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Comparative study of some estimation methods of evapotranspiration in the tropical zone: case of the region of Pointe-Noire (Congo)

Author Affiliations

  • 1Laboratory of Mechanics Energy and Engineering, Higher National Polytechnics School, Marien Ngouabi University, Brazzaville, Congo
  • 2Laboratory of Mechanics Energy and Engineering, Higher National Polytechnics School, Marien Ngouabi University, Brazzaville, Congo and Department of Exact Sciences, Higher Teacher′s Training School, Marien Ngouabi University, Brazzaville, Congo
  • 3Laboratory of Mechanics Energy and Engineering, Higher National Polytechnics School, Marien Ngouabi University, Brazzaville, Congo

Int. Res. J. Environment Sci., Volume 8, Issue (3), Pages 39-52, July,22 (2019)


Sustainable management of water resources needs a perfect command of the terms of the hydrological balance among them evapotranspiration. This work deals with the comparison of some methods assessing potential evapotranspiration in the tropical zone. It is made using climatic data (temperature, rainfall, relative humidity, sunshine duration, wind speed and Piche evaporation) collected during the period 1990 to 2016 at Pointe-Noire airport in the south-west of Republic of Congo. The results show that, on the monthly scale, the values of potential evapotranspiration (ETP) obtained by the Penman-Monteith method, are closes to those obtained with the measured Piche evaporation. However, during the dry season (August-September), this method of calculation overestimates potential evapotranspiration up to 27.4%. Moreover, the application of the different approaches for estimating the annual ETP, highlights that the Penman-Monteith method, leads also to a better estimate of this climatic component. Nevertheless, this method overestimates Piche ETP in the year 1992, with a relative deviation up to 40.5%.


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