Abstract.Radiative transfer calculations that utilize the scalar approximation of light produce intensity errors as large as 10% in the case of pure Rayleigh scattering. This modeling error, which arises primarily from second order scattering, is greatly reduced for flux and albedo results because of error cancellation brought about by integration over scattering angle. However, polarized light scattered from an underlying ocean surface, or from atmospheric aerosols, interacts with the pattern of Rayleigh scattered polarization to distort the error cancellation and thus incur larger flux and albedo errors.

Carbonaceous aerosols are increasingly recognized as an important atmospheric constituent. These small atmospheric particles are predominately soot produced by incomplete combustion of fossil fuels, biofuels, and outdoor biomass that generally form through condensation of vaporized organic matter “Chylek et al., 2003”. However, biogenic emissions from trees, other vegetation, and animals are also sources of carbonaceous aerosols. Elemental carbon, in the form of graphite, is the main cause of the blackness of soot; it absorbs sunlight strongly and almost uniformly across the solar spectrum. However, the graphite seldom is pure carbon, instead involving varying proportions of other atoms. Furthermore, the carbonaceous aerosols include an enormous variety of organic compounds of carbon.

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Conversion efficiency of 23% at 369 suns has been achieved for packaged AlGaAs/GaAs solar cells fabricated by organometallic vapor phase epitaxy. The design considerations and the solar cell performance in concentrated sunlight are described.

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