Climatological values of the direct and the diffuse solar irradiation on the horizontal surface at De Bilt are calculated.
A data set of about 24 years on 11 different orientations in Cabauw is used to relate the diffuse solar irradiation on the orientations to the diffuse solar irradiation on the horizontal surface.
These relations were used together with the climatological diffuse solar irradiation on the horizontal surface and sunshine climatology to calculate monthly climatological diffuse radiations on these orientations. Monthly climatological values of the direct irradiation on each orientation were calculated assuming an even distribution of the sunshine over the day and a constant Linke turbidity factor for each month during sunshine. The groundreflected Irradiation on the orientations was calculated for an albedo of 0.2. Tables show halfmonthly climatological values for the global, the direct, the diffuse and the groundreflected daily irradiation on the following orientations at De Bilt:
horizontal, east 90°, south 90°, west 90°, north 90°, eans 45°, southeast 45°, south 45°, south-west 45°, west 45°, south 22,5 and south
W.H. Slob. Climatological valus of solar irradiation on the horizontal and several inclined surfaces at De Bilt
KNMI number: WR-82-07, Year: 1982, Pages: 46