摘要
利用常规观测、红外云图、T639资料和区域自动站资料，对2014年4月15~16日发生在河西走廊东部罕见春季暴雨的成因进行分析。结果表明，500 hPa天气系统为此次暴雨的主要影响系统。500 hPa东移短波槽是这次暴雨天气的触发系统，700 hPa偏南暖湿气流在低涡作用下不断向北输送水汽，为降水的维持提供了源源不断的水汽条件，下游高压脊的阻挡作用使降水持续时间较长；强水汽辐合、强上升运动出现时间比降水集中时间滞后3~4 h；K指数大值区、θse高能舌区与暴雨落区相符合；强冷空气的入侵，是降水量级增大的直接原因；变温对春季强降水的反应比变压更敏感；过程前期的高温高湿对降水的预报有一定的指示意义；锋前中尺度对流云团和锋面云带的合并是造成此次暴雨的直接原因。
Based on the conventional observation data,infrared cloud images,T639 data and regional automatic station data,the causes of a rare in spring in Eastern Hexi Corridor from 15 to 16 on April 2014 were analyzed. The results showed that the weather systems on 500 hPa were main influence systems of the rainstorm. The short wave trough on 500 hPa moving eastward triggered the rainstorm,the southwest jet in front of Plateau trough provided incessant and enough vapor for the rainstorm,and the precipitation lasted for a longer time combined with the blocking of the upstream high pressure ridge. The strong vapor convergence and upward motion appeared about 3-4 hours later than the concentrative precipitation. The high value areas of K index and the high energy tongue areas ofθse were coin-cided with the rainstorm area. The intrusion of strong cold air was the direct cause of precipitation increasing. The response of tempera-ture to spring strong precipitation was more sensitive than air pressure. High temperature and high humidity in earlier stage of precipita-tion could afford some indication significance to precipitation forecast. The superposition between prefrontal mesoscale convective cloud cluster and frontal cloud band was the direct cause of the heavy rain.
出处
《干旱气象》
2015年第4期651-658,共8页
Journal of Arid Meteorology
基金
2014年中国气象局气象关键技术集成与应用面上项目"甘肃斜压锋生类强降水预报技术及应用(CMAGJ2014M54)"资助
关键词
强降水
古浪
冷锋
上升运动
strong precipitation
Gulang
cold front
ascending motion
