The paper by Gyanesh Chander and Brian Markham discusses the revised radiometric calibration procedures and postcalibration dynamic ranges for the Landsat-5 Thematic Mapper (TM) data processed and distributed by the U.S. Geological Survey (USGS) Earth Resources Observation System (EROS) Data Center (EDC). Effective May 5, 2003, the calibration will be improved using a new procedure and revised parameters, enhancing absolute calibration accuracy and consistency over time. The reflective bands (1–5, 7) are calibrated based on a lifetime radiometric calibration curve derived from the instrument’s internal calibrator, cross-calibration with the Landsat-7 Enhanced Thematic Mapper Plus (ETM+), and vicarious measurements. The thermal band continues to be calibrated using the internal calibrator. The paper also provides methods and parameters for converting digital numbers (DNs) from image data to useful quantities such as spectral radiance, top-of-atmosphere reflectance, and temperature estimates. The new calibration approach aims to correct for time-dependent changes in the instrument’s response, improving the reliability of the calibration. The paper concludes that the improved calibration is expected to achieve a radiometric accuracy of ±5% and will enhance the long-term studies of Earth's land surfaces.The paper by Gyanesh Chander and Brian Markham discusses the revised radiometric calibration procedures and postcalibration dynamic ranges for the Landsat-5 Thematic Mapper (TM) data processed and distributed by the U.S. Geological Survey (USGS) Earth Resources Observation System (EROS) Data Center (EDC). Effective May 5, 2003, the calibration will be improved using a new procedure and revised parameters, enhancing absolute calibration accuracy and consistency over time. The reflective bands (1–5, 7) are calibrated based on a lifetime radiometric calibration curve derived from the instrument’s internal calibrator, cross-calibration with the Landsat-7 Enhanced Thematic Mapper Plus (ETM+), and vicarious measurements. The thermal band continues to be calibrated using the internal calibrator. The paper also provides methods and parameters for converting digital numbers (DNs) from image data to useful quantities such as spectral radiance, top-of-atmosphere reflectance, and temperature estimates. The new calibration approach aims to correct for time-dependent changes in the instrument’s response, improving the reliability of the calibration. The paper concludes that the improved calibration is expected to achieve a radiometric accuracy of ±5% and will enhance the long-term studies of Earth's land surfaces.