Modeling monthly potential evapotranspiration using Genetic Programming in ‎Sistan va baluchestan province

Evapotranspiration is one of the parameters that have special importance in various areas of agriculture and water resources management also for definition of future policies estimating of it, is required. In this study for studying evapotranspiration behaviors, Genetic programming is applied. Four synoptic stations in Zahedan, Zabol, Iranshahr and Chabahar for determining structure of models is used. Inputs are the time series of evapotranspiration that calculated from penman- mantis and regulated in 16 individually dilatory patterns. Reason of this research is to determine mathematical models for estimating evapotranspiration and studying assessment of Genetic programming at estimating evapotranspiration. 80% of data are used in train section to develop models and 20% are used for testing and validating models and calculating the accuracy of them. Results showed that Genetic programming is suitable approach for modeling evapotranspiration. Also the best model with 1.03 RMSE and 0.96 R2 in test section is obtained to Zabol station.