Effects of surface and atmospheric aerosols on several POLDER channels

Atmospheric aerosol enhance greatly the atmospheric scattering which decrease the signal to noise ratio of the satellite images. It is therefore important to correctly estimate and remove the effects of the atmospheric aerosols on signals from the underlying surfaces. Depth of the absorption band of oxygen molecules at 760 nm wavelength will be changed by multiple scattering. The new generation of space-borne spectrometers under development provides sufficient spectral resolution to detect this effect. This paper discuses the possibility to distinguish the type of aerosols and retrieve aerosol optical depth from the variation of the features of the A-band at 760 nm. It is shown that this effect can be used to classify aerosols when aerosol optical depth is very large or for cases over typical land surfaces. For the visibility ranging from 5 to 20 km. Aerosol optical depth can be retrieved accurately over the ocean even if the type of aerosols is unknown. Therefore, this method can provide valuable information to current atmospheric correction and spaceborne aerosol-retrieval schemes.