中美天气雷达回波强度标定性能分析

Calibration performance analysis on weather radar echo intensity between China and USA

天气雷达回波强度的测量误差主要由雷达系统硬件造成,会直接影响定量降水估测精度。介绍了中美业务化天气雷达回波强度的标定原理,比较了以Syscal和dBZ_0作为标定常数的雷达气象方程的两种表达形式,分析了影响回波强度测量精度的因素,即发射机功率和接收机增益的变化;并以我国新一代天气雷达(北京CINRAD/SA及杭州CINRAD/CA)和美国WSR-88D天气雷达(KTLX和KICT)为例,给出了标定常数的实际变化曲线和分析结果。对比发现,以dBZ_0作为标定常数的标定过程更稳定,有助于提高雷达数据质量。

Measurement error for echo intensity of weather radar mainly results from radar hardware and will have a direct influence on the accuracy of quantitative precipitation estimation .This paper introduces calibration principles for operational weather radars of China and USA .In addition ,it compares two expression forms for weather radar equation using Syscal and dBZ0 as calibration constant respectively .Moreover ,it analyzes factors that affect measurement accuracy of echo intensity ,namely ,variations in transmitter power and receiver gain .What is more ,taking CINRAD radars（Beijing CINRAD/SA and Hangzhou CINRAD/CA ） and WSR-88D （KTLX and KICT ）radars as examples ,it presents practical variation curves and analysis results for calibration constants .By comparison ,it can be found that calibration process using dBZ0 as calibration constant is more stable and hence is helpful for improving radar data quality .