多普勒雷达对华北春季强降水过程的动力学诊断

A Doppler Radar Dynamical Diagnosis of Heavy Precipitation in North China in Spring

主要应用多普勒雷达基数据资料,结合天气图实况物理量场,对2004年4月25日出现在华北区域的一次大范围较强降雨过程进行了分析。应用MGS法改进的EVAD技术,计算出垂直高度层的平均散度和平均垂直速度,初步分析了此次降水过程的动力学特征。发现由雷达数据计算出的散度和垂直速度与天气图吻合得非常好,而且降水的雨强和雷达探测范围内各高度层的辐合、辐散有比较密切的关系,这为预报降雨生消以及有效地实施人工增雨作业提供了一定的理论依据。

Performing Doppler weather radar data mainly, and associating with the weather chart fields of physical variable, a areal heavy precipitation process which occurred in North China in April 25 th, 2004 was analyzed. The average divergence and vertical velocity in each altitude layer were calculated according to EVAD method which was modified by Gram-Schmidt arithmetic（MGS）, the dynamical mechanism in the precipitation process was analyzed primarily, a very fine coincidence was discovered between the weather chart data and the divergence and vertical velocity which were calculated from radar data. Furthermore, there are quite close relation between the precipitation intensity and the convergence and divergence in layers in the range of radar exploring. This study provided some efficiently information for predicting the generating and disappearing of precipitation and artificial precipitation enhancement.