Estimating Global Solar Radiation on Horizontal from Sunshine Hours in Abu Dhabi – UAE

Number of mathematical correlations have been used to predict the monthly average global solar radiation on horizontal using the sun hours as an input parameter. The study was carried out on two weather stations in the UAE, which are Abu Dhabi and Al Ain, using a daily weather data recorded for 13 years. The used correlations included the linear Angstrom-Prescott model and its derivations, namely, the second and third order correlations. Moreover, the single term exponential model, logarithmic model, linear logarithmic model and power model were all examined in this work. The performance of the aforementioned correlations as global solar radiation estimators was evaluated by comparing the predicted values with the measured values. Different statistical error tests were employed to examine the accuracy of the mathematical models. In general all fits performed well in both Abu Dhabi and Al Ain, with all giving values of R greater than 81% except for the power model in Al Ain, which produced R of 74%. The linear Angstrom-Prescott model and the third order model performed the best for Abu Dhabi and Al Ain, respectively. Key-Words: Solar energy, global solar radiation, mathematical correlations, regression models, sunshine duration.