Assess evapotranspiration over Sahelian regions: Review and evaluation of available products and alternative methods. - Archive ouverte HAL
Communication Dans Un Congrès Année : 2022

Assess evapotranspiration over Sahelian regions: Review and evaluation of available products and alternative methods.

Jordi Etchanchu
Hydrosciences Montpellier
Jerome Demarty
  • Fonction : Auteur
Hydrosciences Montpellier
Alain Dezetter
Hydrosciences Montpellier
CV
Albert Olioso
Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes
CV
Aubin Allies
  • Fonction : Auteur
Hydrosciences Montpellier
Felix Marlio
  • Fonction : Auteur
Hydrosciences Montpellier
Ansoumana Bodian
Université Gaston Berger de Saint-Louis Sénégal
Gilles Boulet
Centre d'études spatiales de la biosphère
Lamine Diop
  • Fonction : Auteur
Laboratoire Leidi ( dynamiques des territoires et développement)
Hassane Bil-Assanou Issoufou
  • Fonction : Auteur
Université Dan Dicko Dankoulodo de Maradi
Ibrahim Mainassara
  • Fonction : Auteur
Hydrosciences Montpellier
IRD Représentation du Niger
Andrew Ogilvie
Gestion de l'Eau, Acteurs, Usages
Hélène Barral
  • Fonction : Auteur
Hydrosciences Montpellier
Jean-Philippe Chazarin
  • Fonction : Auteur
Hydrosciences Montpellier
Monique Oï
  • Fonction : Auteur
Hydrosciences Montpellier
Bernard Cappelaere
  • Fonction : Auteur
Hydrosciences Montpellier

Résumé

<p>The estimation of spatialized Evapotranspiration (ET) is of great interest to tackle various scientific issues in hydrology. It is particularly relevant in Sahelian Regions where there is a spatial scarcity of in-situ ET measurements, despite having key issues in water management and food safety. Nowadays, many ET products are available with different temporal and spatial resolutions. These products use a wide range of methods: empirical ET equations, Land Surface Models (LSM), energy balance models, in-situ measurements upscaling, neural networks or data fusion approaches. In this study, a quite exhaustive review of available ET products has been performed over Sahel. We have evaluated the potential of 18 ET products, both at local scale, using eddy-covariance measurements and a LSM calibrated on sahelian ecosystems, and at mesoscale, using the ALMIP2 models ensemble (20 LSM). Results show that only few products succeed at representing realistic temporal and spatial repartition of ET in sahelian context. The wide variety of temporal and spatial resolutions is also limiting the applications of such products, especially in eco-hydrology or agricultural management. Alternative methods are thus proposed to provide more reliable ET estimation over sahelian region by combining multi-sources ET estimations and satellite data. First, derived at kilometer scale using the EVASPA S-SEBI Sahel (E3S) contextual approach and MODIS Thermal Infrared (TIR) data on clear sky days. Then days with clouds have been filled with a data fusion algorithm. This algorithm uses ET estimates from the Amsterdam Methodology (GLEAM); which proved to have one of the best temporal representation of ET in our study area; and/or a simple parametric model (PAMEAS). Annual and seasonal ET estimates have been compared with the existing products on sahelian areas in Niger and Mali, and will be soon in Senegal too in the frame of the EVAP’EAU project (ICIREWARD Unesco Center). The E3S model and temporal interpolation techniques for daily ET estimations are also investigated in the mission group of the TRISHNA satellite mission (CNES-ISRO) which will provide TIR data and products with high spatial (60m) and temporal (3 days) resolution.</p>

Domaines

Milieux et Changements globaux Interfaces continentales, environnement Bioclimatologie

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https://hal.science/hal-04217405

Soumis le : lundi 25 septembre 2023-17:33:09

Dernière modification le : mardi 3 décembre 2024-10:22:03

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hal-04217405 , version 1 (25-09-2023)

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Jordi Etchanchu, Jerome Demarty, Alain Dezetter, Albert Olioso, Aubin Allies, et al.. Assess evapotranspiration over Sahelian regions: Review and evaluation of available products and alternative methods.. XIth Scientific Assembly of the International Association of Hydrological Sciences (IAHS 2022), May 2022, Montpellier, France. ⟨10.5194/iahs2022-121⟩. ⟨hal-04217405⟩

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CIRAD INSU METEO UNIV-AVIGNON BRGM AGROPARISTECH CNRS OMP OMP-CESBIO HSM UNIV-MONTPELLIER G-EAU INSTITUT-AGRO-MONTPELLIER INRAE INRAEOCCITANIEMONTPELLIER EMMAH INRAEOCCITANIETOULOUSE UNIV-UT3 UT3-TOULOUSEINP RESEAU-TELEDETECTION-INRAE RESEAU-EAU INRAEPACA
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