The Interaction of Solar Radiation with Earth’s Atmosphere: Modeling the Total Atmospheric Transmittance by a Regression Function
Résumé
In this investigation, a numerical simulation has been performed based on the SMARTS2 model to study the influence of the zenith angle on the variation of the total atmospheric transmittances. This calculation has been made for ultraviolet and visible light in the range of [0.2, 0.39 µm] and [0.4, 0.75 µm], respectively by taking into account the absorption and the scattering of radiation by the atmospheric gas molecules as well as aerosols. In order to determine the direct dependence of the total atmospheric transmittance on the light wavelength, a regression approach has been used for four values of zenith angles [0°, 25°, 35°, 57°]. The result shows that total atmospheric transmittance can be modeled by a polynomial function of sixth order which describes fairly the atmospheric transmittance as a function of wave length and zenith angle. More importantly, the comparison between our present results and Modtran’s results shows a good agreement with relative reduction ratio of transmission equals approximately to 1.