Natural and Artificial Illumination in Optically Thick Atmospheres.

摘要

In the analysis of target signatures it is essential that the illumination level be defined and determined for a variety of environmental conditions. This report deals primarily with two important sources of illumination, the moon and man-made flares. The illumination due the moon is calculated using an atmospheric-radiative-transfer model which includes multiple scattering by gases and particulates in the atmosphere but does not include absorption due to gases. A variety of atmospheric states is considered, from very clear atmospheres to very hazy. A detailed analysis of fogs was carried out and density profiles were calculated to represent different kinds of fogs. A mathematically exact formula was developed which allows one to calculate the surface illumination due to one or more point sources (flares). Calculations were performed to determine surface illumination in terms of distance from source, source height, height of fog layer, and visibility. Contours were plotted which illustrate the surface illumination for various flare configurations.