Multi-lead ahead prediction model of reference evapotranspiration utilizing ANN with ensemble procedure

Obtaining an accurate estimate of the reference evapotranspiration (ET) can be difficult, especially when there is insufficient data to utilize the Penman-Monteith method. Artificial intelligence-based methods may provide reliable prediction models for several applications in engineering. However, time-series prediction based on artificial neural network (ANN) learning algorithms is fundamentally problematic. For example, the ANN model can experience over-fitting during training and, in consequence, lose its generalization. In this research, several over-fitting procedures have been augmented with the classical ANN model, are proposed. This model was applied to the prediction of the daily ET at Rasht city, located in the north part of Iran, by using the minimum and maximum daily temperature of the region collected from 1975-1988. In addition, three different scenarios have been developed in order to achieve better prediction accuracy. The results showed that the proposed ENN model successfully predicted the daily ET with a significant level of accuracy using only the maximum and minimum temperatures. The model also outperformed the classical ANN method. In addition, the proposed ENN compared with Hargreaves and Samani (Appl Eng Agric 1:96-99, 1985) (HGS) model and showed the ENN provides more accurate prediction for ET. Furthermore, the proposed model could provide relatively good level of accuracy when examined for multi-lead predictions, which could not be afford by HGS model. © 2012 Springer-Verlag Berlin Heidelberg.