RE-Calibration of MWRI Onboard FY Series Satellites

A re-calibration algorithm of MWRI (Microwave Radiation Imager) onboard FengYun series satellites was developed based on the error budget analysis of MWRI and the main calibration parameters simulation and iteration. SNO (Simultaneous Nadir Overpass) between MWRI and GMI were used to get the brightness temperature of stable radiation target including sea surface and rain forest. Based on those brightness temperature datasets of stable target, DD (double difference) were used with RTTOV simulation result to cancel the effect of different sensor parameters between MWRI and GMI. Finally, emissivity of hot reflector, back lobe of hot reflector, efficiency of hot load, non-linearity parameter of MWRI were simulated and corrected. Using the corrected parameters, re-calibration of MWRI was done and we get the 10 years’ time series dataset. Validation result shows that the dataset has very high accuracy and stability compared with operational dataset.