Authors: Wu Ji and Chan Chee Keong
In this work, we firstly check the stationarity of solar radiation series and find it’s non-stationary. To remove the trend lying in it to obtain a stationary series, we apply several detrending models to the series. Then Augement Dickey-Fulle test is used to check the stationarity of the residual series. As a result, the Al-Sadah’s model is proved to be the optimal one. After the detrending, ARMA is applied to do prediction and its performance is compared with linear regression whose performance has been proved to be good. The result shows that after detrending, ARMA can present better performance.