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46 results on '"Chevaillier, S."'

2. Mass absorption cross-section of combustion aerosols: A simulation chamber study

Author

Heuser, J., Claudia Di Biagio, Bergé, A., Cazaunau, M., Chevaillier, S., Noyalet, G., Pangui, E., Marco Zanatta, Paolo Laj, Marioni A, Marioni, A., Massabo, D., Prati, P., Renzi, L., Jerôme Yon, Vecchi, R., Bernardoni, V., Vernocchi, V., Jean-Francois Doussin, 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), Complexe de recherche interprofessionnel en aérothermochimie (CORIA), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Yon, Jérôme

Subjects
[SDE] Environmental Sciences, [SDE]Environmental Sciences
Abstract

International audience

Published
2022

3. Exploring the spectral optical properties of soot aerosols and the impact of ageing: a mechanistic study in the large CESAM simulation chamber

Author

Heuser, J, Di Biagio, C, Berge, A, Cazaunau, M, Chevaillier, S, Formenti, P, Gratien, A, Maille, M, Noyalet, G, Pangui, E, Picquet-Varrault, B, Zanatta, M, Decorse, P, Faccinetto, A, Laj, P, Marinoni, A, Massabo, D, Perruchot, C, Petitprez, D, Prati, P, Renzi, L, Yon, J, Doussin, J, 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), Complexe de recherche interprofessionnel en aérothermochimie (CORIA), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Yon, Jérôme

Subjects
[SDE] Environmental Sciences, [SPI]Engineering Sciences [physics], Aerosol Ageing, [SPI] Engineering Sciences [physics], [SDE]Environmental Sciences, Optical Properties, Atmospheric Simulation Chamber, BC
Abstract

International audience

Published
2022

5. Laboratory Investigation of the Spectral Optical Properties of Black Carbon Aerosols: Impact of Composition, Morphology and Aging

Author

Di Biagio, Claudia, Yon, J., Marinoni, Angela, Cazaunau, Mathieu, Pangui, E, Ausset, Patrick, Chevaillier, S., Decorse, P., Formenti, Paola, Maillé, Michel, Perruchot, C., Triquet, Sylvain, Doussin, Jean-Francois, 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), Complexe de recherche interprofessionnel en aérothermochimie (CORIA), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), 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 de Paris (UP)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU]Sciences of the Universe [physics], [SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic
Abstract

International audience; Black Carbon (BC) aerosols, generated by the incomplete combustion of fuels and biomasses, strongly absorb shortwave (SW) radiation which induces a warming at the Top‒Of‒the‒Atmosphere and adds to the regional and global warming by greenhouse gases. Despite its recognized importance, the estimate of the direct radiative effect by BC remains one of the largest uncertainties in the climate forcing assessment. At present the limiting factor remains our inability in representing the spectral optical properties of BC in models, in particular the complex refractive index (CRI=n‒ik). Currently, little is known on the extent and spectral variability of the CRI and its possible modification as a function of different atmospheric aging processes, and its link to particle composition and morphology. BC aerosols in particular are fractal‒like aggregates formed by quasi‒spherical primary particles extremely difficult to represent in an optical model. This complex structure is also continuously changing during atmospheric aging, because of the particle aggregation or restructuration due to coating formation, which can modify their morphology and their spectral optical properties.The BACON (BlAck Carbon Optical agiNg) project was initiated in 2019 with the aim of investigating the spectral optical properties of BC and their modification as a function of atmospheric aging in link to the chemical and morphological state of the particles. BACON is the first phase of the B2C (Black and Brown Carbon) activity investigating absorbing carbonaceous aerosols via simulation chamber experiments in the large CESAM atmospheric simulation chamber (http://www.cesam.cnrs.fr/) at LISA, Créteil, France. A first BACON measurement campaign on BC aerosols in CESAM occurred in July 2019 and focused on both the BC physical aging to evaluate the particle morphological restructuration in dry conditions, and chemical aging to evaluate the change in BC spectral optical properties due to the formation of inorganic and organic coating on the particles. The inorganic coating was obtained by making BC to react with sulfur dioxide (SO2) at 40% RH in presence of ozone (O3), while the organic coating by interaction with Secondary Organic Aerosols (SOA) produced in the chamber by the reaction between α‒pinene, a natural Volatile Organic Compound (VOC), and with O3 oxidant. The BC aerosols were generated by a commercial burner (the miniCAST JING model 5200) and their lifetime exceeded 24 h in the chamber, a time that is sufficient to undergo an aging comparable to that in the atmosphere. The physico‒chemical properties of the BC aerosols (composition, size distribution, density, morphology) were measured at the same time of their spectral optical properties. In particular, the spectral extinction by BC was measured in CESAM both in situ at different relative humidity levels thanks to a new multipath UV-Vis spectrometer and ex situ by commercial instrumentation (cavity ring down cavities, nephelometer, aethalometer). The analysis of particle morphology by transmission electron microscopy (TEM) is used to initiate shape‒advanced optical calculations to retrieve the complex refractive index of the aerosols.In this study we present first results of the BACON campaign in July 2019 and the perspectives for future chamber experiments.This project/work has received funding from the European Union’s Horizon 2020 research and innovation programme through the EUROCHAMP-2020 Infrastructure Activity under grant agreement No 730997. This work was supported by the French National program LEFE (Les Enveloppes Fluides et l’Environnement).

Published
2020

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

Author

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

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

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

Published
2020
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7. Influence of Atmospheric Stability on the Size Distribution of the Vertical Dust Flux Measured in Eroding Conditions Over a Flat Bare Sandy Field

Author

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

Published
2020
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8. 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
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9. Atmospheric chemistry and aerosols: Achievements and perspectives of laboratory simulations @ CNRS CESAM

Author

French- South African innovation days, Doussin, J.-F., Cazaunau, M, Pangui, E, Chevaillier, S, Nowack, S, Berge, A, Di Biagio, C, Caponi, L, Chaput, Amélie, King, James, Gili, Stefania, Vanderstraeten, Aubry, Mattielli, Nadine, Piketh, S, Formenti, Paola, French- South African innovation days, Doussin, J.-F., Cazaunau, M, Pangui, E, Chevaillier, S, Nowack, S, Berge, A, Di Biagio, C, Caponi, L, Chaput, Amélie, King, James, Gili, Stefania, Vanderstraeten, Aubry, Mattielli, Nadine, Piketh, S, and Formenti, Paola

Abstract

info:eu-repo/semantics/published

Published
2019

10. 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
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13. Overview of the Chemistry-Aerosol Mediterranean Experiment/aerosol direct radiative forcing on the Mediterranean climate (ChArMEx/ADRIMED) summer 2013 campaign

Author

Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. RSLAB - Grup de Recerca en Teledetecció, Mallet, Marc, Dulac, F, Formenti, P, Nabat, Pierre, Sciare, J., Roberts, Gareth E., Pelon, Jacques, Ancellet, Gerard, Tanré, Didier, Parol, F, Dejean, C., Brogniez, G., di Sarra, G, Alados Arboledas, Lucas, Arndt, Dorthe, Auriol, F., Blarel, L., Bourrianne, T., Chazette, P, Chevaillier, S., Claeys, Maxim, D'Anna, B., Derimian, Y., Desboeufs, K., Di Iorio, Tatiana, Doussin, J.F., Durand, Pierre, Feron, A., Franay, E., Gaimoz, C., Goloub, Philppe, Gomez Amo, J.L., Granados Muñoz, María José, Sicard, Michaël, Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. RSLAB - Grup de Recerca en Teledetecció, Mallet, Marc, Dulac, F, Formenti, P, Nabat, Pierre, Sciare, J., Roberts, Gareth E., Pelon, Jacques, Ancellet, Gerard, Tanré, Didier, Parol, F, Dejean, C., Brogniez, G., di Sarra, G, Alados Arboledas, Lucas, Arndt, Dorthe, Auriol, F., Blarel, L., Bourrianne, T., Chazette, P, Chevaillier, S., Claeys, Maxim, D'Anna, B., Derimian, Y., Desboeufs, K., Di Iorio, Tatiana, Doussin, J.F., Durand, Pierre, Feron, A., Franay, E., Gaimoz, C., Goloub, Philppe, Gomez Amo, J.L., Granados Muñoz, María José, and Sicard, Michaël

Abstract

The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental setup also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote-sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modeling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to producing high levels of atmospheric pollutants or intense biomass burning ev, Peer Reviewed, Postprint (published version)

Published
2016

15. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

Author

Mallet, M., primary, Dulac, F., additional, Formenti, P., additional, Nabat, P., additional, Sciare, J., additional, Roberts, G., additional, Pelon, J., additional, Ancellet, G., additional, Tanré, D., additional, Parol, F., additional, Denjean, C., additional, Brogniez, G., additional, di Sarra, A., additional, Alados-Arboledas, L., additional, Arndt, J., additional, Auriol, F., additional, Blarel, L., additional, Bourrianne, T., additional, Chazette, P., additional, Chevaillier, S., additional, Claeys, M., additional, D'Anna, B., additional, Derimian, Y., additional, Desboeufs, K., additional, Di Iorio, T., additional, Doussin, J.-F., additional, Durand, P., additional, Féron, A., additional, Freney, E., additional, Gaimoz, C., additional, Goloub, P., additional, Gómez-Amo, J. L., additional, Granados-Muñoz, M. J., additional, Grand, N., additional, Hamonou, E., additional, Jankowiak, I., additional, Jeannot, M., additional, Léon, J.-F., additional, Maillé, M., additional, Mailler, S., additional, Meloni, D., additional, Menut, L., additional, Momboisse, G., additional, Nicolas, J., additional, Podvin, T., additional, Pont, V., additional, Rea, G., additional, Renard, J.-B., additional, Roblou, L., additional, Schepanski, K., additional, Schwarzenboeck, A., additional, Sellegri, K., additional, Sicard, M., additional, Solmon, F., additional, Somot, S., additional, Torres, B, additional, Totems, J., additional, Triquet, S., additional, Verdier, N., additional, Verwaerde, C., additional, Waquet, F., additional, Wenger, J., additional, and Zapf, P., additional

Published
2016
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16. Emission ratios of anthropogenic volatile organic compounds in northern mid-latitude megacities: Observations versus emission inventories in Los Angeles and Paris

Author

Borbon, Agnès, Gilman, J., Kuster, W., Grand, N., Chevaillier, S., Colomb, A., Dolgorouky, C., Gros, V., Lopez, M., Sarda-Esteve, R., Holloway, J., Stutz, J., Petetin, H., Mckeen, S., Beekmann, M., Warneke, C., Parrish, D., de Gouw, J., 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), 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), Chimie Atmosphérique Expérimentale (CAE), 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), ICOS-RAMCES (ICOS-RAMCES), 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-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Institut national des sciences de l'Univers (INSU - CNRS)-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)

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

International audience

Published
2013
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17. Physico-chemical and optical properties of Sahelian and Saharan mineral dust : in situ measurements during the GERBILS campaign

Author

Klaver, A., Formenti, P., Caquineau, Sandrine, Chevaillier, S., Ausset, P., Calzolai, G., Osborne, S., Johnson, B., Harrisone, M., and Dubovik, O.

Subjects
desert aerosols, West Africa, single scattering albedo, sensitivity calculations, mineralogical composition
Abstract

This paper presents new results on the composition, size and shape of mineral dust particles from African sources which were obtained by analysis of bulk filter samples collected in June 2007 onboard the BAe-146 research aircraft of the Facility for Airborne Atmospheric Measurements (FAAM). The aircraft was operated over Mauritania, Mali and Niger during the Geostationary Earth Radiation Budget Intercomparisons of Longwave and Shortwave radiation (GERBILS) campaign. Dust sampled during the campaign originated from various sources, including locally in the Sahel as a result of large-scale convective activity. Regardless of origin, clays (illite, kaolinite) dominated the total volume (79-90%); the remainder was composed of quartz, calcium-rich minerals (calcite, dolomite, gypsum) and alkali feldspars. Iron oxides, measured using a selective chemical extraction method, accounted for 1-3% of the total dust mass. The dependence of particle number size and shape distribution on the origin of dust seems minor too, although our results might be slightly misleading due to the fact that those kinds of data have been gathered on flights when dust had comparable origins and residence time. Mineral dust is only weakly absorbing in the mid-visible wavelengths (single scattering albedo omega(0) > 0.95 at 550 nm), and omega(0) measured values can be reproduced by measuring the bulk fractions of the major minerals, i.e. clays, quartz, calcite and iron oxides. At this wavelength, knowledge of the nature of clays and iron oxides, or the state of mixing of the minerals, does not induce significant differences in the results. A more precise description of the nature of clays and iron oxides is necessary at lower wavelengths owing to larger differences in their spectral optical properties. In particular, knowledge of the nature of the dominant clay is important for determining light scattering in the backward hemisphere.

Published
2011

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

Author

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

Published
2015
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19. Supplementary material to "Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean"

Author

Denjean, C., primary, Cassola, F., additional, Mazzino, A., additional, Triquet, S., additional, Chevaillier, S., additional, Grand, N., additional, Bourrianne, T., additional, Momboisse, G., additional, Sellegri, K., additional, Schwarzenbock, A., additional, Freney, E., additional, Mallet, M., additional, and Formenti, P., additional

Published
2015
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21. Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

Author

Ryder, C. L., primary, McQuaid, J. B., additional, Flamant, C., additional, Rosenberg, P. D., additional, Washington, R., additional, Brindley, H. E., additional, Highwood, E. J., additional, Marsham, J. H., additional, Parker, D. J., additional, Todd, M. C., additional, Banks, J. R., additional, Brooke, J. K., additional, Engelstaedter, S., additional, Estelles, V., additional, Formenti, P., additional, Garcia-Carreras, L., additional, Kocha, C., additional, Marenco, F., additional, Sodemann, H., additional, Allen, C. J. T., additional, Bourdon, A., additional, Bart, M., additional, Cavazos-Guerra, C., additional, Chevaillier, S., additional, Crosier, J., additional, Darbyshire, E., additional, Dean, A. R., additional, Dorsey, J. R., additional, Kent, J., additional, O'Sullivan, D., additional, Schepanski, K., additional, Szpek, K., additional, Trembath, J., additional, and Woolley, A., additional

Published
2015
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22. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

Author

Mallet, M., primary, Dulac, F., additional, Formenti, P., additional, Nabat, P., additional, Sciare, J., additional, Roberts, G., additional, Pelon, J., additional, Ancellet, G., additional, Tanré, D., additional, Parol, F., additional, di Sarra, A., additional, Alados, L., additional, Arndt, J., additional, Auriol, F., additional, Blarel, L., additional, Bourrianne, T., additional, Brogniez, G., additional, Chazette, P., additional, Chevaillier, S., additional, Claeys, M., additional, D'Anna, B., additional, Denjean, C., additional, Derimian, Y., additional, Desboeufs, K., additional, Di Iorio, T., additional, Doussin, J.-F., additional, Durand, P., additional, Féron, A., additional, Freney, E., additional, Gaimoz, C., additional, Goloub, P., additional, Gómez-Amo, J. L., additional, Granados-Muñoz, M. J., additional, Grand, N., additional, Hamonou, E., additional, Jankowiak, I., additional, Jeannot, M., additional, Léon, J.-F., additional, Maillé, M., additional, Mailler, S., additional, Meloni, D., additional, Menut, L., additional, Momboisse, G., additional, Nicolas, J., additional, Podvin, J., additional, Pont, V., additional, Rea, G., additional, Renard, J.-B., additional, Roblou, L., additional, Schepanski, K., additional, Schwarzenboeck, A., additional, Sellegri, K., additional, Sicard, M., additional, Solmon, F., additional, Somot, S., additional, Torres, B., additional, Totems, J., additional, Triquet, S., additional, Verdier, N., additional, Verwaerde, C., additional, Wenger, J., additional, and Zapf, P., additional

Published
2015
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26. Supplementary material to "Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations"

Author

Ryder, C. L., primary, McQuaid, J. B., additional, Flamant, C., additional, Washington, R., additional, Brindley, H. E., additional, Highwood, E. J., additional, Marsham, J. H., additional, Parker, D. J., additional, Todd, M. C., additional, Banks, J. R., additional, Brooke, J. K., additional, Engelstaedter, S., additional, Estellés, V., additional, Formenti, P., additional, Garcia-Carreras, L., additional, Kocha, C., additional, Marenco, F., additional, Rosenberg, P., additional, Sodemann, H., additional, Allen, C. J. T., additional, Bourdon, A., additional, Bart, M., additional, Cavazos-Guerra, C., additional, Chevaillier, S., additional, Crosier, J., additional, Darbyshire, E., additional, Dean, A. R., additional, Dorsey, J. R., additional, Kent, J., additional, O'Sullivan, D., additional, Schepanski, K., additional, Szpek, K., additional, and Woolley, A., additional

Published
2015
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36. Regional variability of the composition of mineral dust from western Africa: Results from the AMMA SOP0/DABEX and DODO field campaigns

Author

Formenti, P., primary, Rajot, J. L., additional, Desboeufs, K., additional, Caquineau, S., additional, Chevaillier, S., additional, Nava, S., additional, Gaudichet, A., additional, Journet, E., additional, Triquet, S., additional, Alfaro, S., additional, Chiari, M., additional, Haywood, J., additional, Coe, H., additional, and Highwood, E., additional

Published
2008
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37. Variability of mineral dust deposition in the western Mediterranean basin and South-East of France.

Author

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

Abstract

Previous studies have provided some insight into the Saharan dust deposition at a few specific locations from observations over long time periods or intensive field campaigns. However, no assessment of the dust deposition temporal variability in connection with its regional spatial distribution has been achieved so far from network observations over more than one year. To investigate dust deposition dynamics at the regional scale, five automatic deposition collectors named CARAGA ("Collecteur Automatique de Retombées Atmosphériques insolubles à Grande Autonomie" in French) have been deployed in the western Mediterranean region during one to three years depending on the station. The sites include, from South to North, Lampedusa Isl., Mallorca Isl., Corsica Isl., Frioul Isl. and Le Casset (South of French Alps). Deposition measurements are performed on a common weekly period at the 5 sites. The mean Saharan dust deposition fluxes are higher close to the North African coasts and decrease following a South to North gradient, with values from 7.4 gm-2 yr-1 in Lampedusa (35°31' N-12°37' E) to 1 gm-2 yr-1 in Le Casset (44°59' N-6°28' E). The maximum deposition flux recorded is of 3.2 gm-2 wk-1 in Mallorca with only 2 other events showing more than 1 gm-2 wk-1 in Lampedusa, and a maximum of 0.5 gm-2 wk-1 in Corsica. The maximum value of 2.1 gm-2 yr-1 observed in Corsica in 2013 is much lower than existing records in the area over the 3 previous decades (11-14 gm-2 yr-1). From the 537 available samples, ninety eight major Saharan dust deposition events have been identified in the records between 2011 and 2013. Complementary observations provided by both satellite and air mass trajectories are used to identify the dust provenance areas and the transport pathways from the Sahara to the stations. Despite the large size of African dust plumes detected by satellites, more than eighty percent of the major dust deposition events are recorded at only one station, suggesting that the dust provenance, transport, and deposition processes (i.e. wet vs. dry) of dust are different and specific for the different deposition sites in the Mediterranean studied area. The results also show that wet deposition is the main way of deposition for mineral dust in the western Mediterranean basin, but the contribution of dry deposition is far to be negligible, and contributes by 15 to 46% to the major dust deposition events, depending on the sampling site. [ABSTRACT FROM AUTHOR]

Published
2015
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38. Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean.

Author

Denjean, C., Cassola, F., Mazzino, A., Triquet, S., Chevaillier, S., Grand, N., Bourrianne, T., Momboisse, G., Sellegri, K., Schwarzenbock, A., Freney, E., Mallet, M., and Formenti, P.

Abstract

This study presents in situ aircraft measurements of Saharan mineral dust transported over the western Mediterranean basin in June-July 2013 during the ChArMEx/ADRIMED (the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) airborne campaign. Dust events differing in terms of source region (Algeria, Tunisia and Morocco), time of tranport (1-5 days) and height of transport were sampled. Mineral dust were transported above the marine boundary layer, which conversely was dominated by pollution and marine aerosols. The dust vertical structure was extremely variable and characterized by either a single layer or a more complex and stratified structure with layers originating from different source regions. Mixing of mineral dust with pollution particles was observed depending on the height of transport of the dust layers. Dust layers carried higher concentration of pollution particles at intermediate altitude (1-3 km) than at elevated altitude (> 3 km), resulting in scattering Angstrom exponent up to 2.2 within the intermediate altitude. However, the optical properties of the dust plumes remained practically unchanged with respect to values previously measured over source regions, regardless of the altitude. Moderate light absorption of the dust plumes was observed with values of aerosol single scattering albedo at 530nm ranging from 0.90 to 1.00 ± 0.04. Concurrent calculations from the aerosol chemical composition revealed a negligible contribution of pollution particles to the absorption properties of the dust plumes that was due to a low contribution of refractory black carbon in regards to the fraction of dust and sulfate particles. This suggests that, even in the presence of moderate pollution, likely a persistent feature in the Mediterranean, the optical properties of the dust plumes could be assimilated to those of native dust in radiative transfer simulations, modeling studies and satellite retrievals over the Mediterranean. Measurements also showed that the coarse mode of mineral dust was conserved even after 5 days of transport in the Mediterranean, which contrasts with the gravitational depletion of large particles observed during the transport of dust plumes over the Atlantic. Simulations with the WRF mesoscale meteorological model highlighted a strong vertical turbulence within the dust layers that could prevent deposition of large particles during their atmospheric transport. This has important implications for the dust radiative effects due to surface dimming, atmospheric heating and cloud formation. The results presented here add to the observational dataset necessary for evaluating the role of mineral dust on the regional climate and rainfall patterns in the western Mediterranean basin. [ABSTRACT FROM AUTHOR]

Published
2015
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39. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign.

Author

Mallet, M., Dulac, F., Formenti, P., Nabat, P., Sciare, J., Roberts, G., Pelon, J., Ancellet, G., Tanré, D., Parol, F., di Sarra, A., Alados, L., Arndt, J., Auriol, F., Blarel, L., Bourrianne, T., Brogniez, G., Chazette, P., Chevaillier, S., and Claeys, M.

Abstract

The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl. fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Forcing on the Mediterranean Climate (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental setup also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modelling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to produce high level of atmospheric pollutants nor intense biomass burning events in the region. However, numerous mineral dust plumes were observed during the campaign with main sources located in Morocco, Algeria and Tunisia, leading to aerosol optical depth (AOD) values ranging between 0.2 to 0.6 (at 440 nm) over the western and central Mediterranean basins. Associated aerosol extinction values measured on-board the ATR-42 within the dust plume show local maxima reaching up to 150 Mm-1. Non negligible aerosol extinction (about 50 Mm-1) was also been observed within the Marine Boundary Layer (MBL). By combining ATR-42 extinction, absorption and scattering measurements, a complete optical closure has been made revealing excellent agreement with estimated optical properties. Associated calculations of the dust single scattering albedo (SSA) have been conducted, which show a moderate variability (from 0.90 to 1.00 at 530 nm). In parallel, active remote-sensing observations from the surface and onboard the F-20 aircraft suggest a complex vertical structure of particles and distinct aerosol layers with sea-salt and pollution located within the MBL, and mineral dust and/or aged north American smoke particles located above (up to 6-7 km in altitude). Aircraft and balloon-borne observations show particle size distributions characterized by large aerosols (> 10 μm in diameter) within dust plumes. In terms of shortwave (SW) direct forcing, in-situ surface and aircraft observations have been merged and used as inputs in 1-D radiative transfer codes for calculating the direct radiative forcing (DRF). Results show significant surface SW instantaneous forcing (up to -90 Wm-2 at noon). Associated 3-D modeling studies from regional climate (RCM) and chemistry transport (CTM) models indicate a relatively good agreement for simulated AOD compared with measurements/observations from the AERO NET/PHOTONS network and satellite data, especially for long-range dust transport. Calculations of the 3-D SW (clear-sky) surface DRF indicate an average of about -10 to -20 Wm-2 (for the whole period) over the Mediterranean Sea together with maxima (-50 W m-2) over northern Africa. The top of the atmosphere (TOA) DRF is shown to be highly variable within the domain, due to moderate absorbing properties of dust and changes in the surface albedo. Indeed, 3-D simulations indicate negative forcing over the Mediterranean Sea and Europe and positive forcing over northern Africa. [ABSTRACT FROM AUTHOR]

Published
2015
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40. An automatic collector to monitor insoluble atmospheric deposition: an application for mineral dust deposition.

Author

Laurent, B., Losno, R., Chevaillier, S., Vincent, J., Roullet, P., Bon Nguyen, E., Ouboulmane, N., Triquet, S., Fornier, M., Raimbault, P., and Bergametti, G.

Subjects
MASS budget (Geophysics), ATMOSPHERIC deposition, MINERAL dusts, AIR masses, TRAJECTORIES (Mechanics)
Abstract

Deposition is one of the key processes controlling the mass budget of the atmospheric mineral dust concentration. However, dust deposition remains poorly constrained in transport models simulating the atmospheric dust cycle. This is mainly due to the limited number of relevant deposition measurements. This paper aims at presenting an automatic collector (CARAGA), specially developed to sample the total (dry and wet) atmospheric deposition of insoluble dust in remote areas. The autonomy of the CARAGA can range from 25 days to almost 1 year depending on the programed sampling time step (1 day and 2 weeks sampling time steps, respectively). This collector is used to sample atmospheric deposition on Frioul Island which is located in the Gulf of Lions in the Western Mediterranean Basin over which Saharan dust can be transported and deposited. To quantify the mineral dust mass in deposition samples, a weighing and ignition protocol is applied. Two years of continuous deposition measurements performed on a weekly time step sampling on Frioul Island are presented and discussed with in-situ measurements, air mass trajectories and satellite observations of dust. [ABSTRACT FROM AUTHOR]

Published
2015
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42. Chemical properties of rain events during the AMMA campaign: an evidence of dust and biogenic influence in the convective systems.

Author

Desboeufs, K., Journet, E., Rajot, J.-L., Chevaillier, S., Triquet, S., Formenti, P., and Zakou, A.

Abstract

This paper documents the chemical composition of 7 rain events associated with mesoscale convective systems sampled at the supersite of Banizoumbou, Niger, during the first special observation periods (June-July 2006) of the African Monsoon Multidisciplinary Analyses (AMMA) experiment. Time-resolved rain sampling was performed in order to discriminate the local dust scavenged at the beginning of rain event from the aerosol particles incorporated in the cloud at the end of the rain. The total elemental composition is dominated by Al, Si, Fe and Ca, indicating a high influence of dust and limited marine or anthropogenic contribution. After the aerosol wash-out, the elemental concentrations normalized to Al and the microscopic observations of diatoms, a tracer of the Bodélé depression, both indicate that the total elemental composition of rainwater is controlled by dust originating from North-Eastern Saharan sources and probably incorporated in the convective cloud from the Harmattan layer. The low variability of the rain composition over the measurement period indicates a regional and temporal homogeneity of dust composition in the Harmattan layer. In the dissolved phase, the dominant anions are nitrate (NO3- ), sulphate (SO42- ) and chloride (Cl-). However, between June and July we observe an increasing contribution of the organic anions (formate, acetate, oxalate) associated with biogenic emissions to the total ion composition. These results confirm the large influence of biogenic emissions on the rain composition over Sahel during the wet season. The paper concludes on the capacity of mesoscale convective systems to carry simultaneously dust and biogenic compounds originating from different locations and depose them jointly. It also discusses the potential biogeochemical impact of such a phenomenon. [ABSTRACT FROM AUTHOR]

Published
2010
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43. Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

Author

Ryder, C.L., McQuaid, Jim B., Flamant, C., Rosenberg, P.D., Washington, R., Brindley, H.E., Highwood, E.J., Marsham, J.H., Parker, D.J., Todd, M.C., Banks, J.R., Brooke, J.K., Engelstaedter, S., Estelles, V., Formenti, P., Garcia-Carreras, L., Kocha, C., Marenco, F., Sodemann, Harald, Allen, C.J.T., Bourdon, A., Bart, M., Cavazos-Guerra, C., Chevaillier, S., Crosier, J., Darbyshire, E., Dean, A.R., Dorsey, J.R., Kent, J., O’Sullivan, D., Schepanski, K., Szpek, K., Trembath, J., and Woolley, A.

Subjects
13. Climate action
Abstract

The Fennec climate programme aims to improve understanding of the Saharan climate system through a synergy of observations and modelling. We present a description of the Fennec airborne observations during 2011 and 2012 over the remote Sahara (Mauritania and Mali) and the advances in the understanding of mineral dust and boundary layer processes they have provided. Aircraft instrumentation aboard the UK FAAM BAe146 and French SAFIRE (Service des Avions Français Instrumentés pour la Recherche en Environnement) Falcon 20 is described, with specific focus on instrumentation specially developed for and relevant to Saharan meteorology and dust. Flight locations, aims and associated meteorology are described. Examples and applications of aircraft measurements from the Fennec flights are presented, highlighting new scientific results delivered using a synergy of different instruments and aircraft. These include (1) the first airborne measurement of dust particles sizes of up to 300 microns and associated dust fluxes in the Saharan atmospheric boundary layer (SABL), (2) dust uplift from the breakdown of the nocturnal low-level jet before becoming visible in SEVIRI (Spinning Enhanced Visible Infra-Red Imager) satellite imagery, (3) vertical profiles of the unique vertical structure of turbulent fluxes in the SABL, (4) in situ observations of processes in SABL clouds showing dust acting as cloud condensation nuclei (CCN) and ice nuclei (IN) at −15 °C, (5) dual-aircraft observations of the SABL dynamics, thermodynamics and composition in the Saharan heat low region (SHL), (6) airborne observations of a dust storm associated with a cold pool (haboob) issued from deep convection over the Atlas Mountains, (7) the first airborne chemical composition measurements of dust in the SHL region with differing composition, sources (determined using Lagrangian backward trajectory calculations) and absorption properties between 2011 and 2012, (8) coincident ozone and dust surface area measurements suggest coarser particles provide a route for ozone depletion, (9) discrepancies between airborne coarse-mode size distributions and AERONET (AERosol Robotic NETwork) sunphotometer retrievals under light dust loadings. These results provide insights into boundary layer and dust processes in the SHL region – a region of substantial global climatic importance., Atmospheric Chemistry and Physics, 15 (14), ISSN:1680-7375, ISSN:1680-7367

45. Exposure to PM 2.5 modulate the pro-inflammatory and interferon responses against influenza virus infection in a human 3D bronchial epithelium model.

Author

Chivé C, Martίn-Faivre L, Eon-Bertho A, Alwardini C, Degrouard J, Albinet A, Noyalet G, Chevaillier S, Maisonneuve F, Sallenave JM, Devineau S, Michoud V, Garcia-Verdugo I, and Baeza-Squiban A

Subjects
Humans, Interferons, Respiratory Mucosa, Antiviral Agents, Epithelium metabolism, Particulate Matter toxicity, Influenza, Human genetics, Influenza, Human metabolism, Virus Diseases, Orthomyxoviridae
Abstract

Epidemiological studies showed a positive association between exposure to PM 2.5 and the severity of influenza virus infection. However, the mechanisms by which PM 2.5 can disrupt antiviral defence are still unclear. From this perspective, the objective of this study was to evaluate the effects of PM 2.5 on antiviral signalling in the respiratory epithelium using the bronchial Calu-3 cell line grown at the air-liquid interface. Pre-exposure to PM 2.5 before infection with the influenza virus was investigated, as well as a co-exposure. Although a physical interaction between the virus and the particles seems possible, no effect of PM 2.5 on viral replication was observed during co-exposure, although a downregulation of IFN-β release was associated to PM 2.5 exposure. However, pre-exposure slightly increased the viral nucleoprotein production and the pro-inflammatory response. Conversely, the level of the myxovirus resistance protein A (MxA), an interferon-stimulated gene (ISG) induced by IFN-β, was reduced. Therefore, these results suggest that pre-exposure to PM 2.5 could alter the antiviral response of bronchial epithelial cells, increasing their susceptibility to viral infection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Published
2024
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46. Community variability of bacteria in alpine snow (Mont Blanc) containing Saharan dust deposition and their snow colonisation potential.

Author

Chuvochina MS, Marie D, Chevaillier S, Petit JR, Normand P, Alekhina IA, and Bulat SA

Subjects
Air Microbiology, Bacteria genetics, Biodiversity, DNA, Bacterial genetics, Ecosystem, Egypt, France, Molecular Sequence Data, Phylogeny, RNA, Ribosomal, 16S genetics, Snow chemistry, Bacteria classification, Bacteria isolation & purification, Dust analysis, Ice Cover microbiology, Snow microbiology
Abstract

Microorganisms uplifted during dust storms survive long-range transport in the atmosphere and could colonize high-altitude snow. Bacterial communities in alpine snow on a Mont Blanc glacier, associated with four depositions of Saharan dust during the period 2006-2009, were studied using 16S rRNA gene sequencing and flow cytometry. Also, sand from the Tunisian Sahara, Saharan dust collected in Grenoble and Mont Blanc snow containing no Saharan dust (one sample of each) were analyzed. The bacterial community composition varied significantly in snow containing four dust depositions over a 3-year period. Out of 61 phylotypes recovered from dusty snow, only three phylotypes were detected in more than one sample. Overall, 15 phylotypes were recognized as potential snow colonizers. For snow samples, these phylotypes belonged to Actinobacteria, Proteobacteria and Cyanobacteria, while for Saharan sand/dust samples they belonged to Actinobacteria, Bacteroidetes, Deinococcus-Thermus and Proteobacteria. Thus, regardless of the time-scale, Saharan dust events can bring different microbiota with no common species set to alpine glaciers. This seems to be defined more by event peculiarities and aeolian transport conditions than by the bacterial load from the original dust source.

Published
2011
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