We have collaborated with companies to design a solar tracker system with bifacial photovoltaics, which electric power generation to vigorous power demands in snowy climates. Since the Sun’s altitude is low in winter and the ground surface is covered by snow, we assume that the solar irradiance reaching the system is significantly influenced by reflection from the snow surface. In this paper, therefore, we consider theoretical models for the solar radiation reflected from the snow surface. We also calculated the ratio of the solar radiation reflected from the snow surface to the solar irradiance reflecting from inclined surfaces. Since Rayleigh scattering and Mie scattering have particularly important effects, we calculated the wavelength characteristics based on the examination of each parameter. As a result, assuming that the snow surface reflectance is 60%, our calculations were in good agreement with measurements taken from sunrise to sunset. When the sun passes through the meridian, the amount of solar irradiance reflected back from the snow surface was found to be 38% of the solar irradiance incident on inclined surfaces. In addition, the amount of back-reflected solar irradiance was about 22% of the daily integrated solar radiation incident on the top surface.

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