Determination of CIE Standard General Sky from horizontal and vertical illuminance/ irradiance

摘要

The CIE Standard General Sky defines the luminance distribution of skies into 15 types, from overcast sky to clear sky. This study presents a method where the ratio of vertical diffuse illuminance (or irradiance) to the horizontal sky illuminance (or irradiance) can be used to classify a sky into one of the CIE standard skies.