基于数字高程模型和反射率因子垂直廓线的天气雷达波束遮挡订正算法

Weather Radar Beam Block Correction Algorithm based on DEM Model and Vertical Profile of Reflectivity

天气雷达在部署时如果周围存在山体,雷达波束将会在山体附近受到部分遮挡甚至是完全遮挡,会对雷达探测范围和雷达数据的准确性产生较大影响。为解决波束遮挡问题,使用北京地区的SRTM数字高程数据,模拟位于北京房山的X波段双偏振雷达的波束遮挡情况,计算雷达体扫各层的波束遮挡率并与雷达反射率图片进行对比以验证其可行性。依据波束遮挡率,选取根据非遮挡区域的反射率因子计算的平均垂直廓线对雷达的部分波束遮挡区域的反射率因子进行订正,并通过定量分析对平均垂直廓线法进行订正效果分析。结果表明:数字高程模型模拟的波束遮挡率能较好地代表雷达的波束遮挡情况,平均垂直廓线法能够较好地订正天气雷达的波束阻挡区域的反射率,但其订正效果容易受到生成廓线区域选择的影响。

When the weather radar is located near a tall mountain,the radar beam can be partially or even completely blocked near the mountain,which will have a great impact on the radar detection range and the accuracy of radar data.In this paper,the SRTM digital elevation data of Beijing area is used to calculate and analyze the beam blocking fraction of the X-band dual-polarization radar located in Fangshan,Beijing.And according to the beam occlusion rate,the vertical profile of reflectivityis used to correct the reflectivity dataofpartially beam block area,and the correction effect of the average vertical profile method is analyzed by quantitative analysis.The results show that the mean vertical profile method can better correct the reflectivity of the beam blocking area of the weather radar,but its effect can be easily affected by the selection of area which is used to generate profile.