The Precipitation Measurement Radar (PMR) onboard FengYun-3G consists of a Ku-/Ka-band radar, which is characterized by similar configurations with the Dual-frequency Precipitation Radar (DPR) carried by Global Precipitation Measurement mission Core Observatory. However, directly comparing observations from two radars is challenging due to a scarcity of their coincidences. In this study, sea surface echoes in their track intersections were employed to cross-calibrate PMR. Then, we show that the dual-frequency ratio (DFR) in snow stably increases with Ku-band reflectivity in statistics, allowing for an assessment of the consistency between PMR and DPR observations. Surprisingly, our results reveal a underestimation of DFR in DPR inner swath, while observations from PMR are in good agreement with those from DPR outer swath. This study demonstrates the novel use of natural targets for spaceborne dual-frequency radar calibration, and presents a unique view into the connection between the two spaceborne precipitation radar missions in operation.

FengYun-3G, Precipitation Measurement Radar, Global Precipitation Measurement, Dual-frequency Precipitation Radar