عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Estimating reference crop evapotranspiration (ETo) is necessary for designing irrigation systems, water resources management, yield production and environmental assessments. Different models and methods have been developed in order to predict ETo using time series, including AR, MA and ARIMA. However, Chaos Theory has not been utilized to estimate the ETo till now. In this study, the performance of the mentioned time series models was evaluated for estimating daily ETo in Torbat-e-Heydarieh synoptic station, Khorasan Razavi, during 1991-2000. Results showed that the ARIMA and Chaos Theory estimate the ETo with the same accuracy, so that the correlation coefficients between observed and estimated values for ARIMA and Chaos Theory were 0.895 and 0.894, and RMSE values were 0.585 and 0.611 mm day-1, respectively.