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1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. Impact of vegetation and soil moisture seasonal dynamics on dust emissions over the Sahel

Author

Pierre, C., Bergametti, G., Marticoréna, B., Mougin, E., Bouet, C., Schmechtig, C., 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), 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 Paris Cité (UPCité), Biogéochimie et écologie des milieux continentaux (Bioemco), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-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), 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), 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), Laboratoire d'océanographie de Villefranche (LOV), 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 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), 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-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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), and 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, VARIATION ANNUELLE, VARIATION SAISONNIERE, COUVERT VEGETAL, SURFACE DU SOL, [SDU]Sciences of the Universe [physics], HUMIDITE DU SOL, AEROSOL, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, DESERT, MODELISATION, EROSION EOLIENNE
Abstract

International audience; [1] To address the challenging issue of estimating mineral dust emissions from the semi-arid Sahel, a modeling approach is developed by combining two specific models: one dedicated to the simulation of the seasonal herbaceous layer in the Sahel (STEP) and the other to the estimation of dust emissions (MB). The area of interest is the Sahelian belt (12 N-20 N, 20 W-35 E) and the simulations were performed at a 0.25 spatial resolution over a 4-year period (2004-2007). The rainfall forcing is provided by a TRMM (Tropical Rainfall Measuring Mission) satellite-derived product; the other meteorological data are ECMWF products. An empirical parameterization is used to estimate the surface roughness and its temporal dynamics according to the characteristics of the simulated vegetation in terms of surface cover and height. Where no vegetation grows, the surface properties are considered as constant in time and are derived from the POLDER-1 satellite measurements. Simulations are constrained step by step by comparisons with observations. Simulated annual dust fluxes emitted from the whole area range from approximately 100 Mt to 400 Mt depending on the year, in good agreement with previous works dealing with Saharan dust emissions. For the fringe where herbaceous vegetation can affect dust emissions, the annual dust emission fluxes range between 0.5 Mt and 20 Mt depending on the year. Inhibition of dust emissions due to the seasonal dynamics of vegetation and surface soil moisture over this fringe varies between 20% and 35%. Citation: Pierre, C., G. Bergametti, B. Marticorena, E. Mougin, C. Bouet, and C. Schmechtig (2012), Impact of vegetation and soil moisture seasonal dynamics on dust emissions over the Sahel

Published
2012

13. An aerodynamic roughness length map derived from extended martian rock abundance data

Author

Hébrard, Eric, Listowski, Constantino, Coll, P., Marticorena, B., Bergametti, G., Määttänen, Anni, Montmessin, Franck, Forget, François, SSE 2012, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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 de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-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 Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre National d’Études Spatiales (CNES)Institut Pierre-Simon Laplace (IPSL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), IMPEC - LATMOS, 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 École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)

Subjects
[PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Rock abundance, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Surface/atmosphere interactions, Aerodynamic roughness length
Abstract

International audience; Many boundary layer processes simulated within a Mars General Circulation Model (MGCM), including the description of the processes controlling dust rising from the Martian surface, are highly sensitive to the aerodynamic roughness length z0. On the basis of rock-size frequency distributions inferred from different Martian landing sites and Earth analog sites, we have first established that lognormal-modeled rock-size frequency distributions are able to reproduce correctly the observed Martian rock populations. We have validated the hypothesis that the rock abundance ζ of a given area could be estimated at a first order from its thermophysical properties, namely its thermal inertia I and its albedo α. We have demonstrated the possibility of using rock abundance ζ to estimate the roughness density λ on Mars and to retrieve subsequently the aerodynamic roughness length by using semi-empirical relationships based on terrestrial wind-tunnel and field measurements. By combining our methodology with remote sensing measurements of the Thermal Emission Spectrometer aboard Mars Global Surveyor, we have derived a global map of the aeolian aerodynamic roughness length with a 1/8° × 1/8° resolution over the entire Martian surface. Contrary to what is often assumed, the Martian aeolian aerodynamic roughness length is spatially highly heterogeneous. At the fullest resolution, the Martian aerodynamic roughness length varies from 10−3 cm to 2.33 cm. About 84% of the Martian surface seems to be characterized by an aeolian aerodynamic roughness length value lower than 1 cm, the spatially uniform value that most of the MGCMs simulations have assumed recently. Since the aerodynamic roughness length z0 is a key parameter in deriving the erosion threshold wind velocities, we anticipate a significant impact of our findings on the efficiencies for lifting dust in future MGCMs.

Published
2012

14. Estimation of Sahelian Aeolian Dust Emissions Based on Vegetation Modelling

Author

Pierre, C., Mougin, Éric, Marticorena, B., Bergametti, G., 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
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; The amount of dust emitted by wind from semi-arid regions is estimated with a large degree of uncertainty, mainly due to the difficulty in accounting for the effects of the seasonal vegetation. The temporal change of the vegetation has been investigated over the Sahelian belt (12°N to 20°N and 20°W to 35°E) from 2004 to 2007 with a daily time resolution. The seasonal vegetation was simulated using the STEP model (Sahelian Transpiration Evaporation and Productivity model; [1] ; [2] ) at scales of 0.1° and 0.25°. The simulations have been compared to the MODIS Leaf Area Indexes (LAI). The comparisons between the simulated vegetation fields and the MODIS LAI have been performed by examining the field structure, the dynamics of the vegetation growth, and the amount of vegetation. The agreement with satellite LAI is very satisfying during the active growth period, both in terms of structure and amount. The period of vegetation growth appears as very sensitive to the initialization parameters of the STEP model, which therefore have been carefully constrained. Based on these vegetation fields, Sahelian dust emissions are simulated and the influence of the seasonal vegetation is estimated.

Published
2010

15. Intercomparison of SCIAMACHY nitrogen dioxide observations, in situ measurements and air quality modeling results over Western Europe

Author

Blond, N., Boersma, K., Eskes, H., van Der A, R., van Roozendael, M., de Smedt, I., Bergametti, G., Vautard, R., Laboratoire Image, Ville, Environnement [Strasbourg] (LIVE), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Royal Netherlands Meteorological Institute (KNMI), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), 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), 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), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), 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), Université de Strasbourg (UNISTRA), 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), 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 Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Atmospheric Composition Division [De Bilt] (ATCOM), and 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)

Subjects
SCIAMACHY, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU]Sciences of the Universe [physics], Air quality modeling, [SHS.GEO]Humanities and Social Sciences/Geography, NO2
Abstract

International audience; [1] The Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) satellite spectrometer provides detailed information on the nitrogen dioxide (NO 2) content in the planetary boundary layer. NO 2 tropospheric column retrievals of SCIAMACHY and its predecessor Global Ozone Monitoring Experiment are characterized by errors of the order of 40%. We present here a new SCIAMACHY tropospheric retrieval data set for the year 2003. The cloud free satellite observations are compared to surface measurements and simulations over western Europe performed with the regional air-quality model CHIMERE. The model has a resolution of 50 km similar to the satellite observations. For these comparisons, averaging kernels are applied to the collocated model profiles to remove the dependency of the comparison on a priori NO 2 profile information used in the retrieval. The consistency of both SCIAMACHY and CHIMERE outputs over sites where surface measurements are available allows us to be confident in evaluation of the model over large areas not covered by surface observations. CHIMERE underestimates surface NO 2 concentrations for urban and suburban stations which we mainly attribute to the low representativeness of point observations. No such bias is found for rural locations. The yearly average SCIAMACHY and CHIMERE spatial NO 2 distributions show a high degree of quantitative agreement over rural and urban sites: a bias of 5% (relative to the retrievals) and a correlation coefficient of 0.87 (n = 2003). On a seasonal basis, biases are smaller than 20% and correlation coefficients are larger than 0.75. Spatial correlations between both the model and satellite columns and the European Monitoring and Evaluation Program (EMEP) emission inventory are high in summer (r = 0.74, n = 1779) and low in winter (r = 0.48, n = 1078), related to seasonal changes in lifetime and transport. On the other hand, CHIMERE and SCIAMACHY columns are mutually consistent in summer (r = 0.82) and in winter (r = 0.79). This shows that CHIMERE simulates the transport and chemical processes with a reasonable accuracy. The NO 2 columns show a high daily variability. The daily NO 2 pollution plumes observed by SCIAMACHY are often well described by CHIMERE both in extent and in location. This result demonstrates the capabilities of a satellite instrument such as SCIAMACHY to monitor the NO 2 concentrations over large areas on a daily basis. It provides evidence that present and future satellite missions, in combination with CTM and surface data, will contribute to improve quantitative air quality analyses at a continental scale. Citation: Blond, N., K. F. Boersma, H. J. Eskes, R. J. van der A, M. Van Roozendael, I. De Smedt, G. Bergametti, and R. Vautard (2007), Intercomparison of SCIAMACHY nitrogen dioxide observations, in situ measurements and air quality modeling results over Western Europe

Published
2007

16. The geostationary tropospheric pollution explorer (GeoTROPE) mission: objectives, requirements and mission concept

Author

Burrows, J.P, Bovensmann, H., Bergametti, G., Flaud, J.M, Orphal, J., No€ El, S, Monks, P.S, Corlett, G.K, Goede, A.P, von Clarmann, T, Steck, T, Fischer, H, Friedl-Vallon, F, Noël, S., Institute of Environmental Physics [Bremen] (IUP), University of Bremen, 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), Institute for Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Laboratoire Lasers, Plasmas et Procédés photoniques (LP3), Aix Marseille Université (AMU)-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), Institut für Meteorologie und Klimaforschung (IMK), Karlsruher Institut für Technologie (KIT), and Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)

Subjects
Pollution, Atmospheric chemistry, 010504 meteorology & atmospheric sciences, Meteorology, media_common.quotation_subject, Cloud cover, Aerospace Engineering, Natural and anthropogenic pollution, 01 natural sciences, Troposphere, Atmosphere, 0103 physical sciences, Atmospheric science, Temporal scales, 010303 astronomy & astrophysics, Air quality index, Tropospheric composition, 0105 earth and related environmental sciences, media_common, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Astronomy and Astrophysics, Remote sensing, Geophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Geostationary orbit, General Earth and Planetary Sciences, Environmental science, Scale (map)
Abstract

International audience; One of the major challenges facing atmospheric sciences is to assess, understand and quantify the impact of natural and an-thropogenic pollution on the quality of life on Earth on a local, regional and continental scale. It has become apparent that pollution originating from local/regional events can have serious effects on the composition of the lower atmosphere on a continental scale. However, to understand the effects of regional pollution on a continental scale there is a requirement to transcend traditional atmospheric spatial and temporal scales and attempt to monitor the entire atmosphere at the same time. In the troposphere the variability of chemical processes, of source strength and the dynamics induce important short term, i.e., sub-hourly, variations and significant horizontal and vertical variability of constituents and geophysical parameters relevant to a range of contemporary issues such as air quality. To study tropospheric composition, it is therefore required to link diurnal with seasonal and annual timescales, as well as local and regional with continental spatial scales, by performing sub-hourly measurements at appropriate horizontal and vertical resolution. Tropospheric observations from low-Earth orbit (LEO) platforms have already demonstrated the potential of detecting constituents relevant for air quality but they are limited, for example by the daily revisit time and local cloud cover statistics. The net result of this is that the troposphere is currently significantly under sampled. Measurements from Geostationary Orbit (GEO) offer the only practical approach to the observation of diurnal variation from space with the pertinent horizontal resolution. The Geostationary Tropospheric Pollution Explorer (GeoTROPE) is an attempt to determine tropospheric constituents with high temporal and spatial resolution. The paper will summarise the needs for geostationary observations of tropospheric composition and will give the mission objectives and the requirements.

Published
2004

17. Modeling the atmospheric distribution of mineral aerosol: comparison with ground measurements and satellite observations for yearly and synoptic time scales over the north Atlantic

Author

Guelle, Walter, Balkanski, Y., Schulz, Michael, Marticorena, Beatrice, Bergametti, G., Moulin, Cyril, Arimoto, R., Perry, K.D., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), 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), CEMRC/New Mexico State University, and 1400 University Drive

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU]Sciences of the Universe [physics], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2000

18. Factors controlling threshold friction velocities in semi-arid areas of the United States

Author

Marticorena, Beatrice, Bergametti, G., Gillette, Dale, Belnap, Jayne, 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), NOAA Air Resources Laboratory (ARL), National Oceanic and Atmospheric Administration (NOAA), 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, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]
Abstract

International audience; A physical model was developed to explain threshold friction velocities u*t for particles of the size 60–120 μm lying on a rough surface in loose soils for semiarid and arid parts of the United States. The model corrected for the effect of momentum absorption by the nonerodible roughness. For loose or disturbed soils the most important parameter that controls u*t is the aerodynamic roughness height z0. For physical crusts damaged by wind the size of erodible crust pieces is important along with the roughness. The presence of cyanobacteriallichen soil crusts roughens the surface, and the biological fibrous growth aggregates soil particles. Only undisturbed sandy soils and disturbed soils of all types would be expected to be erodible in normal wind storms. Therefore disturbance of soils by both cattle and humans is very important in predicting wind erosion as confirmed by our measurements.

Published
1997

19. Origins of African dust transported over the northeastern tropical Atlantic: Meteorological and trajectography analysis, geochemical characteristics

Author

Chiapello, Isabelle, Bergametti, G., Chatenet, Bernadette, Bousquet, Philippe, Dulac, François, santos soares, emmanuel, 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), 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), Laboratoire de Bioingénierie et NanoSciences (LBN), Université de Montpellier (UM)-Université Montpellier 1 (UM1), 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 des Faibles Radioactivités, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Servico Nacional de Meteorologia i Geofisic, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille, 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 Montpellier 1 (UM1)-Université de Montpellier (UM), and Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

International audience; On the basis of 3 years of daily measurements of mineral dust concentrations at Sal Island (Cape Verde), this study focuses on the origin of the dust transported over the northeastern tropical Atlantic during the dusty season (October to April). Using backward trajectories, we have identified three different sectors of origin of the transported dust, covering the Sahara (north/west and central/south) and the Sahel regions. Time variations of the dust transport from these different areas can be explained by the seasonal shift of the subtropical high‐pressure center. A geochemical approach highlights that the calcium amount and the Si/Al ratio of the transported dust differ according to these source regions, in relation to their respective soil compositions.

Published
1997

20. INFLUENCE DE LA TENEUR EN PARTICULES DE L'ATMOSPHERE SUR L'EFFICACITE DE PIEGEAGE DES AEROSOLS

Author

Bergametti, G., Vie Le Sage, R, Grubis, B, Dulieu, B, Elichegaray, C, 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), Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7), and 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

International audience; The association of a sampling system such as a cascad impactor and an analytical technique like X‐ray spectrometry allows, in theory, to separate the aerosol in six granulometric classes corresponding to different origines, residence times and toxicity. However, the variation of acmospheric load, in particular for the submicronic particules, may induce, in time, a modification of impaction characteristics and it ends up with mixing of aerosols wich belong to different classes.

Published
1982

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

Author

Christel Bouet, Mohamed Labiadh, Gilles Bergametti, Badie Attoui, Benoit Laurent, Beatrice Marticorena, Jean Rajot, Houcine Khatteli, 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 des Régions Arides (IRA), 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 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), 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.), Valentin, Christian (ed.), 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
SURFACE DU SOL, VENT, SOL CULTIVE, [SDE.MCG]Environmental Sciences/Global Changes, HUMIDITE DU SOL, ETUDE REGIONALE, AEROSOL, TRAVAIL DU SOL, METEOROLOGIE, ETAT DE SURFACE DU SOL, MODELISATION, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, EROSION EOLIENNE, PRATIQUE CULTURALE, [SDE.MCG] Environmental Sciences/Global Changes, ERODIBILITE DU SOL, DEGRADATION DU SOL, ANALYSE QUANTITATIVE, ANALYSE MATHEMATIQUE, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, UTILISATION DU SOL, ComputingMilieux_MISCELLANEOUS
Abstract

Les régions arides du sud de la Tunisie sont des zones naturellement très sensibles à l'érosion éolienne. Non seulement les précipitations dans ces régions sont faibles (inférieures à 200 mm), mais les sols sont fins, sableux et peu profonds, c'est-à-dire facilement érodables par le vent. L'utilisation de nouvelles techniques agricoles à la place des techniques traditionnelles a conduit à une augmentation de l'érosion éolienne dans ces régions. Par exemple, l'augmentation croissante de l'utilisation de la déchaumeuse à disques a eu d'importantes conséquences sur la dégradation des champs en modifiant la structure des sols et les caractéristiques de leur surface. Le présent travail de modélisation est centré sur la quantification de la déflation éolienne à l'échelle du sud tunisien en vue de déterminer en particulier les zones les plus sensibles à ce phénomène pour des objectifs de diagnostic et de stratégie de lutte efficace contre l'érosion éolienne. Les flux d'érosion éolienne sur le sud de la Tunisie ont été simulés pour l'année 2008 à une résolution de 10 km x 10 km en prenant en compte le type d'usage des sols et les pratiques agricoles associées à l'aide du modèle d'érosion éolienne Dust Production Model (DPM, Marticorena et Bergametti [1995] ; Alfaro et al. [1998]). Afin de prendre en compte les différents types d'outils agricoles utilisés sur le domaine étudié, les paramétrisations du seuil et du flux d'érosion éolienne en fonction des caractéristiques des billons de labour (hauteur et espacement) développées par Kardous et al. [2005a ; b] ont été intégrées au DPM. [...]

Published
2015

22. Vers une quantification de l'érosion éolienne des sols labourés dans le sud tunisien

Author

Mohamed Labiadh, Gilles Bergametti, Christel Bouet, Houcine Khatteli, Mounir Abichou, Institut des Régions Arides (IRA), 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 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), Institut des oliviers, 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 d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) ), bergametti, gilles, 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.), Valentin, Christian (ed.), and 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)

Subjects
[SDE] Environmental Sciences, physical process, [SDE.MCG]Environmental Sciences/Global Changes, soil losses, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, érosion éolienne, [SDE.MCG] Environmental Sciences/Global Changes, sud tunisien, processus physique, [SDE]Environmental Sciences, southern Tunisia, wind erosion, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, pertes en sol brutes
Abstract

International audience; La Tunisie, par sa situation géographique, possède un climat diversifié dominé par l'aridité. Globalement, les trois quarts du pays sont menacés par la désertification, les milieux arides de la Tunisie méridionale et centrale et les milieux semi-arides de la Dorsale et d'une partie du Tell septentrional étant plus particulièrement concernés. Ces terres du sud tunisien, au-dessous de l'isohyète 200 mm an-1 , connaissent de sérieux problèmes d'ensablement qui résultent de la sévérité des conditions climatiques et d'un mode d'exploitation inapproprié des ressources naturelles qui est à l'origine de la vulnérabilité du couvert végétal naturel et des sols. Par ailleurs, le labour des sols sensibles à l'érosion éolienne pour des pratiques de céréaliculture et de culture des oliviers est à l'origine de l'amplification de ce phénomène au cours des dernières décennies. Le but de cette étude est d'utiliser les résultats de trois expériences menées à l'échelle de la parcelle dans le sud tunisien, pour quantifier l'érosion éolienne sur des surfaces agricoles, pour tester la capacité d'un outil de modélisation numérique à reproduire les flux en masse mesurés. L'approche adoptée repose sur des paramétrisations reliant le flux horizontal de particules aux dimensions géométriques des sillons. La validation expérimentale de cette approche est basée sur différentes expériences de terrain menées sur des parcelles travaillées avec différents outils de labour. Les résultats montrent un bon accord entre simulations et observations. Mots-clefs : érosion éolienne, processus physique, pertes en sol brutes, sud tunisien

Published
2015

23. ORIGIN OF PARTICULATE POTASSIUM IN Mt ETNA EMISSIONS BEFORE AND DURING THE 1983 ERUPTION

Author

J.L. Colin, J. P. Quisefit, J. Pinart, Gilles Bergametti, Dario Tedesco, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Paris (UP)-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)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre des Faibles Radioactivités, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Osservatorio Vesuviano, Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Napoli (INGV), Istituto Nazionale di Geofisica e Vulcanologia-Istituto Nazionale di Geofisica e Vulcanologia, 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico-Chimie de l'Atmosphère (LPCA), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale, Quisefit, J. P., Bergametti, G, Tedesco, Dario, and Pinart, J. COLIN J. L.

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Potassium, Mineralogy, chemistry.chemical_element, Particulates, 010502 geochemistry & geophysics, 01 natural sciences, Plume, Aerosol, Geophysics, Etna volcano, chemistry, Volcano, Impact crater, 13. Climate action, Geochemistry and Petrology, Environmental chemistry, Erosion, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Particulate potassium compounds in Mt Etna emissions can be associated with two mechanisms of formation: (a) at magmatic vents, potassium compounds generally result from condensation of primary gaseous compounds and (b) in fumarolic areas wall-rock erosion is the main source. Bulk filtration samples were collected on Mt Etna Volcano between the 16 and 23 March 1983, and on the March 28 1983 additional samples were collected above active vents. Analyses of particulates containing Al, Si, S, Cl, K and Zn suggest a simple model of origin for these elements during the 1983 pre-eruptive period. The results also show that, about ten days before the eruption, volatile potassium compounds in the plume of the summit crater decreased abruptly. From these data, we suggest that monitoring of potassium bearing particulates could be used to determine the character of the volcanic emissions.

Published
1988

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