Inter-Calibration of Satellite Passive Microwave Land Observations from AMSR-E and AMSR2 Using Overlapping FY3B-MWRI Sensor Measurements

The development and continuity of consistent long-term data records from similar overlapping satellite observations is critical for global monitoring and environmental change assessments. We developed an empirical approach for inter-calibration of satellite microwave brightness temperature (T-b) records over land from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) and Microwave Scanning Radiometer 2 (AMSR2) using overlapping T-b observations from the Microwave Radiation Imager (MWRI). Double Differencing (DD) calculations revealed significant AMSR2 and MWRI biases relative to AMSR-E. Pixel-wise linear relationships were established from overlapping T-b records and used for calibrating MWRI and AMSR2 records to the AMSR-E baseline. The integrated multi-sensor T-b record was largely consistent over the major global vegetation and climate zones; sensor biases were generally well calibrated, though residual T-b differences inherent to different sensor configurations were still present. Daily surface air temperature estimates from the calibrated AMSR2 T-b inputs also showed favorable accuracy against independent measurements from 142 global weather stations (R-2 >= 0.75, RMSE <= 3.64 degrees C), but with slightly lower accuracy than the AMSR-E baseline (R-2 >= 0.78, RMSE <= 3.46 degrees C). The proposed method is promising for generating consistent, uninterrupted global land parameter records spanning the AMSR-E and continuing AMSR2 missions.