DRY diffuse horizontal irradiance data
Derivation of diffuse irradiances
The diffuse irradiances were derived for the DRY 2001-2010 data set (Wang et al. 2012; 2013). This was necessary since DMI currently do not measure diffuse irradiances at their meteorological stations.
At the DTU climate station both diffuse horizontal irradiances and global horizontal irradiances have been measured since 1989. Thus, this data set was analysed to estimate how well the diffuse irradiance best could be derived from the measured global irradiances. Dragsted & Furbo (2012) found the method of Skartveit et al. (1998) to be the best, and this method was chosen for the derivation of diffuse horizontal irradiances at the DRY stations. In the two figures below comparisons of the Skartveit et al. diffuse irradiance fraction model with the measured irradiances are shown. More details on the comparisons performed at DTU can be found in the report by Dragsted & Furbo (2012).
- Dragsted, J. & S. Furbo: "Solar radiation and thermal performance of solar collectors for Denmark," DTU Report R-275, DTU, Kgs. Lyngby, Denmark, 2012.
- Skartveit, A., J. A. Olseth & M. E. Tuft: "An hourly diffuse fraction model with correction for variability and surface albedo," Solar Energy, 1998; 63 (3): 173-183.
- Wang, P. R., M. Scharling & K. P. Nielsen: "2001 - 2010 Design Reference Year for Denmark," beta.dmi.dk/fileadmin/Rapporter/TR/tr12-17.pdf, Technical Report 12-17, DMI, Copenhagen, Denmark, 2012.
- Wang, P. G., M. Scharling, K. P. Nielsen, K. B. Wittchen & C. Kern-Hansen: "2001 - 2010 Danish Design Reference Year - Reference Climate Dataset for Technical Dimensioning in Building, Construction and other Sectors," www.dmi.dk/fileadmin/user_upload/Rapporter/TR/2013/TR13-19.pdf, Technical Report 13-19, DMI, Copenhagen, Denmark, 2013.