The effect of a concentrated turbid layer on the polarization of skylight is discussed in this paper. Two idealized models of the turbid atmosphere are employed. In one an aerosol layer is situated below a molecular layer and, in the other, above it. The size distribution of the aerosols of refractive index 1.33 is assumed to follow a power law. Inside the aerosol layer, only primary scattering of light is taken into account and polarization effects are neglected. The importance of the interaction between the aerosol and molecular layers is recognized. The resulting computations show broad agreement with available observations. The importance of the location of the turbid layer in characterizing the emergent radiation is revealed. In particular, the computations have shown that the Babinet and Brewster neutral (zero polarization) points can shift towards the sun from their normal positions in a molecular atmosphere when there is low-level turbidity. Such a shift is indicated by observations.
MUNEYASU KANO, "Effect of a Concentrated Turbid Layer on the Polarization of Skylight," J. Opt. Soc. Am. 58, 789-797 (1968)