Initially, the training process was applied, and the ANN model
was obtained to get a predictive equation based on data from the
1980e2009 period. Following the network training process and the
evaluation of model performance in the training period, the model
is tested over a short period of data which is not included in the
training process. In this case, the test was performed over the
period of 2010e2011. In this test process, the evaluation of method
performance is measured by R2 parameter which is defined as.