A frequency correction algorithm for spaceborne precipitation measurement radar and ground-based weather radar

By combining the bright band model used in the GPM retrieval algorithm and Mie scattering calculation, the lookup table of scattering functions is generated for three types of precipitation, i.e., solid precipitation, liquid precipitation and mixed phase precipitation. The accuracy of the lookup table is verified by comparing with the measured data of GPM. The result shows that the maximum deviation of scattering calculation is less than 0.5 dB. Based on the lookup table, the frequency correction from spaceborne Ku band radar to S-band radar is completed. The analysis of the scattering function shows that the frequency correction from Ku band to S band depends on the phase and spectral parameter $D_{\mathrm{m}}$. Among them, the frequency correction of liquid precipitation is mainly negative, and the maximum is not more than −3 dB. The frequency correction of mixed phase precipitation varies significantly with the height of the 0℃ bright band. The frequency correction of solid precipitation is positive without a 0℃ bright band. When there is a 0℃ bright band, it changes significantly with temperature. The method proposed in this paper can be used to realize the frequency correction between satellite and ground radars in different bands, and provide effective support for consistency inspection of detection accuracy of spaceborne radar.