The number of radiation data collection stations is limited due to economic
reasons. Hence, there is a need for the spatially continuous mapping of so
lar radiation by estimation. This paper utilizes a geostatistical technique
for the estimation of solar radiation in Saudi Arabia. This technique incl
udes five steps: (i) data collection, (ii) univariate analysis, (iii) exper
imental variogram calculations and model fitting, (iv) estimation using kri
ging, and (v) plotting contour maps. Variogram models are fitted to measure
d variograms for each month of the year. Estimates were obtained at 1500 gr
id points (30 x 50) between a longitude of 36.58 degrees E and 50.00 degree
s E, and latitude of 17.17 degrees N and 31.33 degrees N for a grid resolut
ion of 55 x 33 km. These values were used to plot the contour maps of solar
radiation for each month of the year. To test the performance of the techn
ique, estimates were obtained at the 41 known locations by systematically e
xcluding one of these points from the known data. The error analysis showed
a maximum mean deviation between measured and estimated values of 0.0037 (
January) and a minimum of 0.0013 (March and October). The mean percent erro
rs were found to vary between a minimum of 0.5% and a maximum of 1.7%. This
technique may be expanded for the spatial estimation of solar radiation on
regional and continental scales. (C) 2000 Published by Elsevier Science Lt
d.