Evaluation of 24 models of reference evapotranspiration in different climates of Iran

Document Type : Research Article


zabol university


There are various methods for estimating evapotranspiration, in which the performance of these equations varies in different climatic conditions. The purpose of this study is investigate different methods of evapotranspiration of reference plant in different climates of Iran and validate these methods by FAO-Penman-Monteith method. For this, 30-year weather data (1988-2017) were used in nine cities (Shahrekord, Urmia, Mashhad, Zahedan, Bandar Abbas, Ahvaz, Gorgan, Rasht and Sari). Initially, evapotranspiration was obtained by the FAO-Penman-Monteith method on a daily basis. Then reference evapotranspiration values were calculated with 24 other methods. Using RMSE, (MAE), (MR) and (PE) with the method FAO-Penman-Monteith. The results showed that in cold and semiarid, cold, moderate, warm and dry, cold and dry, warm and humid conditions, there were Urmia, Shahrekord, Zahedan, Mashhad and Ahwaz, modified Makking models, in warm and humid climate of Bandar Abbas, respectively. The Voluntzas model and in the Mediterranean, semi-wet and humid climates including Gorgan, Sari and Rasht, the Druggerz and Allen model had a better and closer estimate by the FAO-Penman-Monteith method.Regarding the scores given to each method based on the MAE and RMSE evaluation index, modified Makking models, Derrgger and Allen, Valiantzas and Hargreaves Samani and based on the index PE models and Reynolds and Allen, McQueen modified, Valiantzas and Hargreaves Samani were selected as superior models.


Main Subjects

[1].Gundekar H. G. Khodke U. M, Sarkar S. Evaluation of pan coefficient for reference crop evapotranspiration for semi-arid region. Irrigation Science. 2008; 26: 169-175.
[2].Alizadeh A, Kamali GH, Khanjani M. J. Air and Climatology. Estimation of Evapotranspiration Estimation Methods in Arid Regions of Iran, Geographical Research Magazine,2004; 105: 73-97. [Persian]
[3].Tabari H. Evaluation of reference crop evapotranspiration equations in various climates. Water resources management,2010; 24(10):2311-2337. [Persian]
[4].Azhar A.H, Perera B.J.C. Evaluation of reference evapotranspiration estimation methods under Southeast Australian conditions. Journal of Irrigation and Drainage Engineering. 2010; 137(5):.268-279.
[5].Mehdi Zadeh S, Rakhshani F, Bahmanesh J, Delir Hassannia R. Analysis of the Accuracy of Five Different Models of Valiantzas's Relationship in the Estimation of Reference Evapotranspiration. Irrigation Science and Engineering,2017; 41 (3): 132-119. [Persian]
[6].Namdarian K, Naseri A.A, Izadpanah Z, Maleki A. Comparison of FAO Penman-Monteith method and Class A evaporation pan with lysimetric data Estimation of evapotranspiration of chickpea in Khorramabad region, Iranian Journal of Cereals Research, 2014;6(1):92-99. [Persian]
[7].Djaman K, Balde A.B, Sow A, Muller B, Irmak S, N’Diaye M.K, Manneh B, Moukoumbi Y.D, Futakuchi K, Saito K. Evaluation of sixteen reference evapotranspiration methods under sahelian conditions in the Senegal River Valley. J. Hydrol. Region. Stud. 2015; 3: 139-159.
[8].Khoshhal J, Zare Abyane H, Joshani A.R, Khazaei M. Evaluation of potential Evapotranspiration methods using FAO pan method in east and southeast the Keshvar watershed. Quarterly of Natural Geographical.2008; 8: 28. 1-16. [Persian]
[9]Sabziparvar A.A, Tabari H. Regional estimation of reference evapotranspiration in arid and semi-arid regions. J. Irrig. Drain. Engin.2010; 136(10): 724-731.
[10].Ghorbani KH, Aligholinia, T, Rasouli Majd N. Evaluating the accuracy of the twenty experimental models of estimation of evapotranspiration of the reference plant for coastal areas in different climates. Water and soil conservation research.2017; 25 (4): 320-307. [Persian]
[11].Djaman K, Irmak S, Kabenge I, Futakuchi K. Evaluation of FAO-56 penman-monteith model with limited data and the valiantzas models for estimating grass-reference evapotranspiration in Sahelian conditions. Journal of Irrigation and Drainage Engineering, 2016; 142(11):.04016044.
[12].Irmak S, Irmak A, Allen R.G, Jones, J.W. Solar and net radiation-based equations to estimate reference evapotranspiration in humid climates. Journal of Irrigation and Drainage Engineering.2003; 129(5): 336-347.
[13]. Trajkovic S, Kolakovic S. Evaluation of reference evapotranspiration equations under humid conditions. Water Resources Management,2009; 23(14) : 3057-3067.
[14].Kisi O. Comparison of different empirical methods for estimating daily reference evapotranspiration in Mediterranean climate. Journal of Irrigation and Drainage Engineering,2013; 140(1),2655-2677.
 [15].Droogers P. Allen R.G. Estimating reference evapotranspiration under inaccurate data conditions. Irrigation and Drainage Systems, 2002; 16(1): 33-45.
[16].Rauf M, Azizi Makar J. Evaluation of Eighteen Model of Reference Evapotranspiration in Ardabil Plain. Water and soil conservation research.2017; 24 (6): 240-227. [Persian]
[17].Temesgen B., Eching S, Davidoff B. Frame K. Comparison of some reference Evapotranspiration equations for California, Journal of Irrigation and Drainage Engineering. 2005; 131(1): 73-84.
Volume 6, Issue 3
September 2019
Pages 611-622
  • Receive Date: 09 February 2019
  • Revise Date: 03 June 2019
  • Accept Date: 03 June 2019
  • First Publish Date: 23 September 2019