real time synoptic systems, the physics factors and the radar echo characteristics all indicated that a heavy rain process will occur in Wuhan single-station and eastern Hubei province in 24 hours, but it is proved a false prediction. In order to find the reasons, some physics factors are diagnosed by using T213 numerical prediction products. Based on the physical variables, an analysis whether the heavy rain will occur in Wuhan single-station, and even in eastern Hubei Province is made. The results show that many physical factors did not consist with the forecast that a heavy rain process will occur in the eastern Hubei province and Wuhan single-station. For example, without the energy front zone, the moisture front zone and the moisture convergence, the rainfall synoptic system won＇t develop and intense.Thus the regional heavy rain won＇ t occur. The vorticity advection of Wuhan single-station appears posirive value at low level and negative value at high level. Such configurations have no dynamic effects. Vertical speed indicates that there are downdraft at the whole upper layer of the single-satation. All these positions cannot offer the important conditions for dynamic instability. Ra shows that moisture flux divergences are strong at upper troposphere of Wuhan single-station and rf is in a low value. K index does not reach at 35℃ but decrease day by day. Those physics values cannnot trigger secondary circulation of single- station. So no heavy rains occur in Wuhan.

关 键 词：暴雨 落区 单站 空报 诊断分析 

分 类 号：P458.121.1[天文地球—大气科学及气象学]