Determination of the shortwave anisotropic function for clear-sky desert scenes from Meteosat data

Abstract Determination of planetary albedo on the basis of satellite observations of reflected shortwave (SW) radiances requires taking into account the anisotropic (non-Lambertian) reflectance properties of the earth–atmosphere system, depending both on the cloud cover and the nature of the underlying, surface. One approach frequently used has been to represent these properties by a limited set of normalized bidirectional reflectance functions (BDRF) for different scene types. The construction of the normalized BDRFs used to process the Earth Radiation Budget Experiment (ERBE) measurements was based mostly on data from the sun-synchronous Nimbus-7 mission, observing close to local noon. Consequently, because desert zones are fairly restricted in latitude, only a small range of solar zenith angles was sampled. Here the authors consider, for clear-sky desert areas, the improvements that can be made using data from the geostationary satellite Meteosat, which samples all solar zenith angles that occur. The a...