Doppler velocity calibration study for Cloud Profiling Radar on earthcare

The Cloud Profiling Radar (CPR) on EarthCARE satellite is the first spaceborne Doppler radar for cloud and precipitation. In order to calibrate Doppler velocity, the external calibration study using active radar calibrator (ARC) is needed. The ARC must have the function to measure amplitude and phase of signal for the calibration. In addition, measurement of antenna beam angle is needed because satellite velocity is contaminated to radial velocity of radar measurement. Then the feasibility experiment was performed using the transmitting signal from CPR of CloudSat. In this paper, the preliminary result is reported and the calibration performance is discussed.