Despite the difficulty for separating these two contributions, polarized light provides probably a better means that total 
light for discriminating surface from atmospheric effects. For this discrimination, the different behaviors of the surface 
and atmosphere contributions with respect to the wavelength and the viewing geometry are helpful, but the principal 
point seems to be that polarized reflectances of surface pixels exhibit lower variability than total reflectances for no 
grazing viewing directions. For large enough aerosol contents, aerosol retrieval from the polarized light observed in 
these geometries should therefore be possible; the surface contribution could be accounted for by some standard 
correction term. The surface polarization is certainly accessible in clear sky conditions. More generally, its 
information content is mainly localized in grazing directions where this signal seems to increase faster than the 
atmospheric one. It must be noted that, because of the earth sphericity, the satellite version of POLDER will have a 
larger field of view than the aircraft version. 
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