Radiometric Calibration Status and Recalibration of Aster Thermal Infrared Images

In radiometric calibration of thermal infrared (TIR) images of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), the gain coefficients are given on a day-to-day basis by the prediction functions divided by periods for each detector, regressively derived from the results of long-term calibration (LTC) periodically performed. Since these functions have been updated appropriately, prediction errors on the gain coefficients will not produce significant errors for products—about 0.2 K in temperature(1.2 K at most), and about 0.003 in emissivity (0.009 at most), at 300, 320, and 340 K. If such errors are not negligible in some cases such as cross calibration and snow/ice monitoring, the recalibration equation introduced in the present paper will reduce those errors from an image used. The recalibration coefficients applied to each image can be found at the ASTER TIR Recalibration web site.