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Computing Clear Day Solar Radiation Spectra for the Terrestrial Ecological Environment
Author(s) -
McCullough Edwin Charles,
Porter Warren P.
Publication year - 1971
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1933806
Subject(s) - atmosphere (unit) , zenith , solar zenith angle , latitude , longitude , environmental science , atmospheric sciences , sky , cloud cover , elevation (ballistics) , spectral line , radiation , elevation angle , diffuse sky radiation , flux (metallurgy) , physics , meteorology , remote sensing , geology , astronomy , optics , scattering , cloud computing , chemistry , organic chemistry , computer science , operating system , azimuth
Clear sky (cloud—free) horizontal plane terrestrial solar radiation spectral fluxes can be computed for any time of day and year, geographic location (latitude and longitude), and elevation upon inputing the optical properties of the atmosphere and reflecting properties of the underlying surface. Consideration is given to the problem of diffuse terrestrial radiation spectra for non—sea level elevations and where the terrestrial atmosphere cannot be regarded as being purely a Rayleigh atmosphere. Computation of terrestrial spectra for "large" zenith angles (Z > or = 72 degrees) is considered along with a discussion of irradiation patterns peculiar to polar zones (i.e., long days and nights). Selected results from the integration of these concepts into a computer program include the computation of total diffuse—to—direct flux ratios for radiation from a Rayleigh atmosphere at any solar zenith angle and selected elevations with typical mean ground albedos. Comparisons of integrated energy predictions with measurements in the literature agree favorably.