几种Q矢量的比较

利用 1 991 - 0 7- 0 5T2 0— 0 6T2 0一次江淮梅雨锋暴雨过程实况资料 ,结合地面降水分布 ,从定性 (矢量场 ,即 Q)、定量 (散度场 ,即 2 · Q)的角度细致、具体地比较分析了准地转 Q矢量、半地转 Q矢量、非地转 Q矢量及湿 Q矢量的诊断特性。结果表明 :半地转 Q矢量诊断能力优越于准地转 Q矢量。非地转 Q矢量、湿 Q矢量诊断能力明显优越于准地转 Q矢量、半地转 Q矢量。准地转 Q矢量诊断能力最差 ;从定性的角度分析 ,非地转 Q矢量与湿 Q矢量诊断能力相差不大。但进一步定量分析发现 ,在整个梅雨锋暴雨过程中 ,湿 Q矢量的诊断能力大于其他 Q矢量 ;70 0 h Pa高度上各 Q矢量的矢量、散度辐合区较其在 850 h Pa和 50 0 h Pa上对降水反映更好 ,尤其是70 0 h Pa湿 Q矢量散度辐合区与降水区有非常好的对应关系。

Several Q-Vector's Comparison

Employing the data of a Meiyu front rainstorm during 5-6 July,1991 in the Changjiang-Huaihe Basins,as well as the surface precipitation distribution,the diagnostic characteristics of quasi-geostropic-,semi-geostrophic-,ageostrophic- and wet-Q-vector are analysed qualitatively(vector field) and quantitatively(divergence field).Results suggest that as far as the diagnostic function of quasi-geostropic-,semi-geostrophic-,ageostrophic- and wet-Q-vector are concerned,the second is superior to the first which is the worst of all,and the third and the last are advantageous over the first and the second obviously;ageostrophic-wet-Q-vector is almost the same with the wet-Q-vector on a qualitative basis,however,on a quantitative basis,the wet-Q-vector is the best of all;the diagnostic property of various Q-vectors at 700hPa is better than those at 850hPa and 500hPa in reflecting precipitation,especially,the convergence of the wet-Q-vector at 700hPa has a good relation with precipitation distribution.