EXPERIMENTAL STUDY OF SCATTERING IN REAL ATMOSPHERES
TECHNICAL OPERATIONS INC BURLINGTON MA
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The scattering of visible light in hazes and fogs was investigated experimentally, using balloon-borne flash bulb clusters as sources and calibrated cameras as detectors. By defocusing the cameras, measurements of both the direct and the scattered components could be obtained on the same film. Several detectors were stationed on the ground at various distances up to 15 kms from the source. Results indicate that transmission of the direct components decrease exponentially and as the inverse square of the slant range R, while scattered radiation transmission can be described by a different exponential and the inverse first power of the slant range. All transmission constants can be related to the visibility at the time of measurement. Brightness of the aureole surrounding the source decrease inversely as R to the second power sin to the second power theta, where theta is the angular distance from the source as seen by the observer. This is an average relationship applying at all distances and fog densities observed. A general expression for the total flux from a point source reaching an observer is given in terms only of the visibility and the slant range.