Table of Contents
ISRN Renewable Energy
Volume 2012 (2012), Article ID 328237, 10 pages
http://dx.doi.org/10.5402/2012/328237
Research Article

Prediction of Global Solar Radiation in Abu Dhabi

Electrical Engineering Department, United Arab Emirates University, P.O. Box 71555, Al Ain, UAE

Received 27 November 2011; Accepted 28 December 2011

Academic Editors: H. K. Ozturk and P. Tsilingiris

Copyright Β© 2012 Ali Assi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Mathematical expressions have been employed to estimate global solar radiation on horizontal from relative sunshine duration for two weather stations in the United Arab Emirates (UAE), which are Abu Dhabi and Al Ain. These expressions include the original Angstrom-Prescott regression function (linear), quadratic function, third-order function, single-term exponential function, power function, logarithmic, and linear-logarithmic function. The predicted values were compared to the measured values using number of statistical methods to validate the goodness of the fits, such as residual analysis and goodness of fit statistics. All the used mathematical models performed generally well in both cities of Abu Dhabi and Al Ain, with all values of the coefficient of determination (𝑅2) higher than 75%. Specifically, the linear Angstrom-Prescott model estimated the average monthly global radiation on horizontal best for the city of Abu Dhabi, providing the second lowest mean absolute percentage error (MAPE) of 1.89% and the highest value of 𝑅2, which is approximately 94%, while the third-order model proved to be the best estimator for the city of Al Ain, providing the lowest MAPE value (3.06%) and a corresponding 𝑅2 of 83%.