Surface Reflectance Earth System Data Record / Climate Data Record

Directional surface reflectance is defined as the ratio between the radiance measured in specific observation geometry (zenith and azimuth) and a direct source of illumination (zenith and azimuth) in an infinitely small solid angle. The directional surface reflectance is determined from satellite observations though the atmospheric correction process. When properly retrieved, the directional reflectance is fully decoupled from the atmospheric signal, and thus represents the value that would be measured by an ideal sensor held at the same sun-view geometry and located just above the Earth’s surface if there was no atmosphere.