Accession Number : AD0672308

Title :   COLORIMETRIC DESCRIPTION OF RADIATION EMERGING FROM THE TOP OF A RAYLEIGH ATMOSPHERE,

Corporate Author : CALIFORNIA UNIV LOS ANGELES DEPT OF METEOROLOGY

Personal Author(s) : Rao,C. R. Nagaraja

Report Date : APR 1968

Pagination or Media Count : 22

Abstract : The trichromatic coefficients of light emerging from the top of a plane parallel, purely scattering Rayleigh (molecular) atmosphere have been computed. The extraterrestrial illumination from the sun is approximated with illumination from the CIE standard illuminant C. The ground is assumed to reflect radiation according to the Lambert law. The results are expressed in terms of the dominant wavelength and associated values of excitation purity. It is found that when the diffuse reflectivity of the ground assumes moderate to high values (0.25 to 0.8), the excitation purity of the emergent light is so small as to cause an overall 'neutral grey' or 'neutral white' appearance. On the other hand when the ground is non reflecting or when the diffuse reflectivity is very low, the dominant wavelength of the emergent radiation lies in the blue region and the associated excitation purity exhibits fairly high values (40%). It is possible that computations such as the above, when extended to more realistic models of the atmosphere, may find application in problems related to color-photographic reconnaissance from high altitudes. (Author)

Descriptors :   (*ATMOSPHERE MODELS, *COLORIMETRY), COLOR PHOTOGRAPHY, AERIAL PHOTOGRAPHY, RAYLEIGH SCATTERING, OPTICAL PROPERTIES

Subject Categories : Atmospheric Physics
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE