The Impact of some Meteorological Variables on the Estimation of Global Solar Radiation in Kano, North Western, Nigeria

Abstract

This study examines the impact of measured monthly average daily global solar radiation, sunshine duration, wind speed, maximum and minimum temperatures, rainfall, cloud cover and relative humidity parameters on the estimation of global solar radiation during the period of thirty one years (1980 – 2010) for Kano, Nigeria (Latitude 12.03⁰N, Longitude 08.12⁰E and altitude 472.5 m above sea level) using different selected proposed empirical models. The accuracy of the proposed models are tested using statistical indicator; Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE), t – test, correlation coefficient (R) and coefficient of determination (R²). The developed models are based on one variable correlation, two variable correlations, three variable correlations, four variable correlations, five variable correlations and six variable correlations, in each case one or two empirical models has been recommended based on their outstanding performance in line with the statistical test subjected to. The model (Eqn. 36) with the highest values of R and R² and lowest values of MBE, RMSE, MPE and t – test as compared with other developed model is considered the best performing model. It was observed that the newly recommended developed models (Eqns. 13, 17, 21, 26, 27, 31, 35 and 36) can be used for estimating daily values of global solar radiation with higher accuracy and has good adaptability to highly changing climatic conditions for Kano and regions of similar climatic information.

Keywords: global solar radiation, sunshine duration, wind speed, rainfall and coefficient of determination.