The article presents the elaboration of the quasi-global radiation model. This model was used to determine the solar illumination radiation of Slovenia. The solar energy depends mostly on the ...incidence angle defined by astronomical and surface parameters, and on meteorological conditions, especially duration of solar radiation. The surface parameters were calculated from the InSAR DMV 25 interferometric radar digital elevation model. The virtual Sun motion was simulated with equations derived from the astronomical almanac. Shade determination was considered as an important part of the model. If a part of the surface is in the shadow, it receives far less energy than sunny surfaces. Corresponding meteorological parameters were also integrated in the model. All calculations were done for hours and decades (ten-day periods). The annual quasi-global radiation energy was calculated as the sum of all energies over all decades.
