Open Access


Research Article

Main Article Content

Hussein Ilaibi Zamil Al-Sudanicorresponding author


The hydrology section is divided into two main components, surface and groundwater. One of the most important outcomes in the water balance equation for any natural area or water body is Evapotranspiration and it is also a crucial component of the hydrologic cycle. Prediction of monthly evapotranspiration can be obtained depending on observed monthly average temperatures at a meteorological station in each year. Calculating of water balance in Iraq depending on meteorological data and Thornthwaite method was the aim of this research. Results of corrected potential evapotranspiration (PEc) obtained from applying _Thornthwaite formula_ were compared with annual and monthly rainfall in thirty two meteorological station in order to estimate actual evapotranspiration (AE). The results showed that the annual summation of rainfall increased from south west towards north east according to the increasing ratio of rainfall due to the impact of Mediterranean climate condition on Iraq. Actual evapotranspiration depends directly on water excess during calculating water balance. Water surplus contour map indicates increased values towards north-east direction of Iraq, where water surplus depends directly on both rainfall and actual evapotranspiration.

meteorological water balance, thornthwaite formula, evapotranspiration, Iraq

Article Details

How to Cite
Al-Sudani, H. (2020). Calculation of meteorological water balance in Iraq. Resources Environment and Information Engineering, 2(1), 84-89.


  1. Subedi A and Ch´avez JL. Crop Evapotranspiration (ET) Estimation Models: A Review and Discussion of the Applicability and Limitations of ET Methods. Journal of Agriculture Science, 2015, 7(6).
  2. Al-Sudani HIZ. Calculating of Groundwater Recharge using Meteorological Water Balance and Water level Fluctuation in Khan Al-Baghdadi Area. Iraq Journal Science, 2018, 59(1B): 349-359.
  3. Unesco. Scientific framework of world water balance. Technical papers in hydrology, 1971, (7): 27.
  4. Sokolov AA and Chapman TG. Methods for water balance computations, an international guide for research and practice. UNESCO press. Paris. 1974.
  5. Al-Sudani HIZ. Hyrogeological System of Debagah Basin in North of Iraq, Ph.D. Thesis, University of Baghdad, Iraq. 2003.
  6. Domemico PA and Schwartz FW. Physical and chemical hydrogeology. John Wiely and Sons. Inc., New York. 1998.
  7. Al-Sudani HIZ. Study of Morphometric properties and Water Balance using Thornthwaite method in Khanaqin Basin, East of Iraq. Journal of University of Babylon, Engineering Sciences, 2018, 26(3): 165-175.
  8. Al-Sudani HIZ. Temperature – Potential Evapotranspiration Relationship in Iraq Using Thornthwaite Method. Journal of University of Babylon, Engineering Sciences, 2019, 27(1):16-25.
  9. Al-Sudani HIZ. Derivation Mathematical Equations for Future Calculation of Potential Evapotranspiration in Iraq, a Review of Application of Thornthwaite Evapotranspiration. Iraqi Journal of Science, 2019, 60(5): 1037-1048.
  10. Henderson-Sellers A and McGuffie K. The Future of the World’s Climate. Henderson-Sellers, A. and McGuffie, K. (eds), Second Edition. Elsevier, Boston, 2012.
  11. Vangelis H, Tigkas D and Tsakiris G. The effect of PET method on reconnaissance drought index (RDI) calculation. Journal of Arid Environments, 2013, 88: 130–140.
  12. Al-Sudani HIZ. Rainfall Returns Periods in Iraq. Journal of University of Babylon, Engineering Sciences, 2019, 27(2): 1-9.
  13. Al-Shamma A, Taqa ES and Saeed MAH. Water Balance of North Erbil Basin. Iraqi Journal of Science, 2007, 48(1): 124-134.
  14. Al-Sudani HIZ. Groundwater system of Dibdibba sandstone aquifer in south of Iraq. Applied Water Science. 2019, 9(4): 1-11.
  15. Al-Sudani HIZ. Estimation of Water Balance in Iraq using Meteorological Data. International Journal of Recent Engineering Science, 2019, 6(5): 8-13.
  16. Al-Sudani HIZ. Derivation mathematical equations to estimate water surplus and groundwater recharge in Iraq. Applied Water Science, 2020, 10(4): 1-11.
  17. Iraqi meteorological Organization and Seismology. Meteorological data of (32) meteorological station for different periods. Ministry of Transportation. Baghdad. Iraq. 2015.
  18. Thornthwaite CW. An Approach toward a Relation Classification of Climate. Geographical Review. Elsevier, Amsterdam, 1948, 32(55): 3-30.