Accuracy Evaluations of the CRCS In-orbit Field Radiometric Calibration Methods for Thermal Infrared Channels

In order to achieve the in-orbit absolute radiometric calibration of the operational meteorological satellites’ thermal infrared channels, China Radiometric Calibration Sites (CRCS) were established and the accuracy of the CRCS in-orbit field absolute radiometric calibration methods (FCM) for thermal infrared channels (TIR) was evaluated and analyzed based on TERRA/AQUA MODIS observations. Comparisons between the MODIS at pupil brightness temperatures (BTs) and the simulated BTs at the top of atmosphere using radiative transfer model (RTM) based on field measurements showed that the accuracy of the current in-orbit field absolute radiometric calibration methods was better than 1.0K (@ 300K) in thermal infrared channels. Therefore, the current CRCS field calibration method for TIR channels applied to Chinese meteorological satellites was with favorable calibration accuracy: for 10.5~11.5 μm channel was better than 0.747 K and for 11.5~12.5 μm channel was better than 0.851 K.