Abstract
To confirm the accuracy of on-board calibration (OBC) of the thermal infrared bands of Terra ASTER and Landsat-7 ETM+, vicarious calibration (VC) and cross calibration (CC) methods were proposed and applied to field and airborne data. For VC at Salton Sea and Railroad Valley, US, ground temperature was measured in large areas with homogenious temperature and emissivity during overpasses of these satellites. Radiance-based calibration of ASTER TIR was conducted using a multispectral radiometer with the same spectral coverage as ASTER TIR. For CC at Lake Tahoe, airborne MASTER data were acquired when these satellites passed. We proposed a method in which the spectral difference between the satellite and the airborne sensor is considered. Atmospheric parameters were determined by MODTRAN4 from atmospheric profiles obtained with the radiosonde launched during experiments. Calibration results show that the radiant temperature of ASTER TIR (Level 1 B Ver. 0.4) is 0.2-1.3°C lower than those of VC/CC at high temperature (15-40°C). ETM+ (Level 1 R using calibration coefficients determined before December 20, 2000) estimates the radiant temperature 3°C (except in Railroad Valley) higher than VC/CC. VC/CC accuracy was better than 1°C (radiometric calibration requirement of ASTER TIR at 270-340K).
