双偏振雷达在地面自动雨量观测资料质量控制中的应用研究

Application Research of Dual-Polarization Radar in Quality Control of Automatic Rain Gauge

采用雨量计联合双偏振天气雷达对雨量计数据进行综合质量控制,使用反距离权重法(inverse distance weighting,IDW)从空间一致性上对自动雨量计进行质量控制,并用质量控制后的数据对双偏振雷达定量降水估测值(quantitative precipitation estimation,QPE)进行订正。利用订正后的QPE与雨量计观测值进行统计分析以确定质量控制规则,从空间及观测一致性上对自动雨量计进行综合质量控制。使用一次台风降水过程对质量控制算法的效果进行了验证,结果表明:单纯使用IDW法对雨量计进行空间一致性质量控制存在较多误判,主要是由于降水的局地突发性、结构不均匀性以及雨量计分布的稀疏性造成。结合偏振雷达,能够有效降低单纯使用空间一致性质量控制所引起的误判。经过雨量计校准订正后的QPE有了较大改善,从而提高了偏振雷达对雨量计质量控制的有效性。在台风降雨过程中,平均每小时约有5%的雨量计被认为是错误站点。综合质量控制法在雨量计分布稀疏或者处于降水边缘地带时存在一定的误判。

In this paper,the dual-polarization weather radar data are used to improve the quality of the automatic rain gauge data.The quality of the rain gauge data is improved by using the inverse distance weighting method(IDW),and the rain guage data after quality control are used to correct the rainfall data derived from dual-polarization radar.The quality control method is determined by using the revised radar-gauge data,and the quality of gauge data is comprehensively controlled from the perspective of spatial consistency and observation consistency.The comprehensive quality control method is verified by using a typhoon precipitation process.The results show that there are some misjudgments in the spatial consistency of rain gauge observations by only using IDW method,mainly due to the abruptness of local precipitation,the inhomogeneity of rainfall structure and the sparse distribution of rain gauges.The misjudgments caused by the simple use of spatial consistent property control method can be effectively reduced by combining with polarization radar.The rainfall estimations of radar have been greatly improved after the rain gauge calibration and correction so that the effectiveness of the polarization radar used in the quality control of the rain gauge is improved.During typhoon rainfall,about 5%of the rain gauges per hour are considered as the error sites with wrong results.This comprehensive quality control method has some misjudgments when the distribution of the rain gauge is sparse or when the rain gauge lies in the edge of precipitation.