IAHS2022-149
https://doi.org/10.5194/iahs2022-149
IAHS-AISH Scientific Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins

Papa Malick Ndiaye1, Ansoumana Bodian1, Serigne Bassirou Diop1, Lamine Diop2, Alain Dezetter3, Andrew Ogilvie4, and Koffi Djaman5
Papa Malick Ndiaye et al.
  • 1Laboratoire Leïdi “Dynamique des Territoires et Développement”, Université Gaston Berger (UGB), Sénégal
  • 2UFR S2ATA Sciences Agronomiques, de l’Aquaculture et des Technologies Alimentaires ; Université Gaston Berger, Saint-Louis BP 234, Sénégal
  • 3HydroSciences Montpellier, University of Montpellier, IRD, CNRS, CC 057, 163 rue Auguste Broussonnet ; 34090 Montpellier, France
  • 4UMR G-EAU, AgroParisTech, Cirad, University of Montpellier, IRD, INRAE, Montpellier SupAgro, 34196 Montpellier, France
  • 5Department of Plant and Environmental Sciences, New Mexico State University, Agricultural Science Center at Farmington, P.O. Box 1018, Farmington, NM 87499, USA

Analysis of reference evapotranspiration (ET0) trends is essential for understanding the impacts of climate change on water resources. Thus, despite the continuous rise in temperatures, a decrease in evapotranspiration is noted in some parts of the world. This contrast is called the "evaporation paradox" and is thought to be related to the variation in wind speed, relative humidity and solar radiation. The objective of this work is to analyze, based on the Reanalysis weather data from the NASA Langley Research Center (LaRC) POWER project, the annual and seasonal trends of ET0 and climate variables at the scale of the Senegal, Gambia and Casamance rivers basins over the period 1984-2019. Mann Kendall's test and Sen slope were used to analyze trends in ET0 and climate variables. Results show that on annual scale, ET0 increases significantly in 32% of the Senegal basin and decreases in less than 1% of it. In contrast, in the Casamance and Gambia basins, the annual ET0 drops by 65% and 18%, respectively. On an annual scale, temperature and relative humidity show an increasing trend over all basins while wind speed and radiation decrease significantly. This confirms the existence of the "evaporation paradox" in the three basins. This phenomenon is explained by the increase in relative humidity and the decrease in wind speed.

Keywords: Reference evapotranspiration, Penman-Monteith, Mann Kendall test, Senegal, Gambia and Casamance River Basins.

How to cite: Ndiaye, P. M., Bodian, A., Diop, S. B., Diop, L., Dezetter, A., Ogilvie, A., and Djaman, K.: Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-149, https://doi.org/10.5194/iahs2022-149, 2022.