Performance of Some Evapotranspiration Equations in an Arid Region


  • Mohammad Mehdi HEYDARI Young Researchers and Elite Club, Kashan Branch, Islamic Azad University, Kashan
  • Ali ABBASI Young Researchers and Elite Club, Kashan Branch, Islamic Azad University, Kashan
  • Morteza HEYDARI Department of Computer Engineering, Ashtian Branch, Islamic Azad University, Ashtian


Qom province, evapotranspiration, statistical indicators, FAO Penman Monteith, Blaney-Criddle, pan evaporation


Estimation of evapotranspiration is necessary for planning, design and irrigation design and water resources management. In order to determine the best method to estimate evapotranspiration using data of Qom synoptic meteorological stations during the years 1987 to 2007 was statistically significant. The FAO Penman Monteith (FAO-56 PM) method has been accepted by many researchers and international institutes as the reference and standard method. Accurate difference methods include Blaney-Criddle, Hargreaves-Samani, Jensen-Haise, Linacre, Rn-based method, Thornthwaite and Turc were applied and then their results were compared with the FAO-56 PM method. In this study, using statistical indicators, the best method to estimate ET0 in Qom province was selected and found to be Blaney-Criddle (RSME = 0.690 mmd-1, MAE = 0.545 mmd-1, D = 0.998). The results indicate that ET0 increases from north to south, west to east in the province. The regression relationship between the mean temperature and FAO-56 PM method and evaporation from the pan were determined. Also comparison of the pan evaporation and monthly values of FAO-56 PM method, coefficient pan (Kp = 0.583) is calculated.



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GR Allen, LS Pereira, D Raes, M Smith. Crop Evapotranspiration-Guidelines for Computing Crop Water Requirements. FAO Irrigation and Drainage Paper 56, FAO, Rome, Italy, 1998, 78-86.

PJ Slabbers. Surface roughness of crops and potential evapotranspiration. J. Hydrol. 1977; 34, 181-91.

C Stefano and V Ferro. Estimation of evapotranspiration by Hargreaves formula and remotely Sensed data in semi-arid Mediterranean areas. J. Agric. Eng. Res. 1997; 68, 189-99.

IP Wu. A Simple evapotranspiration model for Hawaii: The Hargreaves model. Engineer’s Notebook 1997; 106, 1-2.

M García, D Raes, SE Jacobsen and T Michel. Agroclimatic constraints for rainfed agriculture the Bolivian Altiplano. J. Arid. Environ. 2007; 71, 109-21.

J Price. Land surface temperature measurements from the split window channels of the NOAA 7 advanced very high resolution radiometer. J. Geophys. Res. 1984; 89, 7231-7.

WGM Bastiaanssen. SEBAL-based sensible and latent heat fluxes in the irrigated Gediz Basin, Turkey. J. Hydrol. 2000; 229, 87-100.

MM Heydari and M Heydari. Calibration of Hargreaves-Samani equation for estimating reference evapotranspiration in semiarid and arid regions. Arch. Agron. Soil Sci. 2014; 60, 695-713.

MM Heydari and M Heydari. Evaluation of pan coefficient equations for estimating reference crop evapotranspiration in the arid region. Arch. Agron. Soil Sci. 2014; 60, 715-31.

MM Heydari, RN Noushabadi, M Vahedi, A Abbasi and M Heydari. Comparison of evapotranspiration models for estimating reference evapotranspiration in arid environment. Mid. East J. Sci. Res. 2013; 15, 1331-7.

RG Allen, WO Pruitt, JL Wright, TA Howell, F Ventura, R Snyder, D Itenfisu, P Steduto, J Berengena, JB Yrisarry, M Smith, LS Pereira, D Raes, A Perrier, I Alves, I Walter and R Elliott. A recommendation on standardized surface resistance for hourly calculation of reference ET0 by the FAO56 Penmane Monteith method. Agric. Water Manag. 2006; 81, 1-22.

HAR de Bruin and JNM Stricker. Evaporation of grass under non-restricted soil moisture conditions. Hydrol. Sci. 2000; 45, 391-406.

MH Al-Ghobari. Estimation of reference evapotranspiration for southern region of Saudi Arabia. Irrig. Sci. 2000; 19, 81-6.

PS Kashyap and RK Panda. Evaluation of evapotranspiration estimation methods and development of crop coefficients for potato crop in a sub-humid region. Agric. Water Manag. 2001; 50, 9-25.

M Smith. The application of climatic data for planning and management of sustainable rainfed and irrigated crop production. Agric. For. Meteorol. 2000; 103, 99-108.

IA Walter, RG Allen, R Elliott, ME Jensen, D Itenfisu, B Mecham, TA Howell, S Snyder, P Brown, S Echings, T Spofford, M Hattendorf, RH Cuenca, JL Wright and D Martin. ASCE’S standardized reference evapotranspiration equation. In: Proceedings of the 4th National Irrigation Symposium, ASAE, Phoenix, Arizona, USA, 2000, p. 14-6.

KA Adeniran, MF Amodu, MO Amodu and FA Adeniji. Water requirements of some selected crops in Kampe dam irrigation project. Aust. J. Agric. Eng. 2010; 1, 119-25.

MM Heydari, A Abasi, SM Rohani and SMA Hosseini. Correlation study and regression analysis of drinking water quality in Kashan City, Iran. Walailak J. Sci. & Tech. 2013; 10, 315-24.

MM Heydari, A Abbasi and M Heydari. Estimation of Evapotranspiration in Ardestan, Center of Iran. World Appl. Sci. J. 2013b; 21, 230-6.

HF Blaney and WD Criddle. Determining Consumptive Use and Irrigation Water Requirements. Agricultural Research Service Technical Bulletin 1275, United States Department of Agriculture, 1962, p. 59.

GH Hargreaves and ZA Samani. Reference crop evapotranspiration from temperature. Appl. Eng. Agric. 1985; 1, 96-9.

M Jensen and H Haise. Estimating evapotranspiration from solar radiation. J. Irr. Drain. Div. 1963; 89, 15-41.

NJ Rosenberg, BL Blad and SB Verma. Microclimate: The Biological Environment. 2nd ed. John Wiley and Sons, NY, 1983, p. 495.

R Burman and LO Pochop. Evaportion, Evapotranspiration and Climatic Data. Elsevier Science, 1994, p. 278.

S Irmak, A Irmak, RG Allen and JW Jones. Solar and net radiation-based equations to estimate reference evapotranspiration in humid climates. J. Irrig. Drain. Eng. 2003; 129, 336-47.

CW Thornthwaite. An approach toward a rational classification of climate. Geograph. Rev. 1948; 38, 55-94.

L Turc. Estimation of irrigation water requirements, potential evapotranspiration: A simple climatic formula evolved up to date. Ann. Agronomy. 1961; 12, 13-49.

EM Douglas, JM Jacobs, DM Sumner and RL Ray. A comparison of models for estimating potential evapotranspiration for Florida land covers types. J. Hydrol. 2009; 373, 366-76.

M García, D Raes, SE Jacobsen and T Michel. Agroclimatic constraints for rain fed agriculture the Bolivian Altiplano. J. Arid. Environ. 2007; 71, 109-21.

DT Jensen, GH Hargreaves, B Temesgen and RG Allen. Computation of ET0 under non ideal conditions. J. Irrig. Drain. Eng. 1997; 123, 394-400.

TS Lee, MMM Najim and MH Aminul. Estimating evapotranspiration of irrigated rice at the West coast of the Peninsular of Malaysia. J. Appl. Irrig. Sci. 2004; 39,103-17.

OSA Rizaiza and MH Al-Osaimy. A statistical approach for estimating irrigation water usage in western Saudi Arabia. Agric. Water Manag. 1996; 29, 175-85.

M Beyazgul, Y Kayam and F Engelsman. Estimation methods for crop water requirements in the Gediz basin of western Turkey. J. Hydrol. 2000; 229, 19-26.

BA George, BRS Reddy, NS Raghuwanshi and WW Wallender. Decision support system for estimating reference evapotranspiration. J. Irrig. Drain. Eng. 2002; 128, 1-10.

YL Li, JY Cui, TH Zhang and HL Zhao. Measurement of evapotranspiration of irrigated spring wheat and maize in a semi-arid region of north China. Agric. Water Manag. 2003; 61, 1-12.

RB Singandhupe and RR Sethi. Estimation of reference evapotranspiration and crop coefficient in wheat under semi-arid environment in India. Arch. Agron. Soil Sci. 2005; 51, 619-31.

S Chauhan and RK Shrivastava. Performance evaluation of reference evapotranspiration estimation using climate based methods and artificial neural networks. Water Resour. Manag. 2009; 23, 825-37.

B Benli, A Bruggeman, T Oweis and H Ustun. Performance of Penman-Monteith FAO56 in a semiarid highland environment. J. Irrig. Drain. Eng. 2010; 136, 757-65.

OE Mohawesh. Spatio-temporal calibration of Blaney-Criddle equation in arid and semiarid environment. Water Resour. Manag. 2010; 24, 2187-201.

B Mostafazadeh-Fard, M Heidarpour and SE Hashemi. Species factor and evapotranspiration for an Ash (Fraxinus rotundifolia) and Cypress (Cupressus arizonica) in an arid region. Aust. J. Crop Sci. 2009; 3, 71-82.

M Ehteshami, P Najafi and M Sattar. Use of minimum climate information in the estimation of the evapotranspiration reference crop in Isfahan (in Persian). J. Soil Water. 1999; 13, 140-7.

K Shahedi and M Zarei. Assessment methods to estimate the potential evapotranspiration in the province Mazandaran (in Persian). J. Irrig. Water Eng. 2011; 1, 12-21.

RA Farhoodi and AA Imamshamsi. Estimated potential evapotranspiration area of southern Baluchistan (in Persian). Geog. Res. 2000; 39, 105-14.

CJ Phene and RB Campbell. Automating pan evaporation measurements for irrigation control. Agric. Meteor. 1975; 15: 181-91.

G Stanhill. Is the Class A pan evaporationstill the most practical and accurate meteorological method for determining irrigation water requirements. Agric. Meteor. 2002; 112, 233-6.

S Trajkovic. Comparison of radial basis function networks and empirical equations for converting from pan evaporation to reference evapotranspiration. Hydrol. Process. 2009; 23, 874-80.

HG Gundekar, UM Khodke, S Sarkar and RK Rai. Evaluation of pan coefficient for reference crop evapotranspiration for semi-arid region. Irrig Sci. 2008; 26, 169-75.

A Rahimikhoob. An evaluation of common pan coefficient equations to estimate reference evapotranspi-ration in a subtropical climate (north of Iran). Irrig Sci. 2009; 27, 289-96.




How to Cite

HEYDARI, M. M., ABBASI, A., & HEYDARI, M. (2014). Performance of Some Evapotranspiration Equations in an Arid Region. Walailak Journal of Science and Technology (WJST), 12(1), 95–109. Retrieved from



Research Article