【摘要】 针对2013年8月15—16日先后在辽宁省锦州和抚顺地区发生的特大暴雨,分别以T639和NCEP预报场作为背景场,利用中尺度数值模式WRF(Weather Research and Forecasting Model)和ADAS(ARPS Data Analysis System)同化系统进行了同化多普勒雷达观测资料的试验,检验同化雷达资料和采用不同背景场对暴雨预报的影响。结果表明:(1)同化雷达资料前,使用两种背景场的预报结果对锦州的强降水均出现漏报,同化雷达资料后,均预报出了锦州黑山一带的强降水,而12~24 h预报结果中对位于抚顺地区强降水预报的改善不大,采用T639较NCEP预报作为背景场对抚顺地区强降水的预报更好;(2)ADAS同化雷达资料后对模式初始湿度场的改善较大,700 h Pa和850 h Pa比湿有明显的增量。同时,同化雷达资料后更新了模式初始场中的水物质,水物质增量位置和强降水发生位置有较好的对应关系;(3)通过分析模式预报的风场,回波和水汽通量散度发现,同化试验预报初期在锦州和阜新一带预报出了强度较强且深厚的水汽场,低层西南暖湿气流和高层西北干冷气流的配置在锦州地区水汽区域的左侧激发了强烈的上升辐合运动,而其右侧伴有强烈的辐散是导致锦州黑山强降水爆发的主要原因。更多还原

【Abstract】 To understand the improvements of two types of background filed used to weather forecasting assimilate radar observation,WRF model and ADAS are used to forecast the rainstorm that occurred at Jinzhou and Fushun of Liaoning during 15-17 August 2013,and two types of background filed include T639 and NCEP. The Result shows:(1)WRF fails to forecast the rainstorm in Jinzhou area. After assimilating radar observation with ADAS,it has been great improved in forecasting the rainstorm at the area of Jinzhou with both background fields. There is little improvement of forecast rainfall at Fushun after assimilation within 12~24 hours,and the performance of T639 is better than NCEP as background fields.(2)The initial filed of specific humidity is improved greatly after assimilating radar observation,and distinctly at 700 and 850 h Pa. Meanwhile,the water substances in initial field are updated by assimilation,and the position have good correspondence with the area of rainstorm.(3)A strong and deep moist area is forecasted at the rainfall region in both assimilation tests. A system of strong warm wet wind jet stream from southwest at lowlevel and cold dry at high level cooperation with the high moist region is the main reason leads to the occurrence of prolonged heavy precipitation ultimately,and a wind convergence in front of the moist region and a strong sinking inflowin the back of the rainfall region also forecasted with two background fields.更多还原