新疆昌吉州一次暴雨过程分析

Analysis of a Rainstorm Process in Changji, Xinjiang

利用常规气象观测资料、物理量场计算数据和FY-2D等资料,对2015年6月9~10日新疆昌吉州暴雨天气过程的环流形势演变特征和暴雨形成原因进行了诊断分析,研究表明:此次暴雨过程发生在南亚高压呈双体型的形势下,西西伯利亚低槽是本次暴雨的主要影响天气系统,其北段槽快速东移并向北收缩,而南段槽则在巴尔喀什湖附近向南加深发展且移速缓慢,导致北段槽后冷平流与南段槽前暖湿平流得以在天山北麓交汇,同时建立上干冷,下暖湿的大气不稳定层结;低层丰沛的水汽以两条路径输送至降水区;控制新疆大部地区的高压脊稳定少动,导致中低层辐合上升、高层辐散下沉运动持久,并在物理量假相当位温、k指数和si的最佳配置下诱发昌吉州产生暴雨天气;暴雨的对流云团产生在冷锋云系的前部,是中天山地形的辐合抬升作用所致,不断生成的对流云团合并加强,并沿昌吉州自西向东移动而形成“列车效应”,造成昌吉州出现强降水。

Based on conventional meteorological observation data, physical quantity field calculation data and FY-2D data, the evolution characteristics of circulation situation and the causes of heavy rain in Changji Prefecture of Xinjiang from 9 to 10 June 2015 were diagnosed and analyzed. Research showed that: The rainstorm happened in the double-body situation of the South Asian High. The low trough in Siberia was the main weather system affecting the heavy rain. The trough in the north section moved rapidly eastward and contracted northward, while the trough in the south section deepened southward and moved slowly near Lake Balkash, resulting in cold advection behind the trough in the North section and warm-humid in front of the trough in the South intersection. The advection could converge at the northern foot of Tianshan Mountains, and the unstable stratification of the upper dry-cold and lower warm-humid atmosphere was established;the abundant water vapor in the lower layer was transported to the precipitation area by two paths;the stable and less movement of the high-pressure ridge was controlled in most areas of Xinjiang, resulting in the rising convergence of the middle and lower layers, the sustained sinking of the upper divergence. Rainstorm weather in Changji was induced by optimum configuration of Pseudo-equivalent temperature, K index and Si of physical quantities. Rainstorm convective cloud cluster was generated in the front of cold front cloud system, which was caused by convergence and uplift of the mid-Tianshan to pography. Continuous convective cloud cluster merged and strengthened, and moved from west to east along Changji to form “train effect”, which resulted in strong precipitation of Changji.