Diffuse sky radiation is
solar radiation reaching the
Earth's surface after having been
scattered from the direct solar beam by
molecules or
suspensoids in the
atmosphere. It is also called
skylight,
diffuse skylight, or
sky radiation and is the reason for changes in the color of the sky. Of the total
light removed from the direct solar beam by scattering in the atmosphere (approximately 25% of the incident radiation when the sun is high in the sky, depending on the amount of dust and haze in the atmosphere), about two-thirds ultimately reaches the earth as diffuse
sky radiation.