干旱区生态环境知识资源中心

The charge-coupled device (CCD) is visible to near-infrared imaging sensors onboard the Chinese Huan Jing 1 satellites. Like many sensors, the CCD lack onboard calibration capabilities, so alternative methods are required, e. g., cross-calibration. The wide field of view of the CCD sensors provides challenges for cross-calibration with narrow field of view sensors. We developed a technique to take advantage of a site with a uniform surface material and a natural topographic variation. Due to the topography, near-nadir Landsat Enhanced Thematic Mapper (TM) Plus(ETM+) observations actually see the material at a wide range of illumination and viewing angles. These observations and Advanced Spaceborne Thermal Emission and Reflection Radiometer global digital elevation model data were used to develop a model of this site’s bidirectional reflectance distribution function that covered most of the illumination and view angle range of the CCD data. We validated this model by comparing the simulations to actual ETM+ and TM surface reflectances. The validated model was then used to calibrate the CCD instruments. The results were consistent to within 5% of field intensive vicarious calibration data.