Estimation of Global Solar Radiation in Ibadan, Nigeria using Angstrom - Prescott and Glover - Mcculloch’s Model

Abstract

In this study, the data of mean daily bright sunshine hour for Ibadan was obtained from the International Institute of Tropical Agriculture (IITA) at Ibadan. It was used to estimate the monthly mean global solar radiation for Ibadan (latitude and longitude ). The data considered were for a period of 2008 to 2012. Angstrom-Prescott, and Glover & McCulloch’s Models were then used to estimate the mean monthly global solar radiation at Ibadan based on the monthly mean bright sunshine hour data of Ibadan. A new sunshine based model is also proposed to estimate global solar radiation at Ibadan for a period of five years (2008 – 2012). The performance of the models are evaluated by some statistical analysis like mean bias errors, root mean square error, mean percentage error, Nash- Sutcliffe error and coefficient of correlation in order to know the most suitable model. It was discovered that the month of August is the least amount of measured global solar radiation averaged for five years (2008 – 2012) at Ibadan is 9.77kW/m2. The most suitable model for Ibadan is Model 2 (Glover & McCulloch’s Model). The results obtained were validated with data of monthly mean global solar radiation data for Ibadan, obtained from the International Institute of Tropical Agriculture, Ibadan