Statistical Modelling of Global Solar Radiation on Horizontal Surface Using Monthly Means Daily Sunshine Hours and Some Climatic Variables for Zamfara State, Nigeria

Abstract

In this study, four empirical models on the basis of the linear Angstrom- Prescotte model for predicting monthly mean daily global solar radiation on the horizontal surface were developed, correlating solar radiation to climatic parameters of sunshine hours, temperature and relative humidity. The models were used to predict Global solar radiation, an average solar radiation of 16.9690 Mjm^-2 day^-1  and maximum and a minimum of 19.2647 and 13.5222 C ⁰ were respectively predicted. For validation and the accuracy of the models, statistical coefficient of determination, R², mean percentage error, (MPE), mean bias error, (MBE), and root mean square error (RMSE) were used. The result showed that, model correlating solar radiation with Sunshine hours, temperature and relative humidity gives the best fit for the study location with R²= 83.89%.