Surface albedo retrieval from Meteosat - 2. Applications

An advanced algorithm to retrieve the radiative properties of terrestrial s urfaces sampled by the Meteosat visible instrument was derived in a compani on paper [Pinty et al., this issue]. Preliminary applications of this algor ithm against a limited set of Meteosat data is performed and the required p rocedures to screen "clear-sky" conditions only and to retrieve the "likely " solution of the inverse problem are presented and evaluated. The accumula tion of results over two periods of 20 days each during the Northern Hemisp here summer and winter permits establishing sample geophysical maps of the algorithm products, including the surface albedo (i.e., directional hemisph erical reflectance factors) over the entire African continent. The seasonal albedo changes occurring at a continental scale are interpreted on the bas is of the most prominent environmental factors, namely the atmospheric circ ulation controlling the seasonal monsoon events and the biomass burning act ivities. The results of this study, supported by additional radiation trans fer simulations, suggest that anthropogenic fire activities induce signific ant perturbations of the surface albedo values in the intertropical zones a t the continental scale.