“8.19”华北区域暴雨的数值模拟与诊断分析  

Numerical Simulation and Diagnostic Analysis About a Heavy Rainstorm Process in North China Based on WRF Model

作　　者：马严枝[1] 赵桂香[1] 郝婧宇[1] 闫慧[1] 张磊[1] 

机构地区：[1]山西省气象台,山西太原030006

出　　处：《干旱气象》2016年第3期511-521,共11页Journal of Arid Meteorology

基　　金：国家自然科学基金项目"黄河中游地区突发性大暴雨MCC结构特征研究"(41475050)资助

摘　　要：利用中尺度数值预报模式WRF3.2和NCEP 1°×1°再分析资料,对2010年8月18—19日发生在华北地区的暴雨天气过程进行了数值模拟,基于模拟结果,着重分析产生此次暴雨的动力、热力条件以及中尺度天气系统之间的相互作用。结果表明,此次暴雨过程是在有利的高、中、低层系统配置下,由高空冷涡带动干冷空气南下,与副热带高压外围的暖湿气流在华北地区上空交汇而形成;高低空急流的适宜配置,产生了动力场的耦合作用,形成深厚、强烈的上升运动,是大暴雨发生发展的主要动力条件;低空急流是主要的水汽输送通道,水汽主要来自南海和孟加拉湾;暴雨强盛时期,650h Pa以下大气表现为对流不稳定,此时华北地区上空的K指数>35℃,强降水时段出现在K指数梯度明显增大的过程中;对流层高层的干冷空气不断侵入触发对流层低层不稳定能量释放,强降水发生在低层暖平流向上抬升、高空冷平流向下侵入的时段。A heavy rainstorm occurring in North China during 18 - 19 August 2010 was simulated by using WRF＇3.2 （ Weather Research and Forecasting Model for version 3.2） and NCEP reanalyzed meteorological data with 1°×1° grid. Based on reasonable simulation results, the dynamical, thermal mechanism of the heavy rain formation and the interaction of the mcsoscale weather systems were analyzed. Results show that under the beneficial circumstance of the high, medium and low system configuration, the northern cold air driven by high altitude vortex met with warm wet air from the edge of the subtropical high in North China, which provided the favorable weather conditions for the heavy rain. The strong rainfall took place on the left front side of the low jet, and the low jet played an important role in this case. The strengthening of a high - level jet stream and its momentum downward spreading made the maintenance of the low level jet, and the coupling of the high and low - level jets provided a proper dynamical condition for the occurrence and devel- opment of the torrential rain process. The atmospheric air presented convective instability below 650 hPa during the period of heavy rainfall, at the same time the K index was more than 35 ℃ in North China, strong precipitation appeared in the process of K index gradient increasing significantly. The cold air from upper troposphere invasion in the middle and lower layer was one of the reason causing the strong precipitation, and the strong precipitation occurred when the low- level warm advection was upward and upper -level cold advection was downward.

关 键 词：华北暴雨 数值模拟 急流 干侵入 动力场耦合 

分 类 号：P458[天文地球—大气科学及气象学]