Predictability of Streamflow Processes of the Yellow River

Understanding the predictability of a streamflow process is important for making decision for flood control and water management. However not much attention has been paid to the predictability study of streamflow processes so far. Predictability may be broken down into two categories: (1) model predictability and (2) potential predictability. The widely used model performance measure, coefficient of efficiency (CE), can act as a measure of model predictability for stationary series, however, it could be misleading about the model performance when being applied to seasonal processes which have seasonal mean values. Therefore, an adjusted coefficient of efficiency (ACE) is proposed for evaluating model predictability for seasonal time series. The model predictability of two daily river flow processes of the upper and middle Yellow River are studied based on linear ARMA models and measured in terms of ACE.