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

<p>Analysis of reference evapotranspiration (ET<span class="inline-formula"><sub>0</sub>)</span> trends is essential for understanding the impacts of climate change on water resources. Thus, despite the continuous rise in temperatures, a decrease in evapotrans...

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Main Authors: P. M. Ndiaye, A. Bodian, S. B. Diop, L. Diop, A. Dezetter, A. Ogilvie, K. Djaman
Format: Article
Language:English
Published: Copernicus Publications 2024-04-01
Series:Proceedings of the International Association of Hydrological Sciences
Online Access:https://piahs.copernicus.org/articles/385/305/2024/piahs-385-305-2024.pdf
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author P. M. Ndiaye
A. Bodian
S. B. Diop
L. Diop
A. Dezetter
A. Ogilvie
K. Djaman
author_facet P. M. Ndiaye
A. Bodian
S. B. Diop
L. Diop
A. Dezetter
A. Ogilvie
K. Djaman
author_sort P. M. Ndiaye
collection DOAJ
description <p>Analysis of reference evapotranspiration (ET<span class="inline-formula"><sub>0</sub>)</span> 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 the annual and seasonal trends of ET<span class="inline-formula"><sub>0</sub></span> and climate variables at the scale of the Senegal, Gambia and Casamance river basins. The reanalyze data of NASA/POWER are used over the period 1984–2019. Mann Kendall's test and Sen slope were used to analyze trends in ET<span class="inline-formula"><sub>0</sub></span> and climate variables. Results show that on annual scale, ET<span class="inline-formula"><sub>0</sub></span> 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 ET<span class="inline-formula"><sub>0</sub></span> 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 and solar radiation.</p>
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spelling doaj.art-f74ec8a1d990432f957ad4a56699b3e52024-04-18T12:57:10ZengCopernicus PublicationsProceedings of the International Association of Hydrological Sciences2199-89812199-899X2024-04-0138530531110.5194/piahs-385-305-2024Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River BasinsP. M. Ndiaye0A. Bodian1S. B. Diop2L. Diop3A. Dezetter4A. Ogilvie5K. Djaman6Laboratoire Leïdi “Dynamique des Territoires et Développement”, Université Gaston Berger (UGB), Saint-Louis BP 234, SenegalLaboratoire Leïdi “Dynamique des Territoires et Développement”, Université Gaston Berger (UGB), Saint-Louis BP 234, SenegalLaboratoire Leïdi “Dynamique des Territoires et Développement”, Université Gaston Berger (UGB), Saint-Louis BP 234, SenegalUFR S2ATA Sciences Agronomiques, de l'Aquaculture et des Technologies Alimentaires, Université Gaston Berger, Saint-Louis BP 234, SenegalHSM, Univ. Montpellier, IRD, CNRS, UFR Pharmacie, Bâtiment HYDROPOLIS, 15 avenue Charles Flahault, 34090 Montpellier, FranceUMR G-EAU, AgroParisTech, Cirad, University of Montpellier, IRD, INRAE, Montpellier SupAgro, 34196 Montpellier, FranceDepartment of Plant and Environmental Sciences, New Mexico State University, Agricultural Science Center at Farmington, P.O. Box 1018, Farmington, NM 87499, USA<p>Analysis of reference evapotranspiration (ET<span class="inline-formula"><sub>0</sub>)</span> 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 the annual and seasonal trends of ET<span class="inline-formula"><sub>0</sub></span> and climate variables at the scale of the Senegal, Gambia and Casamance river basins. The reanalyze data of NASA/POWER are used over the period 1984–2019. Mann Kendall's test and Sen slope were used to analyze trends in ET<span class="inline-formula"><sub>0</sub></span> and climate variables. Results show that on annual scale, ET<span class="inline-formula"><sub>0</sub></span> 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 ET<span class="inline-formula"><sub>0</sub></span> 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 and solar radiation.</p>https://piahs.copernicus.org/articles/385/305/2024/piahs-385-305-2024.pdf
spellingShingle P. M. Ndiaye
A. Bodian
S. B. Diop
L. Diop
A. Dezetter
A. Ogilvie
K. Djaman
Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins
Proceedings of the International Association of Hydrological Sciences
title Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins
title_full Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins
title_fullStr Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins
title_full_unstemmed Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins
title_short Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins
title_sort trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of senegal senegal gambia and casamance river basins
url https://piahs.copernicus.org/articles/385/305/2024/piahs-385-305-2024.pdf
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