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4. Aerosol and Rain Chemistry in the Marine Environment

Author

Colin, J. L., Losno, R., Le Bris, N., Tisserant, M., Vassali, I., Madec, S., Cholbi, S., Vimeux, F., Bergametti, G., Cachier, H., Liousse, C., Ducret, J., Lim, B., Pertuisot, M. H., Menard, P. Buat, Jickells, T., Spokes, L., Jennings, G., Schulz, Michael, Rebers, A., Maenhaut, W., Francois, F., Grieken, R. V., Injuk, J., Borrell, Peter, editor, Borrell, Patricia M., editor, Midgley, Pauline, editor, Larsen, Søren E., editor, and Fiedler, Franz, editor

Published
2000
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6. Rain, Wind, and Dust Connections in the Sahel

Author

Bergametti, G., primary, Rajot, J.‐L., additional, Marticorena, B., additional, Féron, A., additional, Gaimoz, C., additional, Chatenet, B., additional, Coulibaly, M., additional, Koné, I., additional, Maman, A., additional, and Zakou, A., additional

Published
2022
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9. A 3d Regional Scale Photochemical Air Quality Model. Application to a 3 Day Summertime Episode over Paris Un modèle photochimique 3D de qualité de l'air à l'échelle régionale. Application à un épisode de 3 jours à Paris en été

Author

Carissimo B., Dupont E., Musson-Genon L., Riboud P. M., Jaecker-Voirol A., Lipphardt M., Martin B., Quandalle Ph., Salles J., Aumont B., Bergametti G., Bey I., and Toupance G.

Subjects
Chemical technology, TP1-1185, Energy industries. Energy policy. Fuel trade, HD9502-9502.5
Abstract

This paper presents AZUR, a 3D Eulerian photochemical air quality model for the simulation of air pollution in urban and semi-urban areas. The model tracks gas pollutant species emitted into the atmosphere by transportation and industrial sources, it computes the chemical reactions of these species under varying meteorological conditions (photolysis, pressure, temperature, humidity), their transport by wind and their turbulent diffusion as a function of air stability. It has a modular software structure which includes several components dedicated to specific processes :-MERCURE, a meso-scale meteorological model to compute the wind field, turbulent diffusion coefficients, and other meteorological parameters. It is a 3D regional scale model accounting for different ground types and urban densities. It includes a complete set of physical parameterizations in clear sky. -MIEL, an emission inventory model describing the pollutant fluxes from automotive transportation, domestic and industrial activities. This model includes a mobile source inventory based on road vehicle countings together with global information on transportation fluxes extracted from statistical population data. It uses specific emission factors representative of the vehicle fleet and real driving patterns. -MoCA a photochemical gas phase model describing the chemistry of ozone, NOx, and hydrocarbon compounds. This model, with 83 species and 191 reactions, is a reduced mechanism well adapted to various air quality conditions (ranging from urban to rural conditions). For interpretative reasons, the identity of primary hydrocarbons is preserved. -AIRQUAL, a 3D Eulerian model describing the transport by mean wind flux and air turbulent diffusion of species in the atmosphere, associated with a Gear type chemical equation solver. The model has been applied to a 3-day summertime episode over Paris area. Simulation results are compared to ground level concentration measurements performed by the local monitoring network (Airparif). Cet article présente AZUR, un modèle photochimique eulérien 3D de qualité de l'air pour la simulation de la pollution de l'air dans les zones urbaines et semi-urbaines. Ce modèle suit les évolutions des espèces polluantes gazeuses émises dans l'atmosphère par les transports routiers et les sources industrielles, il prend en compte les réactions chimiques auxquelles sont soumises ces espèces pour des conditions météorologiques en évolution (photolyse, pression, température, humidité), leur transport par le vent et leur diffusion turbulente en fonction de la stabilité de l'air. Le logiciel a une structure modulaire avec plusieurs composants dédiés à des processus spécifiques : -MERCURE est un modèle météorologique à moyenne échelle pour déterminer les champs de vents, les coefficients de diffusion turbulente et d'autres paramètres météorologiques. C'est un modèle 3D à l'échelle régionale qui prend en compte les différentes configurations de sols et les zones de densité urbaine. Il comprend un système complet de paramètres physiques associés à des situations de ciel dégagé. -MIEL est un modèle d'inventaire d'émissions décrivant les flux de polluants provenant des transports automobiles et des activités domestiques ou industrielles. Ce modèle comprend un inventaire des sources mobiles basé sur des comptages de véhicules sur routes associés à des informations globales sur les flux de transports déduites de données statistiques sur la population. Il utilise des facteurs d'émission spécifiques correspondant aux flottes de véhicules et à des conditions de conduites réalistes. -MoCA est un modèle photochimique en phase gazeuse décrivant la chimie de l'ozone, des NOx, et des composés hydrocarbonés. Ce modèle, avec 83 espèces et 191 réactions, correspond à un mécanisme réduit bien adapté à des conditions variées de qualité de l'air (allant de conditions en sites urbains à celles en sites ruraux). Pour des raisons de commodité d'interprétation, l'identité des hydrocarbures primaires est conservée. -AIRQUAL est un modèle eulérien 3D décrivant les phénomènes de transport par les vents et la diffusion turbulente des espèces dans l'atmosphère, il est associé à un solveur d'équations chimiques du type Gear. Le modèle a été appliqué à un épisode estival de 3 jours au-dessus de la région parisienne. Les résultats de la simulation sont comparés aux mesures de concentrations opérées par le réseau local de surveillance (Airparif).

Published
2006
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10. Comparison between Eddy-Covariance and Flux-Gradient size-resolved dust fluxes during wind erosion events

Author

Dupont, Sylvain, Rajot, J-L, Lamaud, E, Bergametti, G, Labiadh, M, Khalfallah, B, Bouet, C, Marticorena, B, Fernandes, R, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences
Abstract

International audience; Estimating accurately dust emission flux during aeolian erosion events is crucial forquantifying the amount of dust in the atmosphere. The rare existing field experiments quantifyingsuch flux were mainly performed using the flux-gradient (FG) method. Here, we present the firstintercomparison of the size-resolved dust fluxes estimated by both the FG and the eddy-covariance (EC)methods during several erosion events. Both methods were applied simultaneously during the WINDO-V (WIND erOsion in presence of sparse Vegetation)'s 2017 field experiment over an isolated erodiblebare plot in South Tunisia. Overall, both methods predict similar dust fluxes for particle smaller thanabout 4 μm. For coarser particles, the EC method predicts a smaller dust flux than the FG method. Factorsexplaining this difference are discussed such as the different sampling heads used by the dust particlecounters of both methods, or the possible weakening of the constant dust flux layer at the location ofthe upper dust particle counter of the FG method. This intercomparison highlights the difficulties andadvantages of each method as well as their complementarity.

Published
2021

13. LA STABILITÉ ATMOSPHÉRIQUE INFLUENCE-T-ELLE LA DISTRIBUTION EN TAILLE DU FLUX VERTICAL DE POUSSIÈRE ? PREMIERS RÉSULTATS EN CONDITIONS D'ÉROSION

Author

B. KHALFALLAH, BOUET, C., LABIADH, M.T., ALFARO, S.C., BERGAMETTI, G., MARTICORENA, B., LAFON, S., CHEVAILLIER, S., FÉRON, A., HEASE, P., HENRY DES TUREAUX, T., SEKRAFI, S., ZAPF, P., and RAJOT, J.L.

Subjects
Érosion éolienne, Size-resolved dust flux, Atmospheric stability, Gradient method, Distribution en taille des aérosols désertiques, Stabilité atmosphérique, Wind erosion, Méthode du gradient
Abstract

La distribution en taille des aérosols désertiques est un élément-clef pour quantifier leurs impacts tout au long de leur cycle. Cependant, peu de mesures in-situ existent aujourd’hui pour caractériser cette propriété à l’émission. Ce travail présente les flux d’émission résolus en taille mesurés au cours de 8 événements érosifs dans le sud tunisien. La méthode employée est celle dite « du gradient ». Le principal résultat est qu’en condition d’érosion, la distribution en taille du flux vertical d’aérosols désertiques est plus riche en particules submicroniques pendant les périodes thermiquement instables., The size distribution of desert dust is a key factor to quantify its impacts during its life cycle. However, only a few in-situ measurements are currently available to document this feature at emission. This study presents the measurements of the size-distribution of the dust emission flux made during 8 erosive events using the gradient method over an experimental plot located in southern Tunisia. The main result is that in eroding conditions the number size-distribution of the dust flux is significantly enriched in submicron particles during thermally unstable periods.

Published
2020
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14. The respective roles of wind speed and green vegetation in controlling Sahelian dust emission during the wet season

Author

Bergametti, G., Marticorena, B., Rajot, Jean-Louis, Feron, A., Gaimoz, C., Coman, A., Chatenet, B., Coulibaly, M., Maman, A., Kone, I., and Zakou, A.

Subjects
complex mixtures, respiratory tract diseases
Abstract

Based on 10 years of continuous measurements of wind speed, rainfall, and PM10 concentrations (i.e., concentrations of the particulate matter having a diameter lower than 10 mu m) performed in two Sahelian stations, we examine how wind speed and vegetation interact during the wet season to control the dust concentration when it is due to local dust emissions. The results clearly show that the frequency of the high wind speeds is higher at the beginning of the wet season and is the main driver of the seasonal dust emission. During the second part of the wet season, the frequency of high wind speeds is much lower and, in addition, their efficiency for wind erosion and dust emission is strongly affected by the vegetation whose growth reduces progressively PM10 concentrations up to 80%.

Published
2020

19. Influence of Atmospheric Stability on the Size Distribution of the Vertical Dust Flux Measured in Eroding Conditions Over a Flat Bare Sandy Field

Author

Khalfallah, B., primary, Bouet, C., additional, Labiadh, M.T., additional, Alfaro, S.C., additional, Bergametti, G., additional, Marticorena, B., additional, Lafon, S., additional, Chevaillier, S., additional, Féron, A., additional, Hease, P., additional, Henry des Tureaux, T., additional, Sekrafi, S., additional, Zapf, P., additional, and Rajot, J.L., additional

Published
2020
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21. Dissimilarity between dust, heat, and momentum turbulent transports during aeolian soil erosion

Author

Dupont, S., Rajot, J.-L, Labiadh, M., Bergametti, G., Lamaud, E., Irvine, M., Alfaro, S., Bouet, C., Fernandes, R., Khalfallah, B., Marticoréna, B., Bonnefond, J., Chevaillier, S., Garrigou, D., Henry-Des-Tureaux, T, Sekrafi, S., Zapf, P., Rajot, J.‐L., Henry‐des‐Tureaux, T., Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), 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)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut des Régions Arides (IRA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), ANR WIND-O-V, Institut d’Électronique, de Microélectronique et de Nanotechnologie (IEMN) - UMR 8520 (IEMN), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Université Polytechnique Hauts-de-France (UPHF)-Ecole Centrale de Lille-Université Polytechnique Hauts-de-France (UPHF)-Institut supérieur de l'électronique et du numérique (ISEN), Institut des Régions Arides de Médenine (IRA), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Unité de bioclimatologie, Institut National de la Recherche Agronomique (INRA), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Laboratoire de Météorologie Physique - Clermont Auvergne (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Interactions Sol Plante Atmosphère (ISPA), Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro)-Institut National de la Recherche Agronomique (INRA), Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) ), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS), Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen (GREYC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de recherche en Hydrodynamique, Énergétique et Environnement Atmosphérique (LHEEA), École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and 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)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Eddy covariance, Astrophysics::Cosmology and Extragalactic Astrophysics, Atmospheric sciences, 01 natural sciences, law.invention, TUNISIA, Flux (metallurgy), law, Intermittency, Saltation (geology), Earth and Planetary Sciences (miscellaneous), Astrophysics::Solar and Stellar Astrophysics, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, [PHYS]Physics [physics], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, SEMIARID AREA, Turbulence, 15. Life on land, Geophysics, Heat flux, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Erosion, Aeolian processes, Environmental science, Astrophysics::Earth and Planetary Astrophysics, 068, 020
Abstract

International audience; Measuring accurately size-resolved dust flux near the surface is crucial for better quantifying dust losses by semiarid soils. Dust fluxes have been usually estimated from the flux-gradient approach, assuming similarity between dust and momentum turbulent transport. This similarity has, however, never been verified. Here we investigate the similarity between dust (0.3 to 6.0 m in diameter), momentum, and heat fluxes during aeolian erosion events. These three fluxes were measured by the Eddy Covariance technique during the WIND-O-V (WIND erOsion in presence of sparse Vegetation's) 2017 field experiment over an isolated erodible bare plot in South Tunisia. Our measurements confirm the prevalence of ejection and sweep motions in transporting dust as for heat and momentum. However, our measurements also reveal a different partition of the dust flux between ejection and sweep motions and between eddy time scales compared to that of momentum and heat fluxes. This dissimilarity results from the intermittency of the dust emission compared to the more continuous emission (absorption) of heat (momentum) at the surface. Unlike heat emission and momentum absorption, dust release is conditioned by the wind intensity to initiate sandblasting. Consequently, ejection motions do not carry dust as often as heat and low momentum from the surface. This dissimilarity diminishes with increasing wind intensity as saltation patterns, and thus dust emission through sandblasting, become spatially more frequent. Overall, these findings may have implications on the evaluation of dust flux from techniques based on similarity with momentum or heat turbulent transport.

Published
2019

26. The WIND-O-V field experiment: WIND erOsion in presence of sparse Vegetation

Author

Rajot, Jean Louis, Bergametti, G., Labiadh, Mohamed, Alfaro, S., Bonnefond, J. -M., Bouet, Christel, Chevaillier, Servanne, Fernandes, Royston, Feron, Anais, Garrigou, Didier, Guillet, Anne-Charlotte, Hease, Patrick, Henri Des Tureaux, Thierry, Khalfallah, B., Lafon, Sandra, Lamaud, Eric, Laurent, Benoit, Ltifi, Mohsen, Marticorena, Beatrice, Pierre, Caroline, Sekrafi, Saâd, Zapf, Pascal, Dupont, Sylvain, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut des Régions Arides (IRA), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut des Régions Arides, and bergametti, gilles

Subjects
[SDE] Environmental Sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Eddy covariance method, Saltation, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDE.MCG]Environmental Sciences/Global Changes, Chemical composition, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, Dust emission, [SDU] Sciences of the Universe [physics], [SDE.MCG] Environmental Sciences/Global Changes, Gradient method, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Size-resolved fluxes, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Wind erosion in semiarid areas is a major threat for the soil productivity as it impoverishes soil in organic matters and nutrients. Compared to desert regions, these regions are characterized by sparse seasonal vegetation that impacts the erosion process. Semiarid areas face two major evolutions that may modify their wind soil erosion in the future: (1) climate change, with a modification of the amplitude and frequency of precipitations, affecting the surface vegetation cover, and (2) population growth, generating a considerable human pressure on the land use. Characterizing wind erosion in such complex regions is, therefore, crucial and challenging. In order to better predict the amount and composition of emitted dust from semiarid areas, a novel field experiment named WIND-O-V (wind erosion in presence of sparse vegetation) has been performed in 2017 and 2018 in South Tunisia. The originality of this experiment is (1) to cover successively a plot without and with sparse vegetation, and (2) to combine detailed measurements of wind dynamics (including turbulence), size-resolved saltation and dust fluxes, and erosion-flux compositional fractionation along the soil-saltation-suspension continuum. The experiment took place from March to May in the experimental range of the Institut des Régions Arides (IRA) of Médenine (Dar Dhaoui, 25 km east of Médenine). The site approximates a flat half-circle plot of 150 m radius where measurements were performed at the center of the circle in order to ensure a fetch of at least 150 m. In 2017, the surface has been tilled with a disc plough and levelled with a wood board in order to meet the conditions of an ideal flat bare soil without soil crust or ridges. In 2018, sparse vegetation consisting of barley tufts have been grown on the plot with a 3.3 m wide regular arrangement. Three types of measures were carried out. Meteorology: on a 9 m high mast erected at the center of the plot, turbulent velocity components and air temperature fluctuations were measured simultaneously at 1.0, 1.9, 3.0, and 4.1 m height using four 3D sonic anemometers sampling at 60, 50, 50, and 20 Hz, respectively. On the same mast, 7 cup anemometers (0.2, 0.6, 1.3, 1.8, 3.0, 4.0, 5.2 m) and 4 thermocouples (0.4, 1.6, 3.7, 5.0 m) were also installed to measure simultaneously at 0.1 Hz the mean horizontal wind velocity and temperature profiles, respectively. Three additional 2D sonic anemometers were installed in 2018 around a barley tuft to characterize the wind around the vegetation. Roughness length of the surface and friction velocity were computed on the bare plot case by comparing the Law-of-the-wall and Eddy-Covariance methods. Saltation flux: one vertical array of 5 sediment traps like Big Spring Number Eight (BSNE) was deployed to quantify the saltation flux and its size distribution. The modified BSNE had a 5 times wider opening area to collect larger sediment quantities, allowing sequential (in time) sampling of individual erosive events and guarantying the possibility of applying size resolved analyses. Saltation flux measurements with a better temporal resolution were thus associated with more stable friction velocity conditions. In 2018, 5 MWAC masts were added to measure the spatial variability of the flux due to the sparse vegetation. A Saltiphone and a camera gave information on the beginning, end, and duration of erosive events. Dust flux: for the first time size-resolved dust fluxes were estimated from both the traditional flux-gradient approach and the eddy covariance approach. For the first approach, mass and size resolved number concentrations were measured at two levels (2 and 4 m). To that purpose, two TEOM microbalances and two optical particle counters (WELAS Promo 2300) were used. Both sensor-types were connected to omnidirectional air sampling inlets. The WELAS monitored at 1 Hz the dust concentrations per size class (32 classes between 0.3 and 17 μm). For the second approach, a third WELAS was coupled to the 3 m high sonic anemometer in order to correlate the size-resolved dust concentration and the vertical wind velocity fluctuations. Finally, the chemical composition of dust fluxes was estimated from the sequential sampling of dust particles at two levels (2 and 4 m) with online filters equipped with inlets of different size cutoffs (20, 10, 2.5 and 1 μm).

Published
2018

27. Size-resolved deposition fluxes and deposition velocities over a sandy surface: In-situ experimental determination and comparison with existing parameterizations

Author

Bergametti , G, Marticorena, Beatrice, Rajot, J-L., Foret, Gilles, Alfaro, Stephane C., Laurent, Benoit, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and bergametti, gilles

Subjects
[SDU] Sciences of the Universe [physics], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU]Sciences of the Universe [physics], [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Key words dust dry deposition, measurements, test of parameterizations An intense dust deposition event occurred in June 2006 in Niger. It was the consequence of the turn-back of a dust cloud resulting from a large wind erosion event that occurred the day before due to the passage of a mesoscale convective system. Bulk and size resolved particle concentrations were measured at 2.1 and 6.5 m over an agricultural field. At the date of the experiment (mid-June), almost all the vegetative residues from the previous year were decomposed or grazed and the sandy surface was almost bare, with only few percents of residues remaining. In the wind direction, the fetch was greater than 500 m. Bulk concentrations measurements were performed using two TEOM instruments and size resolved particle concentrations in 15 channels (from 0.3 µm to 20 µm) using two Optical Particle Counters (OPC, GRIMM instruments). These instruments have been carefully cross-calibrated before the campaign. At each level, the particle concentrations from TEOM and the particle volume from OPC were highly correlated with a slope 2.265 (+/-0.02) which is the apparent mass density of the particles. In complement wind and temperature profiles were measured at 5 and 4 different heights, respectively. The stability conditions remained near-neutral (-0.05

Published
2018

28. Impact of land use on wind erosion and dust emission in the Sahel: a regional modelling approach

Author

Marticorena, Beatrice, Siour, Guillaume, Pierre, Caroline, Bouet, Christel, Bergametti, G., Abdourhamane Touré, A., Baron, Christian, Bouniol, Dominique, Couvreux, Fleur, Guichard, Francoise, Grippa, Manuela, Hiernaux, Pierre, Kergoat , Laurent, Largeron, Yann, Lebel, Thierry, Mougin, Éric, Quantin, Guillaume, Rajot, J.L., Roussillon, Joana, Tidjani, Adamou Didier, Valentin, Christian, Vischel, T., Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and bergametti, gilles

Subjects
[SDE] Environmental Sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Vegetation, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDE.MCG]Environmental Sciences/Global Changes, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, Dust emission, [SDU] Sciences of the Universe [physics], [SDE.MCG] Environmental Sciences/Global Changes, [SDU]Sciences of the Universe [physics], Sahel, Wind erosion, Land use, [SDE]Environmental Sciences, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; The semi-arid Sahelian region is particularly prone to wind erosion due to low and variable precipitation rates producing low vegetation cover with a high interannual variability. Surfaces traditionally devoted to pasture are progressively turned to cultivated fields increasing the proportion of bare surface unprotected from wind erosion. Wind erosion could significantly evolve in the future due to climate change and to the increase in crop areas due to the growing population. To estimate the wind erosion and dust emission in the Sahel, we have developed a regional modelling approach in the frame of the CAVIARS project (Climate, Agriculture and Vegetation: Impacts on Aeolian eRosion in the Sahel). The approach is based on existing models that were adapted, improved and coupled to represent the main processes involved in the wind erosion and their dependence to climate parameters and agricultural practices. Natural vegetation (herbaceous) and cultivated vegetation (millet) are respectively modelled with the STEP vegetation model (Mougin et al., 1995) and the SARRA-H agronomic model (Baron et al., 2005). Both models have been improved to reproduce the dynamics of dry vegetation and to produce multi-annual simulations (e.g. Pierre et al., 2016). The wind erosion model (Marticorena and Bergametti, 1995) has been tested and adapted to represent the erosion fluxes over typical Sahelian vegetated surfaces (Pierre et al., 2014a, b). Surface crusting and its dynamics is represented as a function of soil texture, precipitation and vegetation cover. A main limitation was to represent the very high surface winds associated to the convective activity that are not reproduced by the large scale meteorological wind fields (Largeron et al., 2015). A specific parameterization of the distribution of the surface wind speeds have been developed based on high resolution simulations (CASCADE exercise). The application of the models at the regional scale required dedicated data sets, established for this purpose. Daily precipitation fields have been produced based on local measurements and grazing pressure maps have been established based on national data and/or agro-poastoral census. The proportion of cultivated fields and pastured lands are derived from the Sahelian land use map of the AGRHYMET (Tappan et al., 2004). The spatial and temporal distribution of the simulated dust emissions computed from the period 2000-2014 will be presented. The parameterization of the wind speed distribution associated with the convective activity allows to better capture the seasonal pattern of local wind erosion (Bergametti et al., 2017). The relative weight of climatic parameters, vegetation and cultivation will be estimated by comparing regional simulations with and without vegetation and cultivation. References

Published
2018

29. Aerodynamic Parameters Over an Eroding Bare Surface: Reconciliation of the Law of the Wall and Eddy Covariance Determinations

Author

Dupont, S., Rajot, J-L, Labiadh, M., Bergametti, G., Alfaro, S., Bouet, C., Fernandes, R., Khalfallah, B., Lamaud, E., Marticoréna, B., Bonnefond, J-M, Chevaillier, S., Garrigou, D., Henry-des-Tureaux, T., Sekrafi, S., Zapf, P., Rajot, J-L., Bonnefond, J-M., Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) ), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut des Régions Arides de Médenine (IRA), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS), Institut d’Électronique, de Microélectronique et de Nanotechnologie (IEMN) - UMR 8520 (IEMN), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Université Polytechnique Hauts-de-France (UPHF)-Ecole Centrale de Lille-Université Polytechnique Hauts-de-France (UPHF)-Institut supérieur de l'électronique et du numérique (ISEN), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Physique - Clermont Auvergne (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Unité de bioclimatologie, Institut National de la Recherche Agronomique (INRA), IWMI-SFRI, Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie]), Interactions Sol Plante Atmosphère (UMR ISPA), Institut des Régions Arides (IRA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), 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)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire de recherche en Hydrodynamique, Énergétique et Environnement Atmosphérique (LHEEA), École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS), Lieux, Identités, eSpaces, Activités (LISA), Centre National de la Recherche Scientifique (CNRS)-Université Pascal Paoli (UPP), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and Université Pascal Paoli (UPP)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Eddy covariance, Von Kármán constant, 01 natural sciences, Law of the wall, Wind speed, 010305 fluids & plasmas, Saltation (geology), 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Surface roughness, Shear velocity, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS]Physics [physics], Mechanics, 021, 020, 068, Geophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Aeolian processes, Geology
Abstract

International audience; Assessing accurately the surface friction velocity is a key issue for predicting and quantifying aeolian soil erosion. This is usually done either indirectly from the law of the wall (LoW) of the mean wind velocity profile or directly from eddy covariance (EC) of the streamwise and vertical wind velocity fluctuations. However, several recent experiments have reported inconsistency between friction velocities deduced from both methods. Here we reinvestigate the determination of aerodynamic parameters (friction velocity and surface roughness length) over an eroding bare surface and look at the possible reasons for observing differences on these parameters following the method. For that purpose a novel field experiment was performed in South Tunisia under the research program WIND-O-V (WIND erOsion in presence of sparse Vegetation). We find no significant difference between friction velocities obtained from both law of the wall and EC approaches when the friction velocity deduced from the EC method was extrapolated to the surface. Surface roughness lengths show a clear increase with wind erosion, with more scattered values when deduced from the EC friction velocity. Our measurements further suggest an average value of the von Karman constant of 0.407±0.002, although individual wind events lead to different average values due probably to the definition of the ground level or to the stability correction. Importantly, the von Karman constant was found independent of the wind intensity and thus of the wind soil erosion intensity. Finally, our results lead to several recommendations for estimating the aerodynamic parameters over bare surface in order to evaluate saltation and dust fluxes.

Published
2018

31. Dust Uplift Potential in the Central Sahel: An Analysis Based on 10 years of Meteorological Measurements at High Temporal Resolution

Author

Bergametti, G., Marticoréna, B., Rajot, J., Chatenet, B., Féron, A., Gaimoz, C., Siour, G., Coulibaly, M., Koné, I., Maman, A., Zakou, A., Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers EFLUVE, French national program [AMMA-2], French Agence Nationale de la Recherche (ANR) [ANR-12-SENV-0007-01], and Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, congenital, hereditary, and neonatal diseases and abnormalities, [SDU]Sciences of the Universe [physics], Sahel, [SDE]Environmental Sciences, wind, dust, erosion, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; A 10 year data set of wind speed and precipitation recorded in two Sahelian stations located in Niger and Mali is used to investigate the duration and the diurnal and seasonal cycles of high wind speeds and Dust Uplift Potential (DUP). The results indicate that high wind speeds, those greater than the threshold wind velocity required to initiate wind erosion (TWV) over a bare soil occurred in the middle and late morning during the dry and wet seasons but also at nighttime during the wet season. However, the morning wind speeds are only slightly greater than TWV leading to low DUP. On the opposite, the high wind velocities associated to the nocturnal mesoscale convective systems crossing the Sahel during the wet season are responsible for the highest potential wind erosion events. This leads to a strong seasonality of DUP with more than 70% occurring in less than 90 days, from mid-April to mid-July. The duration of the high wind speed events is very short since more than 80% last for less than 3 h, suggesting that the frequency of the observations performed in SYNOP meteorological stations is not sufficient to correctly quantify the contribution of such events to DUP. Finally, by combining precipitation and DUP, we estimated that precipitation should have a relatively limited role in terms of inhibition of wind erosion in this region with precipitation only affecting 25% of total DUP.

Published
2017

33. Mineral dust over west and central Sahel: Seasonal patterns of dry and wet deposition fluxes from a pluriannual sampling (2006-2012)

Author

Chatenet, B., Rajot, Jean-Louis, Bergametti, G., Deroubaix, A., Vincent, J., Kouoi, A., Schmechtig, C., Coulibaly, M., Diallo, A., Kone, I., Maman, A., NDiaye, T., Zakou, A., and Marticorena, B.

Subjects
parasitic diseases
Abstract

Total and wetmineral dust deposition has beenmonitored since 2006 at three Sahelian stations in Senegal, Mali, and Niger, respectively at the weekly and the event time scale. Average annual deposited mass fluxes range from 75 to 183 gm(-2) yr(-1), from west to east. Deposition fluxes exhibit a clear seasonal cycle in Mali and Niger. High wet deposition fluxes result from an optimum phasing between dust concentration and precipitation: the maximum occurring at the beginning of the wet season, after the maximum of dust concentration and before the precipitation maximum. The contribution of wet to total deposition varies from 67% in Mali to 8% in Senegal. It is the main factor of variability of the deposition fluxes from year to year and at the seasonal scale in Niger and Mali. Wet deposition fluxes in Mali and Niger are mainly due to the wash out of dust emitted by convective systems. In Senegal, the deposition fluxes are lower and dominated by dry deposition (92% of the annual deposition flux). This is due to the low occurrence of convective systems producing local dust emissions and intense wet deposition. The dry deposition fluxes are primarily driven by the variability of the dust concentration. The dry deposition velocities derived from our measurements are consistent with those estimated by theoretical models. Scavenging ratios computed from the measured wet deposition fluxes, dust concentrations, and precipitation are anticorrelated with precipitation amounts. This suggests that most of the atmospheric dust is scavenged at the very beginning of the precipitation events.

Published
2017

34. Mineral dust over west and central Sahel: Seasonal patterns of dry and wet deposition fluxes from a pluriannual sampling (2006-2012)

Author

Marticoréna, B., Chatenet, B., Rajot, Jean-Louis, Bergametti, G., Deroubaix, A., Vincent, J., Kouoi, A., Schmechtig, C., Coulibaly, M., Diallo, A., Kone, I., Maman, A., Ndiaye, T., Zakou, A., Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Institut d'écologie et des sciences de l'environnement de Paris (iEES), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), SRAC, Institut d'Economie Rurale, US191 Instrumentation, Moyens Analytiques, Observatoires en Géophysique et Océanographie (IMAGO), Institut de Recherche pour le Développement (IRD [France-Ouest]), European Community's Sixth Framework Research Programme, Observatoire des Sciences de l'Univers EFLUVE, French national program [AMMA-2], DRUMS (DeseRt dUst Modeling: performance and Sensitivity evaluation) research program - ASTRID fund call of the French Agence Nationale de la Recherche (ANR) [ANR-ASTRID-DRUMS-2012], Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Laboratoire de mécanique Biomécanique Polymère Structures (LaBPS), Université de Lorraine (UL), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Instrumentation, Moyens analytiques, Observatoires en Géophysique et Océanographie (IMAGO), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS), Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) ), École normale supérieure - Paris (ENS Paris)-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 Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Institut d'écologie et des sciences de l'environnement de Paris (IEES)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU]Sciences of the Universe [physics], [SDE.MCG]Environmental Sciences/Global Changes, [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, parasitic diseases, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Total and wet mineral dust deposition has been monitored since 2006 at three Sahelian stations in Senegal, Mali, and Niger, respectively at the weekly and the event time scale. Average annual deposited mass fluxes range from 75 to 183 g m À2 yr À1 , from west to east. Deposition fluxes exhibit a clear seasonal cycle in Mali and Niger. High wet deposition fluxes result from an optimum phasing between dust concentration and precipitation: the maximum occurring at the beginning of the wet season, after the maximum of dust concentration and before the precipitation maximum. The contribution of wet to total deposition varies from 67% in Mali to 8% in Senegal. It is the main factor of variability of the deposition fluxes from year to year and at the seasonal scale in Niger and Mali. Wet deposition fluxes in Mali and Niger are mainly due to the wash out of dust emitted by convective systems. In Senegal, the deposition fluxes are lower and dominated by dry deposition (92% of the annual deposition flux). This is due to the low occurrence of convective systems producing local dust emissions and intense wet deposition. The dry deposition fluxes are primarily driven by the variability of the dust concentration. The dry deposition velocities derived from our measurements are consistent with those estimated by theoretical models. Scavenging ratios computed from the measured wet deposition fluxes, dust concentrations, and precipitation are anticorrelated with precipitation amounts. This suggests that most of the atmospheric dust is scavenged at the very beginning of the precipitation events.

Published
2017

40. How long does precipitation inhibit wind erosion in the Sahel?

Author

Bergametti, G., Rajot, J., Pierre, Caroline, Bouet, C., Marticorena, B., Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), European Community, French Agence Nationale de la Recherche (ANR) [ANR-12-SENV-0007-01, ANR ASTRID 2012], Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), and 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)

Subjects
[SDE.MCG]Environmental Sciences/Global Changes, [SDE]Environmental Sciences
Abstract

International audience; Simultaneous measurements of saltation, wind speed, and rainfall performed in Niger before, during, and after 18 rain events are used to investigate how rain events affect wind erosion in the Sahel. The results show that the inhibition of saltation is rapid but progressive after the beginning of a rain event. The decrease of sand transport during the rain event is better linked to the time elapsed from the beginning of the rain event rather than to the cumulative rainfall. In the Sahel, after a rain event, less than 12 h is necessary to almost fully restore the sand transport potential. Our results suggest that assuming that no sand transport and dust emission occur during the 12 h following the end of a rain event could be a reasonable alternative to existing parameterizations of the influence of soil moisture on the wind erosion threshold, at least for the Sahelian conditions.

Published
2016

41. How long does precipitation inhibit wind erosion in the Sahel ? [+ supporting information]

Author

Bergametti, G., Rajot, Jean-Louis, Pierre, C., Bouet, Christel, and Marticorena, B.

Subjects
FACTEUR CLIMATIQUE, PRECIPITATION, HUMIDITE DU SOL, EROSION EOLIENNE
Abstract

Simultaneous measurements of saltation, wind speed, and rainfall performed in Niger before, during, and after 18 rain events are used to investigate how rain events affect wind erosion in the Sahel. The results show that the inhibition of saltation is rapid but progressive after the beginning of a rain event. The decrease of sand transport during the rain event is better linked to the time elapsed from the beginning of the rain event rather than to the cumulative rainfall. In the Sahel, after a rain event, less than 12 h is necessary to almost fully restore the sand transport potential. Our results suggest that assuming that no sand transport and dust emission occur during the 12 h following the end of a rain event could be a reasonable alternative to existing parameterizations of the influence of soil moisture on the wind erosion threshold, at least for the Sahelian conditions.

Published
2016

42. The Mediterranean region under climate change : a scientific update

Author

Khatteli, H., Ramadan Ali, R., Bergametti, G., Bouet, Christel, Hachicha, M., Hamdi-Aissa, B., Labiadh, M., Montoroi, Jean-Pierre, Podwojewski, Pascal, Rajot, Jean-Louis, Mohaamed Zaghloul, A., Valentin, Christian, Thiébault, S. (ed.), and Moatti, Jean-Paul (ed.)

Subjects
CONSERVATION DU SOL, DESERTIFICATION, SURFACE DU SOL, EROSION EOLIENNE, FACTEUR ANTHROPIQUE, RUISSELLEMENT, PRATIQUE CULTURALE, LABOUR, FACTEUR CLIMATIQUE, IRRIGATION, CHANGEMENT CLIMATIQUE, DEGRADATION DU SOL, EROSION HYDRIQUE, CROUTE, SALINISATION, RESTAURATION
Published
2016

43. The Mediterranean region under climate change : a scientific update

Author

Dulac, F. (coord.), Hamonou, E. (coord.), Afif, C., Alkama, R., Ancona, C., Annesi-Maesano, I., Beekmann, M., Benaïssa, F., Bergametti, G., Boissard, C., Borbon, A., Bouet, Christel, Thiébault, S. (ed.), and Moatti, Jean-Paul (ed.)

Subjects
VILLE, AEROSOL, GAZ A EFFET DE SERRE, ATMOSPHERE, PREVENTION, RELATION, FACTEUR ANTHROPIQUE, EROSION EOLIENNE, POLLUTION, CLIMAT, FACTEUR BIOTIQUE, PRECIPITATION, CHANGEMENT CLIMATIQUE, POLLUTION MARINE, SANTE, CIRCULATION ATMOSPHERIQUE, CHIMIE ATMOSPHERIQUE, DEPOT EOLIEN, GAZ CARBONIQUE, QUALITE DE L'AIR, IMPACT SANITAIRE, PROSPECTIVE
Published
2016

44. Erosion éolienne dans les régions arides et semi-arides africaines : processus physiques, métrologie et techniques de lutte

Author

Abdourhamane Toure, A. (ed.), Bergametti, G. (ed.), Bielders, C. (ed.), Bouet, Christel (ed.), Callot, Y. (ed.), Dupont, S. (ed.), Khatteli, H. (ed.), Labiadh, M.T. (ed.), Marticorena, B. (ed.), Rajot, Jean-Louis (ed.), and Valentin, Christian (ed.)

Subjects
METHODE D'ANALYSE, FERTILITE DU SOL, SURFACE DU SOL, VENT, SOL CULTIVE, AEROSOL, TRAVAIL DU SOL, ENSABLEMENT, ETAT DE SURFACE DU SOL, MODELISATION, EROSION EOLIENNE, PRATIQUE CULTURALE, ERODIBILITE DU SOL, LUTTE ANTIEROSIVE, CHANGEMENT CLIMATIQUE, METHODE DE LUTTE, DEPOT EOLIEN, DEGRADATION DU SOL, MESURE, ANALYSE QUANTITATIVE
Published
2015

45. Comparing drag partition schemes over a herbaceous Sahelian rangeland

Author

Pierre, Caroline, Bergametti, G., Marticoréna, B., Kergoat, L., Mougin, Éric, Hiernaux, Pierre, 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), 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), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), 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 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)-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), 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 -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), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-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), 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 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU]Sciences of the Universe [physics], [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Modeling of dust emissions from the surface remains complex, especially in semiarid regions where vegetation must be accounted for because of its potentially important protective effect. Protection is directly linked to the fraction of the soil surface covered by vegetation, but it is also driven by the interaction of vegetation elements with the wind field. The sensitivity of simulated dust emissions to various drag partition schemes-mainly those proposed by Raupach (1992), Marticorena and Bergametti (1995), and Okin (2008)-is evaluated for a typical Sahelian rangeland, covered by a seasonal grass layer, over a complete vegetation cycle. The application of these schemes requires a fine characterization of the vegetation cover; field measurements from an ecological survey are used to derive the geometric dimensions of the grass patches. Models are run with meteorological forcing from automatic weather stations. As a result, the impacts of soil moisture and grass cover are estimated over April to September. Soil moisture inhibits dust emissions by 27% in mass. The different drag partition schemes exhibit distinctive limitations, mostly due to the properties of the Sahelian grass cover, which is composed of large and low patches of short grass, with a strong seasonal dynamics. However, the drag partition schemes result in remarkably coherent estimations of dust emissions. When soil moisture is taken into account, vegetation reduces the total vertical mass fluxes by 6 to 26% of the emissions of a bare soil, depending on the drag partition scheme.

Published
2014

48. Variability of mineral dust deposition in the western Mediterranean basin and South-East of France

Author

Vincent, J., primary, Laurent, B., additional, Losno, R., additional, Bon Nguyen, E., additional, Roullet, P., additional, Sauvage, S., additional, Chevaillier, S., additional, Coddeville, P., additional, Ouboulmane, N., additional, di Sarra, A. G., additional, Tovar-Sánchez, A., additional, Sferlazzo, D., additional, Massanet, A., additional, Triquet, S., additional, Morales Baquero, R., additional, Fornier, M., additional, Coursier, C., additional, Desboeufs, K., additional, Dulac, F., additional, and Bergametti, G., additional

Published
2015
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50. An update on ChArMEx the Chemistry-Aerosol Mediterranean Experiment) activities and plans for aerosol studies in the Mediterranean region

Author

Dulac, F., Bergametti, G., Beekmann, M., Sciare, J., Colomb, A., Losno, R., Mallet, M., Tanre, D., CODDEVILLE, P., Obeo [Gif-sur-Yvette], none, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-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), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), École des Mines de Douai (Mines Douai EMD), and Institut Mines-Télécom [Paris] (IMT)

Subjects
[INFO]Computer Science [cs], ComputingMilieux_MISCELLANEOUS
Abstract

International audience; abstract simple

Published
2012

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