dada for "Sky Type Classification in Harbin During Winter"
Description
Sky type classification is significant for the daylighting simulation. As a winter city, the daylight climate of Harbin turns to be distinct from other areas, and there is a need to select the most appropriate sky models for establishing the sky luminance distribution and improving the accuracy of daylight simulations. To identify the closest sky type in Harbin during winter, sky luminance data of 145 sky elements was collected every 10 min from November 1, 2018, to February 28, 2019 by sky scanner. The sky luminance data was compared with the 15 standard sky definitions varying from the overcast sky to clear sky proposed by Commission International de l' Eclairage (CIE), the one with lowest RMSE was selected to be the most appropriate sky type.The Tregenza method was adopted in the present work and a MATLAB code was developed for the whole process. The results showed that clear skies prevail in Harbin during winter with an occurrence of 70.56%. The dominant sky type is type 12 (CIE standard clear sky, low luminance turbidity), with an occurrence of 48.57%, followed by type 11, 10, 8 with the occurrence of 17.67%, 5.81, 5.36%. The sum of the occurrences of these four sky types exceed 77%, which means that they can be regarded as the representative skies of Harbin during winter.