Abstract
Five ETo estimation methods viz. Hargreaves (HAR), modified Hargreaves (MHG), FAO-Radiation (RAD), reduced-set Penman–Monteith (RPM), combination method FAO–Penman with wind functions of Watts & Hancock (W&H) were evaluated at eight semi-arid stations in the Indus Basin Irrigation Area (IBIA) of Pakistan. Penman–Monteith (P_M) method was used as base method for evaluation/calibration of those methods. At all eight stations except two (Lahore and Bahawalpur), four out of five methods namely W&H, RAD, MHG, and HAR exhibited strong tendency to overestimate ETo estimates; at Lahore, RAD method under-estimated ETo by 27 %, and at Bahawalpur HAR by 6 %. Overestimation ranges observed were: W&H (9–25 %), RAD (5–42 %), MHG (14–73 %) and HAR (11–45 %). At all eight stations except Jhelum and D.I. Khan, RPM method underestimated ETo by 1–12 %; overestimation at D.I. Khan was 1 % against Jhelum where it was 0 %. This aspect highlighted the variant nature of ETo methods in terms of daily ETo estimates at different locations. At Sialkot, D.I. Khan and Khanpur, RPM method showed excellent performance with top rank; and being ahead of W&H combination method at those stations indicated its effectiveness that how a less data requiring method, if calibrated, could perform even better than a physically based combination method. The RPM method is useful where some of the climatic data are missing, and should be preferred to an alternative ETo calculation procedure, requiring only limited meteorological parameters. To be consistent with FAO recommendations, the global use of P_M method is upheld if the required climatic data are available.
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References
Azhar A.H., Perera B.J.C.: Evaluation of reference evapotranspiration estimation methods under Southeast Australian conditions. J. Irrig. Drain. Eng. 137(5), 1–12 (2011)
Basharat M., Tariq A.R.: Spatial climate variability and its impact on irrigated hydrology in a canal command. Arab. J. Sci. Eng. 38(3), 507–522 (2013)
Saeed M., Mahmood S.: Application of film hole irrigation on borders for water saving and sunflower production. Arab. J. Sci. Eng. 38(6), 1347–1358 (2013)
Zhang, B.; Yu Liu, Y.; Xu, D.; Zhao, N.; Lei, B.; Ricardo, R.D.; Paredes, P.; Paço, T.A.; Pereira, L.S.: The dual crop coefficient approach to estimate and partitioning evapotranspiration of the winter wheat - summer maize crop sequence in North China Plain. Irri. Sci. (2013). doi:10.1007/s00271-013-0405-1
Doorenbos, J.; Pruitt, W.O.: Guidelines for predicting crop water requirements. FAO Irrig. and Drain. Paper No. 24, (2nd edn.), Rome, Italy (1977)
Allen, R.G.; Pereira, L.S.; Raes, D.; Smith, M.: Crop evapotranspiration guidelines for predicting crop water requirements. FAO Irrig. and Drain. Paper No. 56, Rome, Italy (1998)
Vaughan P.J., Ayars J.E.: Noise reduction methods for weighing lysimeters. J. Irrig. Drain. Eng. 135(2), 235–240 (2009)
Jensen, M.E.; Burman, R.D.; Allen, R.G.: Evapotranspiration and irrigation water requirements, committee on irrigation water requirements. Div. Irrig. Drain. Eng., ASCE, Manual No. 70, New York (1990)
Irmak, A.; Irmak, S.; Martin, D.L.: Reference and crop evapotranspiration in south central Nebraska. I: comparison and analysis of grass and alfalfa-reference evapotranspiration. J. Irrig. Drain. Eng. 134(6), 690–699 (2008)
Azhar, A.H.; Perera, B.J.C.: Planning and operation of irrigations systems: judicial use of limited water resources for enhanced water productivity. VDM Verlag Dr. Muller GmbH & Co. KG, Germany, ISBN: 978-3-639-33101-1, pp. 241 (2011)
Trajkovic S., Kolakovic S.: Estimating reference evapotranspiration using limited data. J. Irrig. Drain. Eng. 135(4), 443–449 (2009)
Todorovic, M.; Karic, B.; Pereira, L.S.: Reference evapotranspiration estimate with limited weather data across a range of Mediterranean climates. J. Hydrol. 481, 166–176 (2013). doi:10.1016/j.jhydrol.2012.12.034
Meyer, W.S.: Standard reference evaporation calculation for inland south eastern Australia, technical memorandum, division of water resources, CSIRO, Griffith, Australia (1994)
Meyer, W.S.; Smith, D.; Shell, G.: Estimating reference crop evaporation and crop evapotranspiration from weather data and crop coefficients. Tech. Memo., Division of Water Resources, CSIRO, Griffith, Australia (1995)
Hussein A.S.A.: Grass ET estimates using Penman-type equations in central Sudan. J. Irrig. Drain. Eng. 125(6), 324–329 (1999)
Pereira, A.R.; Pruitt, W.O.: Adaptation of the Thornwaite scheme for estimating daily reference evapotranspiration. Agric. Water Manag. 66(3), 251–257 (2004)
Lopez-Urrea, R.; de Santa Olalla, F.M.; Moratalla, A.: An evaluation of two hourly reference evapotranspiration equations for semiarid conditions. Agric. Water Manag. 86(3), 277–282 (2006)
Nandagiri L., Kovoor G M.: Performance evaluation of reference evapotranspiration equations across a range of Indian climates. J. Irrig. Drain. Eng. 132(3), 238–249 (2006)
Gavilan, P.; Berengena, J.; Allen, R.G.: Measuring versus estimating net radiation and soil heat flux impact on Penman Monteith reference ET estimates in semiarid regions. Agric. Water Manag. 89(3), 275–286 (2007)
Trajkovic S.: Hargreaves versus penman-monteith under humid conditions. J. Irrig. Drain. Eng. 133(1), 38–42 (2007)
Lovelli, S.; Perniola, M.; Tommaso, T.D.; Ventrella, D.; Moriondo, M.; Amato, M.: Effects of rising atmospheric CO2 on crop evapotranspiration in a Mediterranean area. Agric. Water Manag. 97 (2010), 1287–1292 (2010)
Jabloun M., Sahli A.: Evaluation of FAO-56 methodology for estimating reference evapotranspiration using limited climatic data: application to Tunisia. Agric. Water Manag. 95, 707–715 (2008)
Raziei T., Pereira L.S.: Estimation of ETo with Hargreaves-Samani and FAO-PM temperature methods for a wide range of climates in Iran. Agric. Water Manag. 121, 1–18 (2013)
Popova Z., Kercheva M., Pereira L.S.: Validation of the FAO methodology for computing ETo with missing climatic data. Application to South Bulgaria. Irrig. Drain. ICID. 55(2), 201–215 (2006)
Smith, M.: Report on the expert consultation on revision of FAO methodologies for crop water requirements. Division of Land and Water Development, FAO, Rome, Italy (1992)
Hargreaves G.H., Samani Z.A.: Reference crop evapotranspiration from temperature. J. Appl. Engg. Agric. 1(2), 96–99 (1985)
Hargreaves G.H.: Moisture availability and crop production. Trans. ASAE. 18(5), 980–984 (1975)
Azhar, A.H.: Short Term Planning and Operation of Irrigations Systems. PhD Dissertation, School of the Built Environment, Victoria Univ. of Tech., Melbourne, Australia (2001)
Meek, D.W.; Phene, C.J.: Accuracy of estimated reference crop evapotranspiration. Tech. Note, J. Irrig. Drain. Eng. 117(4), 975–977 (1991)
Watts, P.J.; Hancock, N.H.: Evaporation and potential evaporation—a practical approach for agricultural engineers. In: Proceedings of the Conference on Agricultural Engineering, Bunderberg, pp. 290–297 (1984)
Chiew, F.H.S.; McMahon, T.A.: The applicability of Morton’s and Penman’s evapotranspiration estimates in rainfall-runoff modelling. Water Resour. Bull. Am. Water Resour. Assoc. 27(4), 611–620 (1991)
Monteith J.L.: Evaporation and surface temperature. Q. J. R. Meteo. Soc. 107, 1–27 (1981)
Allen R.G, Jensen M.E., Wright J.L., Burman R.D.: Operational estimates of reference evapotranspiration. Agronomy J. USA. 81, 650–662 (1989)
Berengena, J.; Gavilan, P.: Reference evapotranspiration estimation in a highly advective semiarid environment. J. Irrig. Drain. Eng. 131(2), 147–163 (2005)
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Azhar, A.H., Masood, M., Nabi, G. et al. Performance Evaluation of Reference Evapotranspiration Equations Under Semiarid Pakistani Conditions. Arab J Sci Eng 39, 5509–5520 (2014). https://doi.org/10.1007/s13369-013-0817-5
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DOI: https://doi.org/10.1007/s13369-013-0817-5