甘肃省一次区域性暴雨的准地转Q矢量分析

An Analysis of the Quasi-Geostrophic Q-vector of a Regional Heavy Rain in Gansu Province

运用准地转Ｑ矢量理论，对１９９８ 年７ 月４ ～６ 日甘肃省一次区域性暴雨过程进行了诊断分析。结果表明，低层Ｑ矢量散度辐合中心与暴雨区有很好的对应关系，Ｑ 矢量表示的非地转风辐合及其在等θｓｅ 线密集带两侧方向相对的特性，对暴雨有重要的指标意义。这种方法在实际预报业务中有一定的参考价值。

By means of quasi-geostrophic Q-vector theory, a regional heavy rain on 4-6 July in 1998 is diagnosed in Gansu province. The results suggest that the position of the Q-vector convergence is correlated well to the heavy rain area at lower level. The convergence of Q-vector ageostrophic wind and its opposite direction on the two sides of the concentrated contour of potential equivalent temperature is an important indicator for heavy rain. The method can provide some valuable information for local short range weather forecast.