黔东南两次冷锋低槽型降水对比分析

利用常规气象观测资料,分析对比2016年8月31日—9月1日与9月9—10日黔东南地区出现的一般性降雨和区域性暴雨天气过程。探讨两次过程降雨发生发展的天气学条件差异。结果表明:两次降水过程均属于冷锋低槽型降水,降水发生前,黔东南受热低压控制,以晴好天气为主,冷空气都是从西北路径入侵,锋面过境时地面辐合线触发降水的发生发展,降水带主要发生在中低层切变线附近,850 h Pa风速有所加强,但未达到急流强度,对降雨的强度有一定的制约。两次过程都存在降水范围大、时间长的特点。所不同的是:降水强度前者弱,后者强,两次降雨过程中低层影响的天气系统存在不同,8月31日降雨的低层影响系统为贵州西南部发展的低涡系统,黔东南上空850 h Pa形势场出现弱的辐合区;9月9日降雨的低层影响系统为明显的辐合性切变线,存在多个呈东北—西南向的以带状分布的对流系统。通过对两次冷锋低槽型降水讨论得出,黔东南冷锋低槽型暴雨预报应着眼于影响贵州的强涡度中心的建立和加强以及其移动路径。

Contrastive analysis of two Cold - Fronts and Low - Trough precipitation in southeast Guizhou

Based on the conventional meteorological observation data, the general rainfall and regional rainstorm process were compared and analyzed from August 31 to September 1, 2016, September 9 to September 10, To explore the differences in the development of the two processes during the occurrence and development of rainfall. The results show that the two precipitation processes belong to the cold front and low trough precipitation. Before the precipitation, the hot and cold pressure control in the southeast of Guizhou is dominated by fine weather, and the cold air is invaded from the northwest route. The precipitation occurred mainly in the middle and lower shear lines, 850hPa wind speed has been strengthened, but did not reach the rapids intensity, the intensity of the rainfall have some constraints. The two processes have the characteristics of large precipitation range, long time and strength. The low-level impact system is the low-vortex system developed in the southwestern part of Guizhou, and the 850hpa potential field is located in the southwest of Guizhou. 9.9 Rainfall The low-level influence system is an obvious convergent shear line, and there are many convective systems with zonal distribution in northeast to southwest. Based on the discussion of two cold front troughs, the cold trough and low trough rainfall forecast in the southeastern Guizhou should focus on the establishment and strengthening of the strong vorticity center in Guizhou and its moving path.