Implementation of a reconstructed spectral sky definition in a light simulation tool and comparison to measurements

Lark is a spectral light simulation tool that emerged to optimize indoor light exposure for ipRGC-influenced light (IIL) responses which play a significant role in our physiological and psychological health. Lark provides two sky spectrum models – D65 Standard Illuminant and measurements of sky spectral power distribution, both of which present limitations. D65 Standard Illuminant is an average sky spectrum based on measurements taken in locations in 45°N–55°N latitude range and may result in inaccuracies for locations outside of this range and for certain times of the day and year. Measurements of sky spectral power distribution, on the other hand, are very accurate, however, inaccessible to most users due to cost of equipment and lack of publicly available data. These limitations can be addressed by Occupant Wellbeing through Lighting (OWL), another spectral light simulation tool. OWL reconstructs a spectral power distribution for a given time and location, and its components can be implemented in Lark interface. The dataset presented here shows the results of the study that compared the impact of these three sky spectrum models on accuracy of Lark simulation tools for prediction of IIL responses.