A FURTHER COMPARISON AND DISCUSSION OF SUNSHINE-BASED MODELS TO ESTIMATE GLOBAL SOLAR-RADIATION

In this paper, five sunshine-based correlations, namely, Benson et al, Gopinathan, Ögelman et al, Zabara and our new quadratic correlation are evaluated in terms of predictive accuracy. The data for 67 stations, ranging in altitude between 3 and 2210 m and in latitude between 20.15 °S and 53.30 °N, have been used. The new solar constant 1367 W m-2 is used in the analysis. The overall results show that the correlations of Benson et al and Gopinathan fall in the second rank and that the difference in estimation errors for the other three is negligibly small. Use of the new quadratic correlation is proposed because of its relatively wider spectrum of values for a and b. © 1990.