一次弱环境场下的郑州局地暴雨预报难点分析

2009年8月4日夜间,郑州市区发生了一次局地暴雨天气。此次暴雨历时短、强度大,但发生前影响系统较弱,有一定的预报难度。利用常规的高空、地面资料,卫星、雷达和自动站资料及NCEP资料对这次过程的诊断分析结果表明:这次局地暴雨没有强的水汽输送,也没有明显的辐合辐散,不属于郑州典型的强降水过程,而是具有明显的中尺度特征。郑州市低层高温、高湿积累了不稳定能量;弱冷空气的入侵及地面中气旋的生成,触发了不稳定能量的释放,从而形成这次暴雨。

Analysis of Forecast Difficulties for Local Torrential Rain in Zhengzhou Under the Weak Ambient Field

In the August 4, 2009 night, there was a local torrential rain in Zhengzhou. The duration of the rainstorm was shorter with greater intensity. But there were some forecast difficulties because of the weak influence system before the rainstorm. This paper conducted the diagnostic analysis by using NCEP data, conventional meteorological data, satellite data, radar data and automatic weather station data. The result indicated that there wasn''t strong water vapor transport and convergence or divergence movement of the local torrential rain; it didn''t belong to typical heavy precipitation in Zhengzhou. The mesoscale feature of the rainstorm is obvious. The high temperature and high moisture at low level in Zhengzhou accumulated the unstable energy; the weak cold air invasion and surface cyclone production triggered the unstable energy release. Thus form this rainstorm.