Spectral distribution of solar radiation. II: Global and diffuse

Abstract

AbstractMeasurements of the spectral distribution of global and diffuse solar radiation made in both wide and narrow wavebands are reported. Relationships between the ratio of diffuse to global irradiance, α, in both the visible and total solar wavebands, and atmospheric turbidity and zenith angle are developed. Narrowband measurements are analysed to yield relationships between α and spectral turbidity in the waveband 400–800 nm. The measurements indicate that atmospheric turbidity has a greater influence on both the magnitude and shape of diffuse irradiance than of global. The biological implications of the results are briefly discussed.