Direct luminous efficacy and atmospheric turbidity—Improving model performance

摘要: Of all the atmospheric constituents, aerosol content is shown to be responsible for greatest variations in direct luminous efficacy. Some clarity brought comparison between Linke's and Angstrom's turbidity coefficients, respectively TL β. Grenier's recent formulation of optical thickness a water free atmosphere presented here simplified expression. Based on these results Dogniaux's illuminance factor, Til, two efficacy models are derived, one which tuned our experimental data. The input parameters air mass, β, vapour version. These perform significantly better than any twelve other found literature when compared 1 yr's measurements from each sites U.S. Switzerland. In both sites, β was derived horizontal visibility estimated nearby airport.