Chapter 2

Fig. 2: Because of absorption and scattering by the atmosphere, the spectral distribution of solar radiation outside the atmosphere differs significantly from that on earth. Also, the spectral distribution on earth changes throughout the day and year and is influenced by location, climate, and atmospheric conditions. Consequently, the percentage of energy that is composed of UV, visible, or near-infrared radiation, or portions thereof, also varies by location, time of day, and year.