陇东异常偏早暴雨个例分析

Exceptionally Early Heavy Rain Case Study in Eastern Gansu Province

对2003年4月1日陇东庆城县暴雨过程的环流背景、动力、热力和水汽等条件诊断分析,旨在探讨陇东春季异常偏早暴雨的短期天气分析预报思路。结果表明:异常偏早暴雨过程前48h和24h,增温明显,地面的湿静力能量跃增,后期冷空气较强,中低层对流性不稳定层结显著,深厚的正涡度、低层的低涡辐合和高空的强辐散场发展是仲春季节产生异常偏早暴雨的主要影响因子。

A diagnostic analysis was made of the circulation background, dynamical and thermal and water vapor conditions for a heavy rain event on the 1 April 2004 over the eastern Gansu Province, aiming to find out useful forecasting hints for the sort of heavy rainfall. The results show that the main influencing factors include： temperature increased obviously 48 and 24 hours before raining; surface humid-static energy increased rapidly; there existed strong cold air activity, remarkable mid- and lower-level convection, profound positive vorticity, lowerlevel low-vortex convergence, and upper-level strong divergence at the end.