A Study on Correlation Between Daylight Illuminance and Solar Radiation Based on Data From Long-Term Measurement

摘要

As part of the International Daylight Measurement Programme (IDMP) proposed by CIE, the authors have been observing daylight illuminance and solar radiation very closely in Chofu city, Tokyo since December 1992. The authors sought a correlation between daylight illuminance and solar radiation, using data collected every minute for five years between January 1, 1993 and December 31, 1997 among the data from the above-mentioned observation. It was discovered that the luminous efficacy of the total component was 127lm/W, that of the diffuse component 145lm/W and that of the direct component 102lm/W.