標準號：BS ISO 15469-2004
中文標準名稱：日光的空間分布.CIE標準普通天
英文標準名稱：Spatial distribution of daylight - CIE standard general sky
標準類型：F12
發布日期：2004/4/5 12:00:00
實施日期：2004/4/5 12:00:00
中國標準分類號：F12
國際標準分類號：17.180.20
適用范圍：This Standard defines a set of outdoor daylight conditions linking sunlight and skylight for theoretical and practical purposes. The luminance distributions given have the following characteristics: i. They are symmetrical about the solar meridian and are functions of the angular distance, Zs, between the sun and the zenith. ii. They are defined by smooth continuous functions. Such distributions are typical of cloudless skies and of those where the cloud cover is homogeneous. They provide an approximation to skies of broken cloud that is sufficiently accurate for many practical daylight calculation purposes. iii. The relative luminance at any point in the sky depends on the angle, , between that sky element and the sun, and on the angle, Z, between the sky element and the zenith. It is given in terms of two functions: the relative scattering indicatrix, f(), and the luminance gradation between horizon and zenith, (Z).