A review of regression models employed for predicting diffuse solar radiation in North-Western Africa

Julie C. Ogbulezie, Ogri James Ushie, Samuel Chukwujindu Nwokolo


The knowledge of diffuse solar radiation (Hd) is of almost importance for determining the gross primary productivity, net ecosystem, exchange of carbon dioxide, light use efficiency and changing colour of the sky. However, routine measurement of Hd is not available in most locations in North-Western Africa. During the past 36 years in order to predict Hd in the horizontal surface on hourly, daily and monthly mean basis, several regression models have been developed for numerous locations in North-Western Africa. As a result, several input parameters have been utilized and different functional forms applied. The regression models so far utilized were classified into six main categories and presented based on the input parameters applied. The models were further reclassified into numerous main groups and finally represented according to their developing year. In general, 188 regression models, 33 functional forms and 20 groups were reported in literature for predicting Hd in North-Western Africa. The regression and soft computing models developed within North-Western Africa and across the globe were examined in order to determine the best technique of prediction. The result revealed that soft computing models are more suitable for predicting Hd in North-Western Africa and across the globe. 

Citation: Ogbulezie, J., Ushie, O., and Nwokolo, S. (2017). A review of regression models employed for predicting diffuse solar radiation in North-Western Africa. Trends in Renewable Energy, 3(2), 160-206. DOI: 10.17737/tre.2017.3.2.0042


Diffuse solar radiation; Regression models; Classification; Functional forms; North-Western Africa

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DOI: http://dx.doi.org/10.17737/tre.2017.3.2.0042


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