GLOBAL SOLAR RADIATION IN TWO TUNISIAN CITIES: COMPARISON OF PREDICTION AND MEASURED DATA

摘要

In this paper, we have studied the solarradiation data available at two meteorologicalstations located in the south of Tunisia.Measurements of global solar radiation onhorizontal surface are compared to predictionsmade by different methods. The first method isbased on Angstr?m-Prescott formula whichcorrelates relative global solar radiation H/H0 tocorresponding relative duration of bright sunshineSS/SS0. The second method, a model due toMechlouch et al., uses cloud cover N, the hours ofthe day t and the quantum of the year q. The thirdmethod, an empirical relation due to Sivkov, usesthe monthly sunshine duration nm and the noonaltitude of the sun h.The models are compared and tested on the basis ofstatistical error tests (MBE, RMSE, MPE and R2)and the results are presented.