Accession Number : ADA111823

Title :   An Operational Technique for Estimating Visible Spectrum Contrast Transmittance.

Descriptive Note : Interim rept.,

Corporate Author : SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA VISIBILITY LAB

Personal Author(s) : Hering,Wayne S

PDF Url : ADA111823

Report Date : Jun 1981

Pagination or Media Count : 33

Abstract : Simultaneous optical and meteorological measurements between ground level and 6 km gathered by the Visibility Laboratory in recent years in the United States and Europe with an instrumented aircraft have provided the basis for the development of a technique for estimating atmospheric path radiance and directional contrast transmittance. The technique is relatively fast and easy to apply yet is designed to take full advantage of the present capability to observe and predict the relevant atmospheric variables. Various modelling approximations are introduced to simplify the calculations of radiative transfer and to help specify the vertical distribution of atmospheric attenuation coefficient and the single scattering phase function. Critical examinations of the assumptions and approximations were made through reference to the extensive series of airborne meteorological/optical measurements. Model input parameters are the number of atmospheric layers selected and the average optical scattering ratio and single scattering albedo for each layer, the solar zenith angle, the extra-terrestrial solar irradiance, a representative wavelength and the surface reflectance. The computer code calculates the path radiance corresponding to any selected point and direction and the contrast transmittance for any slant atmospheric path. The changes in image transmittance characteristics that are associated with the natural variations in environmental physical parameters are examined through systematic application of the modelling techniques.

Descriptors :   *ATMOSPHERIC PHYSICS, *TROPOSPHERE, *VISIBLE SPECTRA, *LIGHT TRANSMISSION, *CONTRAST, LIGHT SCATTERING, RADIATION ATTENUATION, COEFFICIENTS, FUNCTIONS(MATHEMATICS), ATMOSPHERE MODELS, COMPUTERIZED SIMULATION, MATHEMATICAL MODELS

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE