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147 results on '"Peugeot, Christophe"'

1. Trop d’eau, pas assez d’eau… se mouiller collectivement pour faire face

Author: Panthou, Geremy, primary, Hector, Basile, additional, and Peugeot, Christophe, additional
Published: 2022
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2. Terrestrial or oceanic forcing? Water level variations in coastal lagoons constrained by river inflow and ocean tides

Author: Morel, Yves, Chaigneau, Alexis, Okpeitcha, Victor Olaègbè, Stieglitz, Thomas, Assogba, Arnaud, Duhaut, Thomas, Rétif, Fabien, Peugeot, Christophe, and Sohou, Zacharie
Published: 2022
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3. Evaluation of Groundwater Simulations in Benin from the ALMIP2 Project

Author: Rashid, Mehnaz, Chien, Rong-You, Ducharne, Agnès, Kim, Hyungjun, Yeh, Pat J.-F., Peugeot, Christophe, Boone, Aaron, He, Xiaogang, Séguis, Luc, Yabu, Yutaro, Boukari, Moussa, and Lo, Min-Hui
Published: 2019

4. Streamflows over a West African Basin from the ALMIP2 Model Ensemble

Author: ALMIP2 Working Group, Getirana, Augusto, Boone, Aaron, and Peugeot, Christophe
Published: 2017

5. Modeling Surface Runoff and Water Fluxes over Contrasted Soils in the Pastoral Sahe : Evaluation of the ALMIP2 Land Surface Models over the Gourma Region in Mali

Author: ALMIP2 WORKING GROUP, Grippa, Manuela, Kergoat, Laurent, Boone, Aaron, Peugeot, Christophe, Demarty, Jérôme, Cappelaere, Bernard, Gal, Laetitia, Hiernaux, Pierre, Mougin, Eric, Ducharne, Agnès, Dutra, Emanuel, Anderson, Martha, and Hain, Christopher
Published: 2017

6. Impact of the COVID19 crisis on changes in business travel and the associated carbon footprint. Case study of a French scientific research institute.

Author: Peugeot, Christophe, primary, Dany, Grolleau, additional, Caroline, Play, additional, Benjamin, Sultan, additional, Valeria, Hernandez, additional, Serge, Janicot, additional, and Yves, Tramblay, additional
Published: 2023
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7. 17O-excess of tropical forest and savanna phytoliths record diurnal atmospheric relative humidity of the growing season: implications for paleoclimate reconstructions and model-data comparisons

Author: Alexandre, Anne, primary, Outrequin, Clément, additional, Peugeot, Christophe, additional, Aleman, Julie, additional, Vallet-Coulomb, Christine, additional, Voigt, Claudia, additional, Au Yang, David, additional, Landais, Amaelle, additional, Mazur, Jean-Charles, additional, Sonzogni, Corinne, additional, Wubda, Maxime, additional, Ouani, Theodore, additional, Afouda, Simon, additional, Grippa, Manuela, additional, Soumaguel, Nogmana, additional, Tagesson, Torbern, additional, Fensholt, Rasmus, additional, Ndiaye, Ousmane, additional, and Mougin, Eric, additional
Published: 2023
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8. Differences in transpiration between a forest and an agroforestry tree species in the Sudanian belt

Author: Awessou, Kohomlan G. Beranger, Peugeot, Christophe, Rocheteau, Alain, Seguis, Luc, Do, Frédéric C., Galle, Sylvie, Bellanger, Marie, Agbossou, Euloge, and Seghieri, Josiane
Published: 2017
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9. Evaluating LSM-Based Water Budgets over a West African Basin Assisted with a River Routing Scheme

Author: Getirana, Augusto C. V., Boone, Aaron, and Peugeot, Christophe
Published: 2014

10. Tipping points in hydrology: observed regional regime shift and System Dynamics modeling

Author: Wendling, Valentin, Peugeot, Christophe, Grippa, Manuela, Kergoat, Laurent, Mougin, Eric, Hiernaux, Pierre, Rouché, Nathalie, Panthou, Geremy, Rajot, Jean-Louis, Pierre, Caroline, Mora, Olivier, Garcia-Mayor, Angeles, Ba, Abdramane, Lawin, Emmanuel, Bouzou-Moussa, Ibrahim, Demarty, Jerôme, Etchanchu, Jordi, Hector, Basile, Galle, Sylvie, Lebel, Thierry, Project, Tiphyc, Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Délégation à l'Expertise scientifique collective, à la Prospective et aux Etudes (UAR), Institut National de la Recherche Agronomique (INRA), Utrecht University [Utrecht], Institut National de L’Eau, Cotonou, Université Abdou Moumouni [Niamey], Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), ANR : Exploring tipping points in the West African hydrological cycle – TipHyc, and ANR-20-CE01-0014,TipHyc,Exploration des points de bascule dans le cycle hydrologique ouest-africain(2020)
Subjects: [SDE.MCG]Environmental Sciences/Global Changes, [NLIN]Nonlinear Sciences [physics], [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract: River runoff and climate data existing from 1950 to present time in West Africa are analyzed over a climatic gradient from the Sahel (semi-arid) to the Gulf of Guinea (humid). The region experienced a severe drought in the 70s-90s, with strong impact on the vegetation, soils and populations. We show that the hydrological regime in the Sahel has shifted: the runoff increased significantly between pre- and post-drought periods and is still increasing. In the Guinean region, instead, no shift is observed. This suggests that a tipping point could have been passed, triggered by climate and/or land use change. In order to explore this hypothesis, we developed a System Dynamics model representing feedbacks between soil, vegetation and flow connectivity of hillslopes, channels and aquifers. Model runs were initialized in 1950 with maps of land use/land cover, and fed with observed rainfall (climate external forcing). The modeling results accurately represent the observed evolution of the hydrological regime on the watersheds monitored since the 50s (ranging from 1 to 50000 km²). The model revealed that alternative stable states can exist for the climatic conditions of the study period. From the model runs, we showed that the drought triggered the crossing of a tipping point (rainfall threshold), which explains the regime shift. We identified domains within the watersheds where tipping occurred at small scale, leading to larger scale shifts. This result supports that tipping points exist in semi-arid systems where ecohydrology plays a major role. This approach seems well suited to identify areas of high risk of irreversible hydrological regime shifts under different climate and land-use scenarios.
Published: 2022

11. From seasonal flood pulse to seiche: Multi-frequency water-level fluctuations in a large shallow tropical lagoon (Nokoué Lagoon, Benin)

Author: Chaigneau, Alexis, primary, Okpeitcha, Olaègbè Victor, additional, Morel, Yves, additional, Stieglitz, Thomas, additional, Assogba, Arnaud, additional, Benoist, Morgane, additional, Allamel, Pierre, additional, Honfo, Jules, additional, Awoulmbang Sakpak, Thierry Derol, additional, Rétif, Fabien, additional, Duhaut, Thomas, additional, Peugeot, Christophe, additional, and Sohou, Zacharie, additional
Published: 2022
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12. The AMMA-CATCH observatory : a platform to address scientific and societal issues in West-Africa

Author: Cohard, Jean-Martial, primary, Grippa, Manuela, additional, Lawin, Emmanuel, additional, Peugeot, Christophe, additional, Assanou, Bil, additional, Boucher, Marie, additional, Chaffard, Véronique, additional, Diawara, Mamadou, additional, Etchanchu, Jordi, additional, Faye, Gayane, additional, Galle, Sylvie, additional, Mainassara, Ibrahim, additional, Malam-Abdou, Moussa, additional, Mamadou, Ossenatou, additional, Mariscal, Armand, additional, Mougin, Eric, additional, Moumouni, Soumaïla, additional, Panthou, Geremy, additional, and Lebel, Thierry, additional
Published: 2022
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13. A parametric sensitivity analysis for prioritizing regolith knowledge needs for modeling water transfers in the West African critical zone

Author: Herzog, Amelie, Hector, Basile, Cohard, Jean Martial, Vouillamoz, Jean Michel, Lawson, Fabrice Messan Amene, Peugeot, Christophe, and de Graaf, Inge
Subjects: Environmental sciences, QE1-996.5, Life Science, Water Systems and Global Change, GE1-350, Geology
Abstract: Hard rock aquifers (HRAs) in West Africa (WA) are located within a thick regolith layer. The representation of thick tropical regolith in integrated hydrological models lacks consensus on aquifer geometries and parameter ranges. Our main objective was to determine the knowledge requirements on saturated hydraulic conductivity (Ks) to model the critical zone (CZ) of HRAs in WA. A parametric sensitivity analysis with a focus on the representation of the Ks heterogeneity of the regolith was conducted with a critical zone model (Parflow‐CLM [Community Land Model]) of the Upper Ouémé catchment in Benin (14,000 km2) at a 1‐ × 1‐km2 resolution. The impact of parameter changes in the near subsurface (0.3‐to‐5‐m depth) and in the deeper regolith aquifer (24‐ and 48‐m maximum depth) was assessed in five modeling experiments. Streamflow was largely dependent on Ks and on clay distribution in the near subsurface and less on the properties of the deeper subsurface. Groundwater table depths and amplitudes were controlled by vegetation and topography as observed on instrumented hillslopes and for Ks within the literature range. Experiments with higher Ks suggested a Ks threshold where dynamics become less determined by one‐dimensional vertical and more determined by lateral processes. Such heterogeneity impacts from smaller scales need to be accounted for when hydrological models are upscaled to larger domains (1‐ × 1‐km2 resolution or coarser). Our findings highlight the need for a new conceptual approach to represent clay distribution in order to develop catchment‐scale CZ models of HRAs in WA that capture the observed processes.
Published: 2021

14. From seasonal flood pulse to seiche: Multi-frequency waterlevel fluctuations in a large shallow tropical lagoon (Nokoué Lagoon, Benin)

Author: Chaigneau, Alexis, Okpeitcha, Victor, Morel, Yves, Stieglitz, Thomas, Assogba, Arnaud, Benoist, Morgane, Allamel, Pierre, Honfo, Jules, Derol, Thierry, Sakpak, Awoulmbang, Rétif, Fabien, Duhaut, Thomas, Peugeot, Christophe, Sohou, Zacharie, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Seiches, Wavelet analysis, Tides, Nokoué, Water-levels, Lagoons
Abstract: This study investigated the main water-level (WL) variability modes of Nokoué Lagoon in Benin (West-Africa). The average WL ranges between 1.3 and 2.3 m between the low-and high-water seasons. Seasonal as well as weak interannual variations between 2018 and 2019 are driven by rainfall regime over the catchment and associated river inflow. At sub-monthly scales, the lagoon is tidally choked: ocean tides can reach 90 cm, whereas in the lagoon semi-diurnal and diurnal tides hardly reach few centimeters. Choking conditions vary with river inflow and ocean tide amplitude, correctly represented by a simple tidal choking model. Diurnal modulation and asymmetry of the tide are stronger (weaker) during high (low) water period. We also observed WL variations of ±5-10 cm at a fortnightly frequency, stronger during wet (high-water) season. Superimposed on the seasonal, fortnightly and tidal WL variations, we further observed short-term high-frequency seiche events. Mostly observed during dry (low-water) conditions, they are characterized by typical standing-wave oscillations of 5-10 cm amplitudes and 3 h periods. They are forced by the passage of fast-moving squall-lines that induce strong wind variations, heavy rainfalls and rapid drop-off of the air temperature. Results obtained in this study provide useful metrics for the validation of flood forecasting models to be implemented in Benin, and elsewhere on the West African coastline.
Published: 2021

15. The triple oxygen isotope composition of phytoliths, a proxy of relative humidity: impact of the triple oxygen isotope composition of soil water and vegetation type

Author: Vallet-Coulomb, Christine, Alexandre, A., Outrequin, Clément, Peugeot, Christophe, Couapel, Martine, Landais, Amaelle, Mazur, Jean-Charles, Sonzogni, Corinne, Wubda, Maxime, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), and Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: [SDE]Environmental Sciences
Abstract: International audience; Continental atmospheric humidity is a key climate parameter poorly captured by global climate models. Model-data comparison approaches applicable beyond the instrumental period are essential to progress on this issue but face a lack of relative humidity records. This study is part of the HUMI-17 project that assesses the robustness of the 17O-excess of phytoliths as a proxy of past changes in atmospheric relative humidity. Here, the impact of the triple oxygen isotope composition of soil water and vegetation type on the triple oxygen isotope composition of phytoliths is examined. We additionally assess which relative humidity (annual or seasonal? averaged over the plant growing period or over the growing period and the beginning of senescence?) is registered by the 17O-excess of phytoliths. At last, we examine how tree phytoliths contribute to the relative humidity proxy. For that purpose, rainwater, soil cores, grasses and trees were sampled at the AMMA-CATCH natural observatory in Benin (West Africa) where dry forest and savannas develop under a tropical humid climate. The site is equipped with a meteorological station. The triple oxygen isotope compositions of rainwater, soil water and plant water were analyzed by isotope ratio mass spectrometry (IRMS) and cavity ring-down spectrometry. Phytoliths were analyzed by laser-fluorination-IRMS. For robust comparisons between triple oxygen isotope compositions acquired by different analytical techniques, on different phases, inter-laboratory comparisons have been carried out. Overall, the results bring us closer to an accurate proxy of changes in relative humidity.
Published: 2021

16. The triple oxygen isotope composition of phytoliths, a new proxy of atmospheric relative humidity: controls of soil water isotope composition, temperature, CO<sub>2</sub> concentration and relative humidity

Author: Outrequin, Clément, primary, Alexandre, Anne, additional, Vallet-Coulomb, Christine, additional, Piel, Clément, additional, Devidal, Sébastien, additional, Landais, Amaelle, additional, Couapel, Martine, additional, Mazur, Jean-Charles, additional, Peugeot, Christophe, additional, Pierre, Monique, additional, Prié, Frédéric, additional, Roy, Jacques, additional, Sonzogni, Corinne, additional, and Voigt, Claudia, additional
Published: 2021
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17. AMMA-CATCH studies in the Sahelian region of West-Africa: An overview

Author: Lebel, Thierry, Cappelaere, Bernard, Galle, Sylvie, Hanan, Niall, Kergoat, Laurent, Levis, Samuel, Vieux, Baxter, Descroix, Luc, Gosset, Marielle, Mougin, Eric, Peugeot, Christophe, and Seguis, Luc
Published: 2009
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18. Relationships between climate, soil moisture and phenology of the woody cover in two sites located along the West African latitudinal gradient

Author: Seghieri, Josiane, Vescovo, Aude, Padel, Karine, Soubie, Remy, Arjounin, Marc, Boulain, Nicolas, de Rosnay, Patricia, Galle, Sylvie, Gosset, Marielle, Mouctar, Abakar H., Peugeot, Christophe, and Timouk, Franck
Published: 2009
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19. The ADHI dataset: African Database of Hydrometric Indices: new perspectives for African hydrology studies

Author: Rouché, Nathalie, Tramblay, Yves, Paturel, J.-E., Mahe, Gil, Boyer, Jean-François, Amoussou, Ernest, Bodian, Ansoumana, Dacosta, Honoré, Dakhlaoui, Hamouda, Dezetter, A., Hughes, Denis, Hanich, Lahoucine, Peugeot, Christophe, Tshimanga, Raphael, Lachassagne, Patrick, Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Parakou (UP), Université Gaston Berger de Saint-Louis Sénégal (UGB), Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD), University of Tunis El Manar, Université de Carthage - University of Carthage, Rhodes University, Grahamstown, Université Cadi Ayyad [Marrakech] (UCA), Université Mohammed VI Polytechnique [Ben Guerir] (UM6P), University of Kinshasa (UNIKIN), and European Geosciences Union
Subjects: [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology
Abstract: Poster réalisé par l'Institut de recherche pour le développement et le laboratoire Hydrosciences Montpellier; International audience; At the African scale, there is a lack of coordination for hydrological data collection and dissemination : hydrological data is often scattered, heterogeneous or incomplete Numerous public, semi-public and private organizations produce and manage data, but often they do not have the resources to exchange, standardize, summarize and apitalize on the data they generate There is not enough partnership between the national hydrological services, in many countries licensing issues prevent the distribution of the data collected. There is also a more general problem of a widespread reluctance to share information There is need to develop links between data producers and users to reinforce capacities for accessing, processing and take benefit from existing data.As a consequence, the African continent is largely under-represented in global scale studies.
Published: 2021

20. Supplementary material to "The triple oxygen isotope composition of phytoliths, a new proxy of atmospheric relative humidity: controls of soil water isotope composition, temperature, CO2 concentration and relative humidity"

Author: Outrequin, Clément, primary, Alexandre, Anne, additional, Vallet-Coulomb, Christine, additional, Piel, Clément, additional, Devidal, Sébastien, additional, Landais, Amaelle, additional, Couapel, Martine, additional, Mazur, Jean-Charles, additional, Peugeot, Christophe, additional, Pierre, Monique, additional, Prié, Frédéric, additional, Roy, Jacques, additional, Sonzogni, Corinne, additional, and Voigt, Claudia, additional
Published: 2021
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21. ADHI: the African Database of Hydrometric Indices (1950–2018)

Author: Tramblay, Yves, primary, Rouché, Nathalie, additional, Paturel, Jean-Emmanuel, additional, Mahé, Gil, additional, Boyer, Jean-François, additional, Amoussou, Ernest, additional, Bodian, Ansoumana, additional, Dacosta, Honoré, additional, Dakhlaoui, Hamouda, additional, Dezetter, Alain, additional, Hughes, Denis, additional, Hanich, Lahoucine, additional, Peugeot, Christophe, additional, Tshimanga, Raphael, additional, and Lachassagne, Patrick, additional
Published: 2021
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22. ADHI: The African Database of Hydrometric Indices (1950-2018)

Author: Rouché, Nathalie, primary, Tramblay, Yves, additional, Paturel, Jean-Emmanuel, additional, Mahé, Gil, additional, Boyer, Jean-François, additional, Amoussou, Ernest, additional, Bodian, Ansoumana, additional, Dacosta, Honoré, additional, Dakhlaoui, Hamouda, additional, Dezetter, Alain, additional, Hughes, Denis, additional, Hanich, Lahoucine, additional, Peugeot, Christophe, additional, Tshimanga, Raphael, additional, and Lachassagne, Patrick, additional
Published: 2021
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23. Impact du changement global sur les systèmes lagunaires en Afrique de l'Ouest : le cas du lac Nokoué au Bénin

Author: Chaigneau, Alexis, Stieglitz, Thomas Christian, Okpeitcha, V., Assogba, A., Sohou, Z., Peugeot, Christophe, Morel, Y., Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Hydrosciences Montpellier (HSM), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)
Subjects: [SDV.EE]Life Sciences [q-bio]/Ecology, environment, AFRIQUE DE L'OUEST, [SDV.SA.STP]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of fishery, BENIN, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology
Published: 2020

24. Influence of observed and RCM-simulated precipitation on the water discharge over the Sirba basin, Burkina Faso/Niger

Author: Messager, Christophe, Gallée, Hubert, Brasseur, Olivier, Cappelaere, Bernard, Peugeot, Christophe, Séguis, Luc, Vauclin, Michel, Ramel, Romain, Grasseau, Gilles, Léger, Laurent, and Girou, Denis
Published: 2006
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25. The triple oxygen isotope composition of phytoliths, a proxy of relative humidity: impact of the triple oxygen isotope composition of soil water and vegetation type

Author: Alexandre, Anne, primary, Sonzogni, Corinne, additional, Outrequin, Clément, additional, Vallet-Coulomb, Christine, additional, Peugeot, Christophe, additional, Afouda, Simon, additional, Couapel, Martine, additional, Landais, Amaelle, additional, Mazur, Jean-Charles, additional, Ouani, Theodore, additional, and Wubda, Maxime, additional
Published: 2021
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26. The African Database of Hydrometric Indices (ADHI)

Author: Tramblay, Yves, primary, Rouché, Nathalie, additional, Paturel, Jean-Emmanuel, additional, Mahé, Gil, additional, Boyer, Jean-François, additional, Amoussou, Ernest, additional, Bodian, Ansoumana, additional, Dacosta, Honoré, additional, Dakhlaoui, Hamouda, additional, Dezetter, Alain, additional, Hughes, Denis, additional, Hanich, Lahoucine, additional, Peugeot, Christophe, additional, Tshimanga, Raphael, additional, and Lachassagne, Patrick, additional
Published: 2020
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27. Factors controlling the triple oxygen isotope composition of grass leaf water and phytoliths: insights for paleo-environmental reconstructions

Author: Alexandre, Anne, primary, Outrequin, Clément, additional, Vallet-Coulomb, Christine, additional, Landais, Amaelle, additional, Piel, Clément, additional, Devidal, Sébastien, additional, Peugeot, Christophe, additional, Ouani, Théodor, additional, Afouda, Simon, additional, Couapel, Martine, additional, Sonzogni, Corinne, additional, Mazur, Jean-Charles, additional, Prié, Frédéric, additional, and Webb, Elizabeth, additional
Published: 2020
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28. Contribution of the triple oxygen isotope composition of precipitation to the identification of surface-atmosphere interactions in the sub-humid part of West Africa

Author: Vallet-Coulomb, Christine, primary, Alexandre, Anne, additional, Peugeot, Christophe, additional, Alassane, Abdoukarim, additional, Gbewezoun, Vinel, additional, Couapel, Martine, additional, Outrequin, Clément, additional, Ouani, Théodore, additional, and Afouda, Simon, additional
Published: 2020
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29. Drought-induced regime shift and resilience of a Sahelian ecohydrosystem

Author: Wendling, Valentin, Peugeot, Christophe, Mayor, Ángeles Garcia, Hiernaux, Pierre, Mougin, Eric, Grippa, Manuela, Kergoat, Laurent, Walcker, Romain, Galle, Sylvie, Lebel, Thierry, Spatial Ecology and Global Change, Environmental Sciences, Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Copernicus Institute for Sustainable Development, Utrecht University [Utrecht], Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d'étude des transferts en hydrologie et environnement (LTHE), Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Spatial Ecology and Global Change, and Environmental Sciences
Subjects: 010504 meteorology & atmospheric sciences, rainfall, Climate change, alternative stable states, 010501 environmental sciences, 01 natural sciences, Alternative stable state, Soil retrogression and degradation, Sahel, Clearing, Ecosystem, Regime shift, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, 2. Zero hunger, regime shifts, rainfall variability, Renewable Energy, Sustainability and the Environment, variability, Public Health, Environmental and Occupational Health, Vegetation, 15. Life on land, 13. Climate action, Climatology, [SDE]Environmental Sciences, eco-hydrology, Environmental science, Surface runoff
Abstract: International audience; The Sahel (a semi-arid fringe south of the Sahara) experienced a long and prolonged drought from the1970s to the mid-1990s, with a few extremely severe episodes that strongly affected ecosystems andsocieties. Long-term observations showed that surface runoff increased during this period, despite therainfall deficit. This paradox stems from the soil degradation that was induced by various factors,either directly linked to the drought (impact on vegetation cover), or, in places, to human practices (land clearing and cropping). Surface runoff is still increasing throughout the region, suggesting that Sahelian ecohydrosystems may have shifted to a new hydrological regime. In order to explore this issue, we have developed a simple system dynamics model incorporating vegetation–hydrology interactions and representing in a lumped way the first order processes occurring at the hillslope scale and the annual timestep. Long term observations on a pilot site in northern Mali were used to constrain the model and define an ensemble of plausible simulations. The model successfully reproduced the vegetation collapse and the runoff increase observed over the last 60 years. Our results confirmed that the system presents two alternative states and that during the drought it shifted from a high-vegetation/low-runoff regime to the alternative low-vegetation/high-runoff one, where it has remained trapped until now. We showed that the mean annual rainfall deficit was sufficient to explain the shift. According to the model, vegetation recovery and runoff reduction are possible in this system, but the conditions in which they could occur remain uncertain as the model was only constrained by observations over the collapse trajectory. The study shows that the system is also sensitive to the interannual and decadal variability of rainfall, and that larger variability leads to higher runoff. Both mean rainfall and rainfall variability may increase in central Sahel under climate change, leading to antagonist effects on the system, which makes its resilience uncertain.
Published: 2019

30. Changement climatique, croissance démographique, crises alimentaires et sécuritaires en Afrique sub-saharienne : le lien est-il vraiment établi ?

Author: Golaz, Valérie, Peugeot, Christophe, Institut national d'études démographiques (INED), and Sohler, Karin
Subjects: [SHS] Humanities and Social Sciences, [SHS]Humanities and Social Sciences
Abstract: Changement climatique et croissance démographique sont souvent associés au risque alimentaire et sécuritaire dans la presse* et les études qui circulent au sujet de l'Afrique sub-saharienne. Mais qu'en est-il vraiment? Comment sont estimés ces deux phénomènes? A quelles conséquences portent-ils? Comment sont ils liés?
Published: 2019

31. Agroforesterie et services écosystémiques en zone tropicale

Author: Awessou Kohomlan, G.B., Peugeot, Christophe, Agbossou, E., Seghieri, Josiane, Seghieri, Josiane (coord.), and Harmand, J.M. (coord.)
Abstract: En zone soudanienne, les cultures sont pratiquées depuis des siècles par les populations rurales sous forme d'agroforesterie. Cette pratique est dominée par les parcs à karités (Vitellaria paradoxa), en alternance avec les jachères dans lesquelles les arbres se régénèrent. Pour évaluer les possibilités de densification en karité de ces parcs, nous avons quantifié la transpiration à l'échelle de l'arbre et à celle de la population de karité au sein d'une jachère de dix ans située au nord du Bénin. La densité de flux de sève a été mesurée par la méthode de dissipation thermique transitoire. La transpiration à l'échelle de l'arbre a été déduite de la densité de flux de sève puis extrapolée à celle de la population. Les résultats des trois années d'étude (2011-2013) montrent que la transpiration d'un arbre augmente de 4 à 27 l/jour en fonction de son diamètre (8 à 38 cm). La transpiration varie peu entre la saison des pluies et la saison sèche, suggérant que l'eau n'est pas le facteur limitant. Mais elle diminue brutalement au moment du renouvellement des feuilles (février-mars). À l'échelle de la population de karités, la transpiration reste très faible (0,03 mm/jour) et représente 0,42 % à 1,32 % de la demande atmosphérique estimée par l'évapotranspiration de référence, et 1,15 % de la pluie annuelle. Ces résultats indiquent qu'une augmentation importante de la densité des arbres est possible. Cependant, la seule estimation des besoins en eau des karités reste insuffisante pour améliorer la gestion des parcs agroforestiers et intensifier leur production. Il faudra en effet faire des compromis entre la densification des arbres et l'impact de la lumière incidente filtrée par leur canopée sur la limitation de la production de la culture associée.
Published: 2019

32. Drought-induced regime shift and resilience of a Sahelian ecohydrosystem

Author: Spatial Ecology and Global Change, Environmental Sciences, Wendling, Valentin, Peugeot, Christophe, Mayor, Ángeles Garcia, Hiernaux, Pierre, Mougin, Eric, Grippa, Manuela, Kergoat, Laurent, Walcker, Romain, Galle, Sylvie, Lebel, Thierry, Spatial Ecology and Global Change, Environmental Sciences, Wendling, Valentin, Peugeot, Christophe, Mayor, Ángeles Garcia, Hiernaux, Pierre, Mougin, Eric, Grippa, Manuela, Kergoat, Laurent, Walcker, Romain, Galle, Sylvie, and Lebel, Thierry
Published: 2019

33. Hydrologic process simulation of a semiarid, endoreic catchment in Sahelian West Niger. 1. Model-aided data analysis and screening

Author: Peugeot, Christophe, Cappelaere, Bernard, Vieux, Baxter E., Séguis, Luc, and Maia, Ana
Published: 2003
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34. Hydrologic process simulation of a semiarid, endoreic catchment in Sahelian West Niger. 2. Model calibration and uncertainty characterization

Author: Cappelaere, Bernard, Vieux, Baxter E., Peugeot, Christophe, Maia, Ana, and Séguis, Luc
Published: 2003
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35. OZCAR: The French Network of Critical Zone Observatories

Author: Gaillardet, J., Braud, I., Hankard, F., Anquetin, S., Bour, O., Dorfliger, N., de Dreuzy, J. R., Galle, Sylvie, Galy, C., Gogo, S., Gourcy, L., Habets, F., Laggoun, F., Longuevergne, L., Le Borgne, T., Naaim-Bouvet, F., Nord, G., Simonneaux, Vincent, Six, D., Tallec, T., Valentin, Christian, Abril, G., Allemand, P., Arenes, A., Arfib, B., Arnaud, L., Arnaud, N., Arnaud, P., Audry, S., Comte, V. B., Batiot, C., Battais, A., Bellot, H., Bernard, E., Bertrand, C., Bessiere, H., Binet, S., Bodin, J., Bodin, X., Boithias, Laurie, Bouchez, J., Boudevillain, B., Moussa, I. B., Branger, F., Braun, Jean-Jacques, Brunet, P., Caceres, B., Calmels, D., Cappelaere, Bernard, Celle-Jeanton, H., Chabaux, F., Chalikakis, K., Champollion, C., Copard, Y., Cotel, C., Davy, P., Deline, P., Delrieu, G., Demarty, Jérome, Dessert, C., Dumont, M., Emblanch, C., Ezzahar, J., Esteves, Michel, Favier, V., Faucheux, M., Filizola, N., Flammarion, P., Floury, P., Fovet, O., Fournier, M., Francez, A. J., Gandois, L., Gascuel, C., Gayer, E., Genthon, C., Gerard, M. F., David, Gilbert, Gouttevin, I., Grippa, M., Gruau, G., Jardani, A., Jeanneau, L., Join, J. L., Jourde, H., Karbou, F., Labat, D., Lagadeuc, Y., Lajeunesse, E., Lastennet, R., Lavado, W., Lawin, E., Lebel, Thierry, Le Bouteiller, C., Legout, C., Lejeune, Y., Le Meur, E., Le Moigne, N., Lions, J., Lucas, A., Malet, J. P., Marais-Sicre, C., Marechal, J. C., Marlin, C., Martin, P., Martins, J., Martinez, Jean-Michel, Massei, N., Mauclerc, A., Mazzilli, N., Molenat, J., Moreira Turcq, Patricia, Mougin, E., Morin, S., Ngoupayou, J. N., Panthou, G., Peugeot, Christophe, Picard, G., Pierret, M. C., Porel, G., Probst, A., Probst, J. L., Rabatel, A., Raclot, Damien, Ravanel, L., Rejiba, F., Rene, P., Ribolzi, Olivier, Riotte, Jean, Riviere, A., Robain, Henri, Ruiz, Laurent, Sanchez-Perez, J. M., Santini, William, Sauvage, S., Schoeneich, P., Seidel, J. L., Sekhar, M., Sengtaheuanghoung, O., Silvera, Norbert, Steinmann, M., Soruco, A., Tallec, G., Thibert, E., Lao, D. V., Vincent, Christine, Viville, D., Wagnon, Patrick, and Zitouna, R.
Subjects: lcsh:GE1-350, lcsh:Geology, lcsh:QE1-996.5, lcsh:Environmental sciences
Abstract: The French critical zone initiative, called OZCAR (Observatoires de la Zone Critique–Application et Recherche or Critical Zone Observatories–Application and Research) is a National Research Infrastructure (RI). OZCAR-RI is a network of instrumented sites, bringing together 21 pre-existing research observatories monitoring different compartments of the zone situated between “the rock and the sky,” the Earth’s skin or critical zone (CZ), over the long term. These observatories are regionally based and have specific initial scientific questions, monitoring strategies, databases, and modeling activities. The diversity of OZCAR-RI observatories and sites is well representative of the heterogeneity of the CZ and of the scientific communities studying it. Despite this diversity, all OZCAR-RI sites share a main overarching mandate, which is to monitor, understand, and predict (“earthcast”) the fluxes of water and matter of the Earth’s near surface and how they will change in response to the “new climatic regime.” The vision for OZCAR strategic development aims at designing an open infrastructure, building a national CZ community able to share a systemic representation of the CZ , and educating a new generation of scientists more apt to tackle the wicked problem of the Anthropocene. OZCAR articulates around: (i) a set of common scientific questions and cross-cutting scientific activities using the wealth of OZCAR-RI observatories, (ii) an ambitious instrumental development program, and (iii) a better interaction between data and models to integrate the different time and spatial scales. Internationally, OZCAR-RI aims at strengthening the CZ community by providing a model of organization for pre-existing observatories and by offering CZ instrumented sites. OZCAR is one of two French mirrors of the European Strategy Forum on Research Infrastructure (eLTER-ESFRI) project.
Published: 2018

36. Modélisation des cycles couplés de l'eau, de l'énergie et de la végétation sur les surfaces continentales

Author: Demarty, Jérôme, Cappelaere, Bernard, Peugeot, Christophe, Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Arnaud, N. (ed.), Jouve, B. (ed.), and Müller, J.P. (ed.)
Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2018

37. Hydrological functioning of western African inland valleys explored with a critical zone model

Author: Hector, Basile, Cohard, Jean-Martial, Séguis, Luc, Galle, Sylvie, and Peugeot, Christophe
Subjects: lcsh:GE1-350, lcsh:G, lcsh:T, lcsh:Geography. Anthropology. Recreation, lcsh:Environmental technology. Sanitary engineering, lcsh:Technology, lcsh:TD1-1066, lcsh:Environmental sciences
Abstract: Inland valleys are seasonally waterlogged headwater wetlands, widespread across western Africa. Their role in the hydrological cycle in the humid, hard-rock-dominated Sudanian savanna is not yet well understood. Thus, while in the region recurrent floods are a major issue, and hydropower has been recognized as an important development pathway, the scientific community lacks precise knowledge of streamflow (Q) generation processes and how they could be affected by the presence of inland valleys. Furthermore, inland valleys carry an important agronomic potential, and with the strong demographic rates of the region, they are highly subject to undergoing land cover changes. We address both the questions of the hydrological functioning of inland valleys in the Sudanian savanna of western Africa and the impact of land cover changes on these systems through deterministic sensitivity experiments using a physically based critical zone model (ParFlow-CLM) applied to a virtual generic catchment which comprises an inland valley. Model forcings are based on 20 years of data from the AMMA-CATCH observation service and parameters are evaluated against multiple field data (Q, evapotranspiration – ET –, soil moisture, water table levels, and water storage) acquired on a pilot elementary catchment. The hydrological model applied to the conceptual lithological/pedological model proposed in this study reproduces the main behaviours observed, which allowed those virtual experiments to be conducted. We found that yearly water budgets were highly sensitive to the vegetation distribution: average yearly ET for a tree-covered catchment (944 mm) exceeds that of herbaceous cover (791 mm). ET differences between the two covers vary between 12 % and 24 % of the precipitation of the year for the wettest and driest years, respectively. Consequently, the tree-covered catchment produces a yearly Q amount of 28 % lower on average as compared to a herbaceous-covered catchment, ranging from 20 % for the wettest year to 47 % for a dry year. Trees also buffer interannual variability in ET by 26 % (with respect to herbaceous). On the other hand, pedological features (presence – or absence – of the low-permeability layer commonly found below inland valleys, upstream and lateral contributive areas) had limited impact on yearly water budgets but marked consequences for intraseasonal hydrological processes (sustained/non-sustained baseflow in the dry season, catchment water storage redistribution). Therefore, subsurface features and vegetation cover of inland valleys have potentially significant impacts on downstream water-dependent ecosystems and water uses as hydropower generation, and should focus our attention.
Published: 2018

38. Consommation en eau d’une espèce agroforestière en zone soudanienne

Author: Awessou, B. Kohomlan, Peugeot, Christophe, Agbossou, Euloge K, Seghieri, Josiane, LHME/FSA, Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Faculté des Sciences Agronomiques (FSA), University of Abomey Calavi (UAC), and Seghieri J. & Harmand J-M.
Subjects: [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2018

39. The triple oxygen isotope composition of phytoliths, a new proxy of atmospheric relative humidity: controls of soil water isotope composition, temperature, CO2 concentration and relative humidity.

Author: Outrequin, Clément, Alexandre, Anne, Vallet-Coulomb, Christine, Piel, Clément, Devidal, Sébastien, Landais, Amaelle, Couapel, Martine, Mazur, Jean-Charles, Peugeot, Christophe, Pierre, Monique, Prié, Frédéric, Roy, Jacques, Sonzogni, Corinne, and Voigt, Claudia
Abstract: Continental atmospheric relative humidity is a major climate parameter whose variability is poorly understood by global climate models. Models' improvement relies on model-data comparisons for past periods. However, there are no truly quantitative indicators of relative humidity for the pre-instrumental period. Previous studies highlighted a quantitative relationship between the triple oxygen isotope composition of phytoliths, and particularly the 17O-excess of phytoliths, and atmospheric relative humidity. Here, as part of a series of calibrations, we examine the respective controls of soil water isotope composition, temperature, CO2 concentration and relative humidity on phytolith 17O-excess. For that purpose, the grass species Festuca arundinacea was grown in growth chambers where these parameters were varying. The setup was designed to control the evolution of the triple oxygen isotope composition of phytoliths and all the water compartments of the soil-plant-atmosphere continuum. Different analytical techniques (cavity ring-down spectroscopy and isotope ratio mass spectrometry) were used to analyse water and silica. An inter-laboratory comparison allowed to strengthen the isotope data matching. Water and phytolith isotope compositions were compared to previous datasets obtained from growth chamber and natural tropical sites. The results show that the d'18O value of the source water governs the starting point from which the triple oxygen isotope composition of leaf water, phytolith-forming water and phytoliths evolve. However, since the 17O-excess varies little in the growth chamber and natural source waters, this has no impact on the strong relative humidity-dependency of the 17O-excess of phytoliths, demonstrated for the 40-80% relative humidity range. This relative humidity-dependency is not impacted by changes in air temperature or CO2 concentration either. A relative humidity proxy equation is proposed. Each per meg of change in phytolith 17O-excess reflects a change in atmospheric relative humidity of ca. 0.2 %. The Â± 15 per meg reproducibility on the measurement of phytolith 17O-excess corresponds to a Â± 3.6 % precision on the reconstructed relative humidity. The low sensitivity of phytolith 17O-excess to climate parameters other than relative humidity makes it particularly suitable for quantitative reconstructions of continental relative humidity changes in the past. [ABSTRACT FROM AUTHOR]
Published: 2021
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40. Streamflows over a West African Basin from the ALMIP2 Model Ensemble

Author: Getirana, Augusto, Boone, Aaron, Peugeot, Christophe, Ait-Mesbah, S., Polcher, J., Anderson, M., Balsamo, G., Boussetta, S., Dutra, E., Pappenberger, F., Hain, C., Favot, F., Guichard, F., Kaptue, A., Cappelaere, B., Demarty, Jérôme, Seguis, L., Chaffard, V., Cohard, J. M., Gascon, T., Galle, S., Hector, B., Lebel, T., Pellarin, T., Richard, A., Quantin, G., Vischel, T., Chan, E., Verseghy, D., Ducharne, Agnès, Magand, C., Grippa, Manuela, Hiernaux, Pierre, Kergoat, Laurent, Pierre, C., Nasonova, Y. Gusev O., Harris, P., He, X., Yorozu, K., Kotsuki, S., Tanaka, K., Kim, H., Oki, T., Kumar, S., Lo, M.-H., Mahanama, S., Maignan, F., Ottlé, C., Mamadou, O., Shmakin, A., Sokratov, V., Turkov, D., Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de Recherche pour le Développement (IRD), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Hydrology, Atmospheric Science, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Hydrological modelling, 0208 environmental biotechnology, Mesoscale meteorology, Drainage basin, 02 engineering and technology, Groundwater recharge, Infiltration (HVAC), Monsoon, 01 natural sciences, 6. Clean water, 020801 environmental engineering, Climatology, Streamflow, Environmental science, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, Surface runoff, 0105 earth and related environmental sciences
Abstract: Comparing streamflow simulations against observations has become a straightforward way to evaluate a land surface model’s (LSM) ability in simulating water budget within a catchment. Using a mesoscale river routing scheme (RRS), this study evaluates simulated streamflows over the upper Ouémé River basin resulting from 14 LSMs within the framework of phase 2 of the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Model Intercomparison Project (ALMIP2). The ALMIP2 RRS (ARTS) has been used to route LSM outputs. ARTS is based on the nonlinear Muskingum–Cunge method and a simple deep water infiltration formulation representing water-table recharge as previously observed in that region. Simulations are performed for the 2005–08 period during which ground observations are largely available. Experiments are designed using different ground-based rainfall datasets derived from two interpolation methods: the Thiessen technique and a combined kriging–Lagrangian methodology. LSM-based total runoff (TR) averages vary from 0.07 to 1.97 mm day−1, while optimal TR was estimated as ~0.65 mm day−1. This highly affected the RRS parameterization and streamflow simulations. Optimal Nash–Sutcliffe coefficients for LSM-averaged streamflows varied from 0.66 to 0.92, depending on the gauge station. However, individual LSM performances show a wider range. A more detailed rainfall distribution provided by the kriging–Lagrangian methodology resulted in overall better streamflow simulations. The early runoff generation related to reduced infiltration rates during early rainfall events features as one of the main reasons for poor LSM performances.
Published: 2017

41. Modeling Surface Runoff and Water Fluxes over Contrasted Soils in the Pastoral Sahel : Evaluation of the ALMIP2 Land Surface Models over the Gourma Region in Mali

Author: Grippa, Manuela, Gal, Laetitia, Anderson, Martha, Ait-Mesbah, S., Polcher, Jan, Balsamo, G., Boussetta, S., Dutra, Emanuel, Pappenberger, F., Hain, Christopher, Boone, Aaron, Favot, F., Guichard, F., Kaptue, A., Roujean, Jean-Louis, Cappelaere, Bernard, Demarty, Jérôme, Peugeot, Christophe, Séguis, L., Velluet, C., Chaffard, V., Cohard, J. M., Gascon, T., Galle, S., Hector, B., Lebel, T., Pellarin, T., Richard, A., Quantin, G., Vischel, T., Chan, E., Verseghy, D., Ducharne, Agnès, Magand, C., Getirana, A., Hiernaux, Pierre, Kergoat, Laurent, Mougin, Éric, Pierre, Caroline, Gusev, Y., Nasonova, O., Harris, P., He, X., Yorozu, K., Kotsuki, S., Tanaka, K., Kim, H., Oki, T., Kumar, S., Lo, M.-H., Mahanama, S., Maignan, F., Ottlé, C., Mamadou, O., Shmakin, A., Sokratov, V., Turkov, D., Working Group, Almip2, Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), United States Department of Agriculture, European Centre for Medium-Range Weather Forecasts (ECMWF), Laboratoire de mesure du carbone 14 (LMC14 - UMS 2572), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Structure et fonctionnement des systèmes hydriques continentaux (SISYPHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE)-MINES ParisTech - École nationale supérieure des mines de Paris-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Météo France-Centre National de la Recherche Scientifique (CNRS), Earth Systems Science Interdisciplinary Center, University of Maryland [College Park], University of Maryland System-University of Maryland System, and Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, 0208 environmental biotechnology, Mesoscale meteorology, 02 engineering and technology, Monsoon, 01 natural sciences, Evapotranspiration, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, 2. Zero hunger, Hydrology, Multidisciplinary analysis, 15. Life on land, [SDE.ES]Environmental Sciences/Environmental and Society, 6. Clean water, 020801 environmental engineering, Water resources, 13. Climate action, Soil water, [SDE]Environmental Sciences, Environmental science, Surface runoff, Surface water
Abstract: Land surface processes play an important role in the West African monsoon variability. In addition, the evolution of hydrological systems in this region, and particularly the increase of surface water and runoff coefficients observed since the 1950s, has had a strong impact on water resources and on the occurrence of floods events. This study addresses results from phase 2 of the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Model Intercomparison Project (ALMIP2), carried out to evaluate the capability of different state-of-the-art land surface models to reproduce surface processes at the mesoscale. Evaluation of runoff and water fluxes over the Mali site is carried out through comparison with runoff estimations over endorheic watersheds as well as evapotranspiration (ET) measurements. Three remote-sensing-based ET products [ALEXI, MODIS, and Global Land Evaporation Amsterdam Model (GLEAM)] are also analyzed. It is found that, over deep sandy soils, surface runoff is generally overestimated, but the ALMIP2 multimodel mean reproduces in situ measurements of ET and water stress events rather well. However, ALMIP2 models are generally unable to distinguish among the two contrasted hydrological systems typical of the study area. Employing as input a soil map that explicitly represents shallow soils improves the representation of water fluxes for the models that can account for their representation. Shallow soils are shown to be also quite challenging for remote-sensing-based ET products, even if their effect on evaporative loss was captured by the diagnostic thermal-based ALEXI. A better representation of these soils, in soil databases, model parameterizations, and remote sensing algorithms, is fundamental to improve the estimation of water fluxes in this part of the Sahel.
Published: 2017

42. Streamflows over a West African Basin from the ALMIP2 model ensemble

Author: Getirana, A., Boone, A., Peugeot, Christophe, ALMIP Working Group, Cappelaere, Bernard, Demarty, Jérome, Séguis, Luc, Velluet, Cecile, Chaffard, Véronique, Galle, Sylvie, Lebel, Thierry, Quantin, Guillaume, and Mougin, Eric
Abstract: Comparing streamflow simulations against observations has become a straightforward way to evaluate a land surface model's (LSM) ability in simulating water budget within a catchment. Using a mesoscale river routing scheme (RRS), this study evaluates simulated streamflows over the upper Oueme River basin resulting from 14 LSMs within the framework of phase 2 of the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Model Intercomparison Project (ALMIP2). The ALMIP2 RRS (ARTS) has been used to route LSM outputs. ARTS is based on the nonlinear Muskingum-Cunge method and a simple deep water infiltration formulation representing water-table recharge as previously observed in that region. Simulations are performed for the 2005-08 period during which ground observations are largely available. Experiments are designed using different ground-based rainfall datasets derived from two interpolation methods: the Thiessen technique and a combined kriging-Lagrangian methodology. LSM-based total runoff (TR) averages vary from 0.07 to 1.97mmday(-1), while optimal TR was estimated as; 0.65mmday(-1). This highly affected the RRS parameterization and streamflow simulations. Optimal Nash-Sutcliffe coefficients for LSM-averaged streamflows varied from 0.66 to 0.92, depending on the gauge station. However, individual LSM performances show a wider range. A more detailed rainfall distribution provided by the kriging-Lagrangian methodology resulted in overall better streamflow simulations. The early runoff generation related to reduced infiltration rates during early rainfall events features as one of the main reasons for poor LSM performances.
Published: 2017

43. Modeling surface runoff and water fluxes over contrasted soils in the pastoral Sahel : evaluation of the ALMIP2 land surface models over the gourma region in Mali

Author: Grippa, M., Kergoat, L., Boone, A., Peugeot, Christophe, Demarty, Jérome, Cappelaere, Bernard, Gal, Laëtitia, Hiernaux, P., Mougin, Eric, Ducharne, A., Dutra, E., Anderson, M., Hain, C., ALMIP Working Group, Séguis, Luc, Velluet, Cecile, Chaffard, Véronique, Galle, Sylvie, Lebel, Thierry, and Quantin, Guillaume
Abstract: Land surface processes play an important role in the West African monsoon variability. In addition, the evolution of hydrological systems in this region, and particularly the increase of surface water and runoff coefficients observed since the 1950s, has had a strong impact on water resources and on the occurrence of floods events. This study addresses results from phase 2 of the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Model Intercomparison Project (ALMIP2), carried out to evaluate the capability of different state-of-the-art land surface models to reproduce surface processes at the mesoscale. Evaluation of runoff and water fluxes over the Mali site is carried out through comparison with runoff estimations over endorheic watersheds as well as evapotranspiration (ET) measurements. Three remote-sensing-based ET products [ALEXI, MODIS, and Global Land Evaporation Amsterdam Model (GLEAM)] are also analyzed. It is found that, over deep sandy soils, surface runoff is generally overestimated, but the ALMIP2 multimodel mean reproduces in situ measurements of ET and water stress events rather well. However, ALMIP2 models are generally unable to distinguish among the two contrasted hydrological systems typical of the study area. Employing as input a soil map that explicitly represents shallow soils improves the representation of water fluxes for the models that can account for their representation. Shallow soils are shown to be also quite challenging for remote-sensing-based ET products, even if their effect on evaporative loss was captured by the diagnostic thermal-based ALEXI. A better representation of these soils, in soil databases, model parameterizations, and remote sensing algorithms, is fundamental to improve the estimation of water fluxes in this part of the Sahel.
Published: 2017

44. The African Database of Hydrometric Indices (ADHI).

Author: Tramblay, Yves, Rouché, Nathalie, Paturel, Jean-Emmanuel, Mahé, Gil, Boyer, Jean-François, Amoussou, Ernest, Bodian, Ansoumana, Dacosta, Honoré, Dakhlaoui, Hamouda, Dezetter, Alain, Hughes, Denis, Hanich, Lahoucine, Peugeot, Christophe, Tshimanga, Raphael, and Lachassagne, Patrick
Subjects: DATABASES, TIME series analysis, SCIENTIFIC community, RIVER conservation
Abstract: The African continent is probably the one with the lowest density of hydrometric stations currently measuring river discharge, despite the fact that the number of operating stations was quite important until the 70s. This new African Database of Hydrometric Indices (ADHI) is compiling data from different sources carefully checked for quality control. It includes about 1500 stations with at least 10 years of daily discharge data over the period 1950-2018. The average record length is 19 years and for over 100 stations complete records are available over 50 years. With this dataset spanning most regions of the African continent, several hydrometric indices have been computed, representing mean flow characteristics and extremes (low flows and floods), and are made accessible to the scientific community. The database will be updated on a regular basis to include more hydrometric stations and longer time series of river discharge. The ADHI database is available for download at: https://doi.org/10.23708/LXGXQ9 (Tramblay and Rouché, 2020). [ABSTRACT FROM AUTHOR]
Published: 2020
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45. Hydrological functioning of western African inland valleys explored with a critical zone model

Author: Hector, Basile, primary, Cohard, Jean-Martial, additional, Séguis, Luc, additional, Galle, Sylvie, additional, and Peugeot, Christophe, additional
Published: 2018
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46. AMMA-CATCH : un observatoire hydrologique, météorologique et écologique de long terme en Afrique de l'Ouest. Résultats importants et données disponibles

Author: Galle, S., Peugeot, Christophe, Grippa, Manuela, Chaffard, Véronique, Afouda, S., Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Transferts dans les Eco-hydrosystèmes (TECHS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)
Subjects: base de données, changement climatique, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, long terme, Observation in situ
Abstract: International audience; AMMA-CATCH est un système d'observation multi-échelle dédié à la surveillance à long terme du cycle de l'eau, ladynamique de la végétation et de leurs interactions avec les ressources en eau en Afrique de l'Ouest. Dans le contexte deschangements globaux, les observations à long terme sont nécessaires pour i) acquérir une compréhension des processus écohydrologiques sur cette région très contrastée, ii) aider à leur représentation dans les modèles du système terrestre, et iii) détecter les tendances pour en déduire leurs impacts sur les ressources en eau et les conditions de vie, et pouvoir ainsi anticiper les risques.L’Observatoire est composé de trois sites à méso-échelle (~ 1 ° x1 °) au Mali, au Niger et au Bénin, s’étendant le long dugradient éco-climatique d’Afrique de l'Ouest. Dans cette fenêtre régionale (5 ° par 9 °), chacun des trois sites documente lescomposantes du bilan hydrologique et les évolutions des conditions de surface: pluie, niveau de la nappe, débit des rivières,humidité et température du sol, flux d’évapotranspiration et de CO2, LAI, biomasse. Au Bénin depuis 2015 certaines stations de mesures sont équipées en télétransmission.Ce système d'observation génère en continu un ensemble de données cohérentes depuis une vingtaine d’années. Il est géré conjointement par des institutions de recherche françaises et Africaines (Mali, Niger et Bénin). La base de données estdisponible à la communauté à travers le site web (www.amma-catch.org). AMMA-CATCH participe à plusieurs réseauxd'observation mondiaux ou régionaux, tels que FluxNet, CarboAfrica, Réseaux d'humidité des sols internationaux (ISMN) etaux campagnes de calibration-validation (CAL-VAL) pour les missions satellites comme SMOS (Europe / France / Espagne), Megha-Tropiques (France / Inde) ou SWAP (NASA). Les résultats récents de la recherche menée sur notre observatoire sont présentés suivant 3 axes : la dynamique régionale de long terme, les processus éco-hydrologiques et les applications pour la société et le développement.Au Bénin les résultats principaux de l’observatoire AMMA-CATCH portent sur les bilans de flux et de carbone qui n’avaientencore jamais été mesurés dans cette région, le rôle des réservoirs souterrains et des arbres (ripisylves, forêts) dans lefonctionnement hydrologique et la caractérisation hydrogéophysique des stocks d’eau souterrains en zone de socle. Lesdonnées de l'observatoire ont également permis l'évaluation de produits issus de missions satellitaires (SMOS - humidité dusol et Megha Tropiques - pluies), et la modélisation du cycle hydrologique continental pour la gestion intégrée des ressources en eau (GIRE). Les données télétransmises contribueront aux programmes d’alerte précoce contre les inondations.
Published: 2016

47. AMMA-CATCH : un observatoire hydrologique, météorologique et écologique de long terme en Afrique de l'Ouest : résultats importants et données disponibles

Author: Galle, Sylvie, Peugeot, Christophe, Grippa, M., Chaffard, Véronique, Afouda, S., Agbossou, E.K., Ago, E.E., Arjounin, Marc, Awessou, B., Boucher, Marie, Boukari, M., Cohard, J.M., Doussou, M., Descloître, Marc, Gosset, Marielle, Hector, B., Lawin, E., Mamadou, O., Mason, E., Ouani, T., Richard, A., Seghieri, Josiane, Séguis, Luc, Velluet, Cécile, Vouillamoz, Jean-Michel, Wubda, M., Yalo, N., and Zannou, A.
Subjects: FORET, COUVERT VEGETAL, BILAN HYDRIQUE, PLUVIOMETRIE, METEOROLOGIE, PROGRAMME DE RECHERCHE, RESSOURCES EN EAU, EAU SOUTERRAINE, INTERNET, TEMPERATURE, EAU DE SURFACE, COOPERATION SCIENTIFIQUE, BIOMASSE, EVAPOTRANSPIRATION, DONNEES SATELLITE, HUMIDITE DU SOL, BASE DE DONNEES, MODELISATION, CARBONE, MESURE AU SOL, PREVISION, BILAN HYDROLOGIQUE, CHANGEMENT CLIMATIQUE, ACCES LIBRE, OBSERVATOIRE, ECOLOGIE
Published: 2016

48. Impact of Deforestation on Water Budget in Sudanian Climate (Benin)

Author: Mamadou, O., Galle, S., Cohard, J.M., Peugeot, Christophe, Ntiwunwa, J.D., Laboratoire d'étude des transferts en hydrologie et environnement (LTHE), Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Transferts dans les Eco-hydrosystèmes (TECHS), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)
Subjects: Impacts of global change, Biodiversity, Water cycles, Hydrology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, Biogeosciences, Anthropogenic effects, Global change
Abstract: International audience; In West Africa, surface atmosphere exchanges have been found to impact both regional and local features of the Monsoon. At local scale the spatial patterns of evaporative fraction can drive the trajectories of mesoscale convective systems. Within Sudanian climate, ~80% of the precipitation returns to atmosphere through evapotranspiration. However, this amount and its seasonal dynamic may vary with the vegetation cover. Consequently, one might expect that any land use or climate changes could lead to the modification of the surface feedbacks, and, thus on both the atmospheric and the continental water cycle. The sudanian region of West Africa is submitted to a 3% demographical increase per year, which induces a drastic expansion of crops areas. In the Upper Oueme basin, the natural forest cover reduces from 70% to 25% in 40 years. This study aims at quantifying the changes in evapotranspiration regime caused by such a land use change under sudanian climate. The AMMA-CATCH observatory documents evapotranspiration flux in West Africa since 2007. A pluri-annual energy budget of a forest and a cropland area are analysed. It is shown that sudanian forest evapo-transpirated always more than cropland areas because of agricultural practice and water availability for trees. Thus, during the dry season, the cropland areas are bare while the forests do not completely lose their leaves. Their deep root systems allow the trees to get access to water. Observed evapotranspiration is significant over forests. During the rainy season, vegetation is fully developed and well-watered. Nevertheless, lower but significant differences in evaporative fraction are also observed. At annual scale these differences lead to a 13% to 30% reduction of evapotranspiration with deforestation.
Published: 2015

49. Is agroforestry species as efficient as forest species in recycling local rainfall in sudanian belt?

Author: Awessou, B., Peugeot, Christophe, Seguis, L., Galle, S., Rocheteau, A., Do, FC., Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Transferts dans les Eco-hydrosystèmes (TECHS), and Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2015

50. Impact of deforestation on surface water and energy feedbacks in sudanian region of West Africa

Author: Mamadou, O., Galle, S., Cohard, J.M., Peugeot, Christophe, Seghieri, Josiane, Kounouhewa, Basile, O, Mamadou, Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Transferts dans les Eco-hydrosystèmes (TECHS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Département Environnement et Ressources [Montpellier] (ESPACE-DEV), Université des Antilles et de la Guyane (UAG)-Université de La Réunion (UR)-Université de Montpellier (UM), Entomologie fonctionnelle et évolutive - Université de Liège, Université de Liège - Gembloux, and Université de Montpellier (UM)-Université de La Réunion (UR)-Université des Antilles et de la Guyane (UAG)
Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract: International audience; In West Africa, surface atmosphere exchanges have been found to impact both regional and local features of the Monsoon. At local scale the spatial patterns of evaporative fraction can drive the trajectories of mesoscale convective systems. Within Sudanian climate, ~80% of the precipitation returns to atmosphere through evapotranspiration. However, this amount and its seasonal dynamic may vary with the vegetation cover. Consequently, one might expect that any land use or climate changes could lead to the modification of the surface water and energy feedbacks, and, thus both the atmospheric and the regional water cycle. Finally, the sudanian region of West Africa is submitted to a 3% demographical increase per year, which induces a drastic expansion of crops areas. This study aims at quantifying the changes in evapotranspiration and sensible heat flux regimes caused by such a land use change under sudanian climate.The AMMA-CATCH observatory documents evapotranspiration flux in West Africa since 2007. A pluri-annual energy budget term of a clear forest and a cropland area are analysed. It is shown that sudanian forest evapo-transpirated always more than crop areas because of agricultural practice, which cleaned to bare the crops areas with bush fires and water availability for trees. Thus, during the dry season, the cultivated areas remain bare. At the same time, more than 1mm per day of evapotranspiration rate is measured above the forest area despite the lack of precipitations. Deep rooting systems allow the clear forest to get access to water from deep soil layers for transpiration throughout the dry season. During the rainy season, low but significant differences in evaporative fraction are also observed. These differences will lead to a large deficit of the water vapour that returns to the atmosphere, and, thus, will change significantly the continental water cycle when forests will be replaced by crops. In the future, agroforestry that combines local crops (yam, manioc, millet, etc.) and sparse trees could mitigate surface feedbacks. Finally, the selected trees could provide extra agricultural products taking benefit from deep water availability, but also strengthen social equilibrium between men and women.
Published: 2015

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