Comparative analysis of 31 reference evapotranspiration methods under humid conditions

• Published in: Irrigation science Vol. 31; no. 2; pp. 107 - 117
• Main Authors: Tabari, Hossein, Grismer, Mark E., Trajkovic, Slavisa
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.03.2013; Springer Nature B.V
• Subjects: Agriculture; Air temperature; Aquatic Pollution; Biomedical and Life Sciences; Climate Change; Comparative analysis; Developing countries; Environment; Evaporation; Evapotranspiration; Humid climates; Humidity; Irrigation; LDCs; Life Sciences; Mass transfer; Original Paper; Pan evaporation; Solar radiation; Sustainable Development; Waste Water Technology; Water Industry/Water Technologies; Water Management; Water Pollution Control; Iran; Mean Bias Error; Hargreaves Equation; Root Mean Square Error; Extraterrestrial Radiation; Thornthwaite Equation
• ISSN: 0342-7188; 1432-1319
• DOI: 10.1007/s00271-011-0295-z

Evaluation of simple reference evapotranspiration (ET o ) methods has received considerable attention in developing countries where the weather data needed to estimate ET o by the Penman–Monteith FAO 56 (PMF-56) model are often incomplete and/or not available. In this study, eight pan evaporation-based, seven temperature-based, four radiation-based and ten mass transfer-based methods were evaluated against the PMF-56 model in the humid climate of Iran, and the best and worst methods were selected from each group. In addition, two radiation-based methods for estimating ET o were derived using air temperature and solar radiation data based on the PMF-56 model as a reference. Among pan evaporation-based and temperature-based methods, the Snyder and Blaney–Criddle methods yielded the best ET o estimates. The ET o values obtained from the radiation-based equations developed here were better than those estimated by existing radiation-based methods. The Romanenko equation was the best model in estimating ET o among the mass transfer-based methods. Cross-comparison of the 31 tested methods showed that the five best methods as compared with the PMF-56 model were: the two radiation-based equations developed here, the temperature-based Blaney–Criddle and Hargreves-M4 equations and the Snyder pan evaporation-based equation.