Validation and calibration of FAO WaPOR product (actual evapotranspiration) in Iran using in-situ measurements

Document Type : Original Article


1 Water Resource Department, Water Research Institute of Ministry of Energy

2 Water Research Institute of Ministry of Energy, Iran

3 Water Research Institute of Ministry of Energy, Tehran, Iran


Estimation of actual evapotranspiration (ETa) in the scales of basin and field is one of the essential information for water resources allocation. Although estimating actual evapotranspiration has encounter with several restrictions (e.g., spatially, temporally and costly), but satellite images data can overcome these limitations usually. In this regard, the objectives of present paper are: a) evaluation and validation of WaPOR ETa product using Scintillometer instrument and, b) estimation of ETa over several land use regions over the Zayanderoud basin. Based on obtained results, MAE, RMSE, MAPE and R are equal to 2.14 (mm for 10 days), 2.55 (mm for 10 days), and 5.50 and 0.97 respectively which represent the appropriateness of WaPOR ETa data in comparison with Scintillometer. Also, the analysis of WaPOR product in different land-used showed that, the maximum amount of actual ETa has occurred in dual crops (513 mm), orchards (387 mm), spring crops (272 mm), autumnal crops (271 mm), dry farming (112 mm) and rangelands (83 mm) respectively. Also the results show that in rice fields, 992 mm fresh water lost in the form of ETa which is considered dramatically due to the climate and water resources of selected basin and its relevance challenges.


Main Subjects

Allen RG, Pereira LS, Raes D and Smith M (1998) Crop evapotranspiration-Guidelines for computing crop water requirements-FAO. Irrigation and drainage paper 56 FAO Rome 300:6541
Allen RG, Tasumi M, Morse A and Trezza R (2005) A Landsat-based energy balance and evapotrans-piration model in Western US water rights regulation and planning. Irrigation and Drainage Systems 19:251-268
Allen RG, Tasumi M and Trezza R (2007) Satellite-based energy balance for mapping evapotranspiration with internalized calibration (METRIC)-Model. Journal of Irrigation and Drainage Engineering 133:380-394
Bagheri M (2013) Assessment of remote sensing technique for estimation of water balance components in basin scale emphasizing on net roundwater exploitationa case study on Urmia lake basin. Tarbiat Modares University, 250p‎ (In Persian)
Bastiaanssen W, Cheema M, Immerzeel W, Miltenburg I and Pelgrum H (2012) Surface energy balance and actual evapotranspiration of the transboundary Indus Basin estimated from satellite measurements and the ETLook model. Water Resources Research 48:100-120
Bastiaanssen W, Menenti M, Feddes R and Holtslag A (1998) A remote sensing surface energy balance algorithm for land (SEBAL) 1 Formulation. Journal of Hydrology 212:198-212
Chong H and Sunding D (2006) Water markets and trading. Annual Review of Environment and Resources 31:239-264
Coe M, Cumming D and Phillipson J (1976) Biomass and production of large African herbivores in relation to rainfall and primary production. Oecologia 22:341-354
Colmer TD and Barton L (2017) A review of warm-season turfgrass evapotranspiration responses to deficit irrigation and drought resistance. Crop Science 57:98-110
Evans RG and Sadler EJ (2008) Methods and technologies to improve efficiency of water use. Water Resources Research 44:151-163
Fao (2008) Food and agriculture organization of the united nations. Aquastat Database  from Water Report 34:220-232
Foster S, Evans R and Escolero O (2015) The groundwater management plan:in praise of a neglected ‘tool of our trade’. Hydrogeology Journal 23:847-850
French AN, Hunsaker DJ and Thorp KR (2015) Remote sensing of evapotranspiration over cotton using the TSEB and METRIC energy balance models. Remote Sensing of Environment 158:281-294
Ghamarnia H, Gholamian SM and Kamali N (2016) Estimating of crop coefficient and actual evapotranspiration of corn using LANDSAT8 Images (case study:Sarab Nilufar plain in Kermanshah). Journal of Iran-Water Resources Research (IR-WRR) 12:93-107 (In Persian)
Grafton RQ, Chu HL, Stewardson M and Kompas T (2011) Optimal dynamic water allocation:irrigation extractions and environmental tradeoffs in the Murray River Australia. Water Resources Research 47:86-97
Hartogensis O, De Bruin H and Van De Wiel B (2002) Displaced-beam small aperture scintillometer test Part II:CASES-99 stable boundary-layer experiment. Boundary-Layer Meteorology 105:149-176
Hemakumara H, Chandrapala L and Moene AF (2003) Evapotranspiration fluxes over mixed vegetation areas measured from large aperture scintillometer. Agricultural Water Management 58:109-122
Hill R and Ochs G (1978) Fine calibration of large-aperture optical scintillometers and an optical estimate of inner scale of turbulence. Applied Optics 17:3608-3612
Jeyaseelan A (2003) Droughts & floods assessment and monitoring using remote sensing and GIS. Satellite remote sensing and GIS applications in agricultural meteorology:291
Khojee AR, Zarkesh MMK, Arasteh PD, Moridi A and Mohammadi RA (2016) Sensitivity analysis of calculated evapotranspiration using daily energy balance model and comparing it with SEBAL model. Journal of Iran-Water Resources Research (IR-WRR) 12:18-28 (In Persian)
Kohsiek W, Meijninger W, Moene A, Heusinkveld B, Hartogensis O, Hillen W and De Bruin H (2002) An extra large aperture scintillometer for long range applications. Boundary-layer meteorology 105:119-127
Liaqat UW and Choi M (2017) Accuracy comparison of remotely sensed evapotranspiration products and their associated water stress footprints under different land cover types in Korean peninsula. Journal of Cleaner Production 155:93-104
Lorenz DJ, Otkin JA, Svoboda M, Hain CR, Anderson MC and Zhong Y (2017) Predicting US drought monitor states using precipitation soil moisture and evapotranspiration anomalies part I:Development of a nondiscrete USDM index. Journal of Hydrometeorology 18:1943-1962
Meijninger W, Beyrich F, Lüdi A, Kohsiek W and Bruin HD (2006) Scintillometer-based turbulent fluxes of sensible and latent heat over a heterogeneous land surface-a contribution to LITFASS-2003. Boundary-layer meteorology 121:89-110
Monteith JL (1965) Evaporation and environment Symp Soc Exp Biol p 4
Qureshi ME, Grafton RQ, Kirby M and Hanjra MA (2011) Understanding irrigation water use efficiency at different scales for better policy reform:a case study of the Murray-Darling Basin. Australia Water Policy 13:1-17
Ochs G and Wang T-I (1978) Finite aperture optical scintillometer for profiling wind and Cn2. Applied Optics 17:3774-3778
Olivera-Guerra LE, Mattar C, Santamaría-Artigas A, Durán-Alarcón C and Fuster R (2013) A first evaluation of an operational method (SSEBop) to estimate Actual Evapotranspiration by using MODIS data over the semi-arid region of Chile. 4th International Symposium on Recent Advances in Quantitative
Papadavid G, Hadjimitsis DG, Toulios L and Michaelides S (2013) A modified SEBAL modeling approach for estimating crop evapotranspiration in semi-arid conditions. Water Resources Management 27:3493-3506
Rahimpour M (2015) Trends assessment of changes in water budget components and land use of Lake Urmia (Iran) and Lake Van (Turkey) basins using remote sensed data. Tarbiat Moodares University (In Persian)
Rodell M, Beaudoing HK, L’ecuyer TS, Olson WS, Famiglietti JS, Houser PR, Adler R, Bosilovich MG, Clayson CA and Chambers D (2015) The observed state of the water cycle in the early twenty-first century. Journal of Climate 28:82-98
Senay GB, Budde M, Verdin JP and Melesse AM (2007) A coupled remote sensing and simplified surface energy balance approach to estimate actual evapotranspiration from irrigated fields. Sensors 7:979-1000
Sima S and Tajrishi M (2015) Estimation of Urmia lake evaporation using remote sensing data. Journal of Iran-Water Resources Research (IR-WRR) 11:32-48 (In Persian)
Su Z (2002) The Surface Energy Balance System (SEBS) for estimation of turbulent heat fluxes. Hydrology and Earth System Sciences 6:85-100
Wagle P, Bhattarai N, Gowda PH and Kakani VG (2017) Performance of five surface energy balance models for estimating daily evapotranspiration in high biomass sorghum. ISPRS Journal of Photogrammetry and Remote Sensing 128:192-203
Wang T-I, Ochs G and Clifford S (1978) A saturation-resistant optical scintillometer to measure C 2 n. JOSA 68:334-338
Wesely ML (1976) The combined effect of temperature and humidity fluctuations on refractive index. Journal of Applied Meteorology 15:43-49
Wu B, Jiang L, Yan N, Perry C and Zeng H (2014) Basin-wide evapotranspiration management:concept and practical application in Hai basin China agricultural. Water Management 145:145-153
Yang Y, Anderson M, Gao F, Hain C, Kustas W, Noormets A, Sun G, Wynne R and Thomas V (2017) Evaluation of drought impact on evapotranspiration (et) over a forested landscape in North Carolina USA using daily Landsat-scale ET. Geophysical Research 38:13-27