Sky luminance and radiance distributions: a comparison based on data from Bahrain,Israel,Japan and Europe

Abstract

Predictive models of building performance are increasingly being based on sky luminance and radiance distributions. These, though, tend to exist as separate records and the word-wide coverage is not complete: sky luminance, in particular, has been recorded at relatively few locations. It is important in practice to ensure that luminance and radiation values are consistent with each other and that radiation measurements are used to supplement the illumination records. The paper compares data from the authors’ research in several climatic regions and shows that an anisotropic model of the sky distribution can be significantly more accurate than an isotropic function. This is discussed with particular reference to shadow band correction.