Empirical models for estimating global solar radiation over the Ashanti Region of Ghana

Abstract
Te performances of both sunshine and air temperature dependent models for the estimation of global solar radiation (GSR) over Ghana and other tropical regions were evaluated and a comparison assessment of the models was carried out using measured GSR at Owabi (6∘45�0��N, 1∘43�0��W) in the Ashanti region of Ghana. Furthermore, an empirical model which also uses sunshine hours and air temperature measurements from the study site and its environs was proposed. Te results showed that all the models could predict very well the pattern of the measured monthly daily mean GSR for the entire period of the study. However, most of the selected models overestimated the measured GSR, except in April and November, where the empirical model using air temperature measurements underestimated the measured GSR. Nevertheless, a very good agreement was found between the measured radiations and the proposed models with a coefcient of determination within the range 0.88–0.96. Te results revealed that the proposed models using sunshine hours and air temperature had the smallest values of MBE, MPE, and RMSE of −0.0102, 0.0585, and 0.0338 and −0.2973, 1.7075, and 0.9859, respectively.
Description
An article published by Journal of Solar Energy and available at http://dx.doi.org/10.1155/2014/897970
Keywords
Citation
Journal of Solar Energy Volume 2014, Article ID 897970, 6 pages
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