Radiative Transfer in Turbid Atmospheres

[摘要] Intensities of the solar radiation diffusely reflected and transmitted by turbid atmospheres are calculated taking into account the effects of plarization and inhomogeneous startification at wavelengths of 0.45μ and 0.70μ. The aerosols are presented by particles with a real index of refraction of 1.33 and with radii distributed according to the continental model compiled by Manson. The aerosol concentration as well as the mixing ratio of aerosols to air molecules varies with height. The proportion of aerosol to Rayleigh scattering is determined for each wavelength in the light of vertical profile proposed by Elterman. Three cases of the turbidity condition including pure Rayleigh atmosphere are considered in order to study the effects of changes of aerosol concentration. The ground is assumed to be represented by a Lambert surface. Typical results are presented by isophotes of the brightness or by intensity distributions in the principal plane. General tendency of the diffusely transmitted radiation is in good agreement with observations. Brief discussions are also made about the effect of polarization and of optical stratification upon the brightness distributions.

[学科分类] 大气科学