New Algorithm Unlocks FY-3G Satellite's Rainfall Secrets

Researchers from the University of Science and Technology of China, the National Satellite Meteorological Center, the Meteorological Observation Centre of the China Meteorological Administration, and collaborators have developed the first systematic precipitation retrieval algorithm for China's Fengyun-3G (FY-3G) satellite. The algorithm converts passive microwave observations from the MWRI-RM radiometer into an operational product describing surface rainfall and hydrometeor profiles. Published (DOI: 10.34133/remotesensing.1057) on August 11, 2026, in the Journal of Remote Sensing, the study addresses a critical gap: FY-3G collects rich passive microwave information, but no dedicated method had fully exploited these channels to generate an operational precipitation product. The framework retrieves surface precipitation and vertical hydrometeor structure, producing a multiple-hydrometeor profile (MHP) product that agreed well with established Global Precipitation Monitoring (GPM) products—GPROF and CMB—in surface precipitation rate, rainwater path, and ice water path patterns.

Surface precipitation estimates generally showed relative mean biases within 14% over ocean and land, and the MHP product demonstrated a markedly stronger relationship between cloud liquid water path and precipitation intensity than either comparison product, indicating a more physically realistic cloud–rain linkage. Calibration tests showed strong agreement between simulated and observed brightness temperatures, with Pearson correlations exceeding 0.94 under clear skies. In a typhoon case, all three products captured the eyewall and three spiral rainbands, but MHP achieved a cloud-liquid-water-to-rainfall spatial correlation of 0.84, versus 0.72 for GPROF and 0.52 for CMB. Validation against 2,486 rain gauges showed that extending accumulation from 10 to 60 minutes increased correlation from 0.455 to 0.542 and reduced RMSE from 1.743 to 1.341 mm/h. The authors note that "the MHP product exhibits good consistency with GPROF and CMB" and that its precipitation-related variables can reveal storm microphysics and support improved model parameterization. The team also sees potential for extending the retrieval framework beyond FY-3G to other Fengyun microwave imagers and future satellite missions.

The prototype could strengthen operational precipitation monitoring over China and globally, especially where ground networks are sparse. Because MHP retrieves rainfall together with cloud and frozen-water structure, it may support typhoon and flood monitoring, cloud–precipitation research, climate-model evaluation, and improved microphysical parameterization. Further refinement of heavy-rain representation, high-elevation retrievals, and ice-particle models could improve accuracy and broaden future operational use.