This study utilized monthly mean daily values of global solar-radiation and
sunshine duration at 41 locations in Saudi Arabia and developed an empiric
al correlation for the estimation of global solar radiation at locations wh
ere it is not measured. The paper also presents the comparison between the
present correlation and other models developed under different geographical
and varied meteorological conditions. The comparisons are made using stand
ard statistical tests, namely mean bias error (MBE), root mean square error
(RMSE), mean percentage error (MPE), and mean absolute bias error (MABE) t
ests. The errors are calculated using monthly mean daily measured and estim
ated values of global solar radiation at all 41 locations. The study found
that the present correlation produced the best estimates of global solar ra
diation. (C) 1999 Elsevier Science Ltd. All rights reserved.