基于多普勒雷达垂直风廓线产品的风暴相对螺旋度对山西暴雨的诊断

介绍了风暴相对螺旋度（SRH）的原理及基于多普勒天气雷达垂直风廓线（VWP）产品计算螺旋度的方法，探讨了不同时间分辨率对螺旋度应用效果的影响，最后重点对山西2个典型夏季暴雨个例分别做螺旋度诊断分析。结果表明：利用VWP产品计算的SRH具有较好的时间分辨率，可用于山西夏季暴雨的短时临近预报研究，相较于15min和30min，1h分辨率的螺旋度数据稳定、曲线平滑，更有利于直观分析和业务化；螺旋度强弱变化趋势与降水大小的变化趋势比较吻合，螺旋度变化一般提前于降水变化，有1—2h的提前预报量，可以作为短时（临近）预报降水开始、维持、结束的一个有效预报因子。

Diagnosis of Two Rainstorm Weather Processes in Shanxi Based on Storm Relative Helicity

In this article, the storm relative helicity（SRH） and a method of calculating SRH based on doppler radar vertical wind pro- file （VWP） had been introduced, the application effect of SRH in different time resolution had been discussed, and diagnostic analysis of two typical summer rainstorms in Shanxi had been emphasized. The main conclusions are as follows： SRH calculated by VWP had better time resolution and could be used for forecast of summer rainstorms in Shanxi. Compared with the 15 min and 30 min time scale, the helicity of one hour resolution had stable data and smooth curve and was more suitable for visual analysis and operability. The varia- tion of the helicity intensity was ：almost consistent with the rainfall, and variation of the helicity was commonly ahead of the rainfall change by one to two hours, which could be a good indicator for nowcast of the beginning, maintain, and the end of rainfall.