DEVELOPMENT OF A SIMPLIFIED ESTIMATION METHOD FOR SPECTRAL DIFFUSE SOLAR IRRADIANCE INCLUDING ULTRAVIOLET, VISIBLE, AND NEAR-INFRARED IRRADIANCE Research on a simplified spectral solar irradiance estimation method under all weather conditions

In this paper, a simplified regression equation that estimates spectral diffuse solar irradiance between 0.3 and 2.5 μm under all-weather conditions from broadband diffuse solar irradiance, is presented. Furthermore, three kinds of correction equations to correct the regression equation are created using diffuse fraction, air-mass, and precipitable water. Using these equations, we calculated the all-weather spectral diffuse solar irradiance and compared it with the measured values. It was found that average of root mean square error for the estimated spectral diffuse solar irradiance between 0.3 and 2.5 μm decreased by 45.5% due to the effect of using all correction equations. © 2023 Architectural Institute of Japan. All rights reserved.