Reprocessing 12-yr Microwave Humidity Sounder Historical Data of Fengyun-3 Satellites

Atmospheric water vapor is an essential climate variable (ECV) with extensive spatial and temporal variations. Microwave humidity observations from meteorological satellites provide important information for climate system variables, including atmospheric water vapor and precipitable water, and assimilation in numerical weather prediction (NWP) and reanalysis. As one of the payloads onboard China’s second-generation polar-orbiting operational meteorological Fengyun-3 (FY-3) satellites, the Microwave Humidity Sounder (MWHS) has been continuously observing the global humidity since 2008. The reprocessing of historical FY-3 MWHS data is documented in detail in this study. After calibrating and correcting the data, the quality of the reprocessed dataset is evaluated and the improvement is shown in this study. The results suggest that MWHS observations bias is reduced to approximately 0.8 K, compared with METOP-A Microwave Humidity Sounder (MHS). The temporal variability of MWHS is highly correlated with the instrument temperature. After reprocessing, the scene temperature dependency is mitigated for all 183 GHz channels, and the consistency and stability between FY-3A/B/C are also improved.