The Landsat-5 (L5) Thematic Mapper (TM) radiometric calibration procedures have been revised to improve accuracy and consistency with Landsat-7 (L7) Enhanced Thematic Mapper Plus (ETM+) data. Effective May 5, 2003, the U.S. Geological Survey (USGS) Earth Resources Observation System (EROS) Data Center (EDC) will use a new calibration method and revised parameters. This change aims to enhance the absolute calibration accuracy, consistency over time, and consistency with L7 ETM+ data. Users must use new parameters to convert calibrated data products to radiance. The new procedure for reflective bands (1–5,7) is based on a lifetime radiometric calibration curve derived from the instrument's internal calibrator, cross-calibration with the ETM+, and vicarious measurements. The thermal band continues to be calibrated using the internal calibrator. Further updates to improve relative detector-to-detector calibration and thermal band calibration are being investigated, as is the calibration of the Landsat-4 (L4) TM. The revised calibration method involves time-dependent calibration lookup tables (LUTs) generated from lifetime gain equations. This approach replaces the previous scene-by-scene calibration using the internal calibrator. The new method also applies biases line-by-line based on dark shutter responses and discards regression-based offsets. This will correct for scan-correlated shift (SCS) radiometric artifacts. Calibration of the thermal band continues with the current IC-based approach. The thermal band gain is affected by ice buildup on the cold focal plane window, but analyses suggest it is behaving as expected. The calibration of this band is accurate to within 1°C. For Level 1 products, radiance is calculated using a formula that converts calibrated digital numbers (DNs) to spectral radiance. The equation used is $ L_{\lambda} = G_{rescale} \times Q_{cal} + B_{rescale} $, where $ G_{rescale} $ and $ B_{rescale} $ are band-specific rescaling factors. Table I provides band-specific $ LMAX_{\lambda} $ and $ LMIN_{\lambda} $ parameters and corresponding rescaling factors. Radiance is converted to top-of-atmosphere (TOA) reflectance using a formula that accounts for solar irradiance and solar zenith angle. The reflectance calculation depends on the earth-sun distance, which is provided in Table III. Thermal band data (band 6) can be converted to effective at-satellite temperature using a formula that assumes unity emissivity. The formula is $ T = \frac{K2}{\ln(\frac{K1}{L_{\lambda}} + 1)} $, where $ K1 $ and $ K2 $ are calibration constants. The revised calibration method improves the radiometric accuracy of L5 TM data, allowing for reThe Landsat-5 (L5) Thematic Mapper (TM) radiometric calibration procedures have been revised to improve accuracy and consistency with Landsat-7 (L7) Enhanced Thematic Mapper Plus (ETM+) data. Effective May 5, 2003, the U.S. Geological Survey (USGS) Earth Resources Observation System (EROS) Data Center (EDC) will use a new calibration method and revised parameters. This change aims to enhance the absolute calibration accuracy, consistency over time, and consistency with L7 ETM+ data. Users must use new parameters to convert calibrated data products to radiance. The new procedure for reflective bands (1–5,7) is based on a lifetime radiometric calibration curve derived from the instrument's internal calibrator, cross-calibration with the ETM+, and vicarious measurements. The thermal band continues to be calibrated using the internal calibrator. Further updates to improve relative detector-to-detector calibration and thermal band calibration are being investigated, as is the calibration of the Landsat-4 (L4) TM. The revised calibration method involves time-dependent calibration lookup tables (LUTs) generated from lifetime gain equations. This approach replaces the previous scene-by-scene calibration using the internal calibrator. The new method also applies biases line-by-line based on dark shutter responses and discards regression-based offsets. This will correct for scan-correlated shift (SCS) radiometric artifacts. Calibration of the thermal band continues with the current IC-based approach. The thermal band gain is affected by ice buildup on the cold focal plane window, but analyses suggest it is behaving as expected. The calibration of this band is accurate to within 1°C. For Level 1 products, radiance is calculated using a formula that converts calibrated digital numbers (DNs) to spectral radiance. The equation used is $ L_{\lambda} = G_{rescale} \times Q_{cal} + B_{rescale} $, where $ G_{rescale} $ and $ B_{rescale} $ are band-specific rescaling factors. Table I provides band-specific $ LMAX_{\lambda} $ and $ LMIN_{\lambda} $ parameters and corresponding rescaling factors. Radiance is converted to top-of-atmosphere (TOA) reflectance using a formula that accounts for solar irradiance and solar zenith angle. The reflectance calculation depends on the earth-sun distance, which is provided in Table III. Thermal band data (band 6) can be converted to effective at-satellite temperature using a formula that assumes unity emissivity. The formula is $ T = \frac{K2}{\ln(\frac{K1}{L_{\lambda}} + 1)} $, where $ K1 $ and $ K2 $ are calibration constants. The revised calibration method improves the radiometric accuracy of L5 TM data, allowing for re