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RESEARCH PRODUCT

Scattered Radiation in the Atmosphere and the Natural Aerosol

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Publisher Summary This chapter deals with problems of scattered atmospheric radiation, with regard to the haze in the atmosphere. The impressive phenomenon of the tint of the sky, which varies with the time of day and with the weather situation, has long stimulated the investigation of the radiation of the sky. As it is known that the sky radiation is in part, strongly polarized and that the degree of polarization is subjected to characteristic variations, these facts are included in the investigation. The atmospheric transparency for radiation and especially the radiation effects as related to aerosols of certain sizes are of fundamental importance. Reflected and scattered radiations are essential components of the atmospheric radiation balance and play an important role in the heat balance of the earth. The direct solar radiation reaching an observer on the ground is only a portion of the solar radiation entering the earth's atmosphere; a portion will be absorbed in the atmosphere; a portion will be scattered. The scattered portion is partly diffused back to space, while the remainder reaches the ground as sky radiation. The portion of the solar and sky spectrum, which accounts for the highest proportion of the total energy transmitted, i.e., from 0.4 to 1 p, undergoes extinction almost exclusively due to scattering; therefore, the scattering laws of atmospheric radiation are of great importance. If the atmosphere were composed only of air molecules, the knowledge of their scattering laws would be sufficient. The atmosphere, however, also includes haze aerosol, which is subject to other scattering laws. This aerosol is understood to be composed of all solid or liquid particles suspended in the atmosphere, with their size ranging from about 0.03 to 20 p. Cloud drops and hydrometeors are excluded.