双偏振天气雷达旋转关节对差分反射率因子测量结果的影响

Effect of Rotary Joints of Dual-Polarization Weather Radar on Z_(dr) Measurements

旋转关节的质量在很大程度上影响了双偏振天气雷达双通道信号的一致性,由于现实生产工艺中旋转关节在结构上的不对称,造成双偏振天气雷达差分反射率因子(Z_(dr))的系统偏差随方位角和俯仰角发生变化,极大地影响了利用雷达数据进行定量估测降水及相态识别的精度。文章利用南京信息工程大学C波段双偏振天气雷达机内信号源的连续波输出对该雷达的方位旋转关节和俯仰旋转关节造成的Z_(dr)测量误差进行了检测,结果表明旋转关节对双偏振天气雷达Z_(dr)的测量结果有一定的影响,综合VCP扫描模式及RHI扫描模式的结果得出旋转关节造成的影响较为稳定,为进一步利用雷达数据进行旋转关节误差订正提供了一定理论支撑。

The quality of the rotary joints greatly influences the consistency of the dual channel of polarimetric radar.Actually,the bias of Zdrvaries with azimuth and elevation because the rotary joints are asymmetric in structure due to the production process,and it affects the accuracy of using radar data for quantitative precipitation estimation and hydrometeor classification.The CW（Continuous Wave）signals of the C-band dual-polarization radar of the Nanjing University of Information Science and Technology were used to detect the measurement errors caused by the rotary joint for azimuth and elevation.The results show that the rotary joints have some influence on the measurement results of Zdr of dual polarization weather radar,and it can be seen that the effect is relatively stable,in combined with the results of VCP and RHI,which provides a basis for the correction of the errors caused by rotary joints in using radar data.