水平距离和海拔高度对雷达估测降水影响及订正

Influence of Horizontal Distance and Altitude on Radar Rainfall Estimation and Its Correction

以石家庄2006—2008年77次降水过程为例,分析了海拔高度和距雷达站水平距离对定量估测降水的影响,给出了估测降水时反射率因子取值的最佳高度以及距离高度订正值。对比了经验公式法和最优化法分别在有无距离高度订正4种情况下的估测效果,依据估测效果,设计了雷达定量估测降水最佳方案:若反射率因子小于30 dBz,则不进行距离高度订正,仅采用最优化法估测降水;若反射率因子大于30 dBz,则首先对反射率因子进行距离高度订正,然后采用最优化法估测降水。实例检验表明,该方案对单站10 mm·h^(-1)以上的强降水、过程降水量和区域降水量估测效果较好。

Based on 77 rainfall processes in Shijiazhuang from 2006 to 2008, this paper analyzes how quanti- tative precipitation estimation （QPE） is influenced by the altitude and horizontal distance from radar sta tions. Meanwhile, the optimum height of refleetivity factor for radar QPE and the values of distance and height corrections are suggested. The effect of QPE using the empirical formula and the optimization meth- od are contrasted with and without distance and height corrections in four situations, and a QPE optimum scheme is designed according to the comparison results. No correction hut only optimization method is adopted when the reflectivity is less than 30 dBz. Otherwise, distance and height corrections are performed firstly, and then optimization method is used in QPE. The results show that the proposed scheme has a good effect on heavy precipitation exceeding 10 mm · h^-1 at single station, and on the process rainfall as well as on the estimation of regional precipitation.