双发双收双偏振天气雷达差分反射率工程标定方法

分析了利用小雨、太阳、边界层顶的Bragg散射、地物等外界目标对双偏振天气雷达差分反射率(Zdr)进行标定的原理和局限性,介绍了一种可以在线获得发射机、接收机和天线引入的Zdr偏差的工程标定方法,并提出了一种提高Zdr测量精度的方法,即在每个脉冲重复周期,实时测量每个通道的发射功率耦合测试信号和气象目标回波信号在接收机数字中频的输出值,用于补偿发射功率和接收机增益的变化。该文介绍的两种工程标定方法可用于水平通道和垂直通道同时发射同时接收的双偏振天气雷达系统,能够满足在线实时标定的业务运行要求。

Engineering Calibration Methods for Differential Reflectivity of Dual Polarization Weather Radar in Simultaneous Transmission and Reception Mode

An analysis is made of the calibration principles and limitations for differential reflectivity （Zdr） Of dual polarization weather radar using external targets such as drizzle, sun, Bragg scattering at the top of the convective boundary layer and ground clutter. An engineering calibration method that can obtain the Zdr bias induced by transmitter, receiver, and antenna online is presented. In addition, a method is put forward to improve Zdr measurement accuracy, which compensates variations in transmitted power and receiver gain by measuring coupled transmitted power and backscattered power of meteorological targets at the output of digital receiver during each pulse repetition time in horizontal and vertical channels, respectively. These two engineering calibration methods are applicable to radar that simultaneously transmit and receive waves in horizontal and vertical polarization channels and can satisfy operational requirements for online calibration.