Abstract
The intensity and the degree of polarization of the radiation diffusely reflected by turbid atmospheres are calculated in the visible region of wavelengths, 0.36, 0.40, 0.50 and 0.60μm. The underlying surface is assumed to reflect light in accordance with the Lambert law. Deirmendjian modified Gamma function (1969) and Junge power law (1963) are adopted for their aerosol size distributions. Their refractive indices are 1.34 and 1.50 in the real part, while the imaginary part is assumed to be zero. The values of the optical thicknesses of aerosols are obtained from the work of Rao et al, 1973. The objective of this work is to estimate the optical properties of the aerosols such as size distribution and refractive index by comparing the remote sensing satellite measurements with computed values of the intensity and the degree of polarization of radiation emerging from the top of the model atmospheres. The doubling method (Hansen, 1971) and the adding method (Takashima, 1973) were used for the numerical computations. Computational results show that a strong dependence of the phase matrix of aerosols exists on the diffuse reflection radiation especially at the anti-solar point, showing that (1) the intensity and degree of polarization is a smooth function in the sun vertical if m=1 .34, and if m=1.50, (2) a large intensity value of radiation is observed due to a strong back scattering by the aerosols, and (3) the characteristic polarization curve exists at the anti-solar point. Towards the end of this paper, brief discussions are made for the assumptions employed.
