すべての天空状態の天空放射輝度分布を示す数式と鉛直面日射量の推定 : 天空放射輝度分布のモデル化に関する研究(その2)

抄録

The aim of this study is to propose a sky radiance distribution model for all sky conditions from clear sky to overcast sky. In the previous paper, the indices to estimate sky radiance distributions were examined based on the measurement data in Tokyo and Fukuoka by IDMP of CIE. The normalized global irradiance and cloudless index were selected as indices to estimate sky radiance distributions. This paper proposes a numerical equation named All Sky Model - R to show sky radiance distributions for all sky conditions as functions of these indices. The All Sky Model - R was compared with the measurement values of sky radiance distributions, and its high accuracy was confirmed. Moreover, the vertical global irradiances from the estimation of the All Sky Model - R, Isotropic model and Perez model were compared with the measurement values. It was confirmed that the All Sky Model - R gives smallest RMSE values and reproduces actual phenomenon of the sky accurately.