Temperature-Based Feed-Forward Backpropagation Artificial Neural Network For Estimating Reference Crop Evapotranspiration In The Upper West Region

The potential of modeling the FAO Penman-Monteith (FAO-56 PM) method for computing reference crop evapotranspiration (ETo) using feed-forward backpropagation artificial neural networks (FFBANN) with minimal measured climate data such as with the air temperature (maximum and minimum) was investigated using local climatic data from the Wa Meteorological weather station. Three FFBANN models were developed and trained with the Levenberg-Marquardt algorithm and the early stopping approach. These three FFBANN models are temperaturebased models and have the same input variable as the established temperature-based empirical methods; the Hargreaves, Blaney-Criddle and the Thornthwaite methods. A comparative study was carried to see how these FFBANN models performed relative to the other three established temperature-based empirical methods using the FAO-56 PM method as the benchmark. In general, the FFBANN models outperformed these established methods in estimating the ETo and should be preferred where only measured air temperature (maximum and minimum) is the variable available for estimating the reference crop evapotranspiration. Index Terms – Reference crop evapotranspiration, Feed-Forward backpropagation artificial neural network. ————————————————————