多普勒天气雷达速度PPI图散度分布信息提取

根据大面积降水回波径向速度PPI图像产品辐合辐散特征,提出采用中值滤波法来剔除噪声污染和用逐点数据对称法来削弱回波缺失和距离折叠引起的误差。在考虑了降水粒子下落速度的情况下,采用模糊定位法来提取速度图中风速性散度特征,用直方图形式表征风向性散度特征。最后通过比较分析,说明了提取方法可较好的表征PPI速度图中的散度信息,计算散度所表征的动力学特征与大面积降水过程有较好的对应关系。

Extraction of Divergence Information from Velocity PPI Charts of Doppler Weather Radar

Based on divergence characteristics in weather radar velocity PPI charts, a divergence information extracting technique is suggested. The median filtering method is used to eliminate noise contamination and one by one data symmetry technique is used to reduce the errors because of echo lacking or range folding. Considering the effect of raindrop descending speeds, fuzzy searching method is adopted for extracting wind speed determined divergence feature and histogram is used for wind direction determined divergence feature. Comparative results show that abstracting method is effective and can well display the divergence information. There is a good corresponding relationship between atmospheric dynamics features showed by the divergence and large-scale precipitation process.