X波段双偏振雷达垂直指向法标定的应用

Application of Vertical Detection Calibration on X-band Dual Polarization Radar

垂直指向法标定是双偏振雷达的差分反射率因子ZDR标定有效方法的一种,可以订正ZDR测量误差,提高雷达数据的质量。本文基于双发双收模式的X波段双线偏振天气雷达系统,通过分析雷达硬件系统和垂直指向法标定的数据,诊断了观测数值的一些质量问题,初步判断是方位旋转关节损坏而导致ZDR的数值在某一固定区域上出现较大偏差。更换新的方位旋转关节后,对比处理问题前后的垂直指向标定数据证明能有效解决此问题。最后,经过多次试验分析表明,当垂直指向法标定在回波强度为25.5~30.5dB之间的中等范围稳定的层状云降水情况下使用时,其标定的数据能有效订正系统ZDR偏移量。

Vertical detection calibration is an effective way to calibrate the differential reflectivity（ZDR）of dual-polarization radar,it can correct measurement errors of ZDR,and improve the quality of the radar data.Based on the simultaneous transmission and reception mode of the X-band dual-polarization radar system,the ZDR product of the X-band dual polarization radar system has a large deviation in some areas,and it can preliminarily concluded that such problem is caused by the azimuth rotary joint by analyzing the radar hardware system and data of the vertical detection calibration.After replacing the damaged with new azimuth rotary joint,this problem can be solved well,which can be verified by the comparing of the data before and after this replacement.Several tests show that the data of vertical detection calibration can correct the ZDRoffset effectively when using in the condition of medium-scale stratiform precipitation with the echo intensity between 25.5 dB and 30.5 dB.