Abstract
The International Daylight Measurement Programme (IDMP) is now in progress to develop the daylight and solar radiation database which is essential to daylighting design. Cloud amount is an important measurement item closely related to the daylight and solar radiation data. The purpose of this study is development of an automatic measuring instrument of cloud amount for the IDMP. This study proposes estimation of cloud amount from color temperature of sky light. First, this paper reviews various mechanical methods of estimating cloud amount as well as surface and satellite observations. An outline of the proposed method is also given.
