Daylight

About: Daylight is a research topic. Over the lifetime, 4267 publications have been published within this topic receiving 58949 citations. The topic is also known as: the light of day.

Spectral Distribution of Typical Daylight as a Function of Correlated Color Temperature

Abstract: Spectral distributions of 622 samples of daylight (skylight, and sunlight plus skylight) have been subjected to characteristic vector analysis, as composite data and in three subgroups (99 distributions measured by Budde; 249, by Condit; and 274, by Henderson and Hodgkiss). The chromaticity coordinates (x,y) computed from these distributions have been compared with direct visual determinations of chromaticity coordinates of daylight by Nayatani and Wyszecki, and by Chamberlin, Lawrence, and Belbin. It was found that the chromaticities indicated by the spectral distributions and by direct visual colorimetry cluster about the curve: y = 2.870x−3.000x2−0.275. This curve of typical daylight chromaticities falls slightly on the green side of the Planckian locus. From the mean and the first two characteristic vectors of the composite data, spectral distribution curves have been reconstituted by choice of scalar multiples of the vectors such that the chromaticity points fall on the curve of typical daylight chromaticities at places corresponding to correlated color temperatures of 4800°, 5500°, 6500°, 7500°, and 10 000°K. The representative character of these reconstituted spectral-distribution curves has been established by comparison with the measured curves from each subgroup yielding the closest approximation to the same chromaticities. The agreement so found suggests that this family of curves is more representative of the various phases of daylight between correlated color temperatures 4800° and 10 000°K than any previously derived distributions.

Winter Blues: A SAD Stock Market Cycle

Abstract: And God said, Let there be light; and there was light. And God saw that the light was good. Genesis 1:3 Depression has been linked with seasonal affective disorder (SAD), a condition that affects many people during the seasons of relatively fewer hours of daylight. Experimental research in psychology has documented a clear link between depression and lowered risktaking behavior in a wide range of settings, including those of a financial nature. Through the links between SAD and depression and between depression and risk aversion, seasonal variation in length of day can translate into seasonal variation in equity returns. Based on supportive evidence from psychology which suggests SAD is linked closely with hours of daylight, we consider stock market index data from countries at various latitudes and on both sides of the equator. We model differences in the seasonal variation of daylight across coun

Dynamic Daylight Performance Metrics for Sustainable Building Design

Abstract: The objective of this document is to promote the use of dynamic daylight performance measures for sustainable building design. The paper initially explores the shortcomings of conventional, static daylight performance metrics which concentrate on individual sky conditions, such as the common daylight factor. It then provides a review of previously suggested dynamic daylight performance metrics, discussing the capability of these metrics to lead to superior daylighting designs and their accessibility to nonsimulation experts. Several example offices are examined to demonstrate the benefit of basing design decisions on dynamic performance metrics as opposed to the daylight factor.