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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2017-720
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
01 Nov 2017
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Chemistry and Physics (ACP).
In situ measurements of desert dust particles above the western Mediterranean Sea with the balloon-borne Light Optical Aerosol Counter/sizer (LOAC) during the ChArMEx campaign of summer 2013
Jean-Baptiste Renard1, François Dulac2, Pierre Durand3, Quentin Bourgeois4, Cyrielle Denjean5, Damien Vignelles1, Benoit Couté1, Matthieu Jeannot1,a, Nicolas Verdier6, and Marc Mallet3,b 1Laboratoire de Physique et Chimie de l’Environnement et de l’Espace (LPC2E), UMR CNRS - Université d’Orléans, 3A avenue de la recherches cientifique, Orléans, France
2Laboratoire des Sciences du Climat et de l’Environnement (LSCE), UMR CEA - CNRS - UVSQ, IPSL, Université Paris - Saclay, CEA Saclay 701, Gif - sur - Yvette, France
3Laboratoire d’Aérologie, Université de Toulouse, CNRS, UT3, Toulouse, France
4Department of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
5Centre National de Recherches Météorologiques (CNRM), UMR Météo - France - CNRS, OMP, Météo-France, Toulouse, France
6Centre National d’Etudes Spat iales (CNES), 18 Avenue Edouard Belin, Toulouse, France
anow at: MeteoModem company, Chemin du Moulin, Ury, France
bnow at: CNRM
Abstract. Mineral dust from arid areas is a major component of the global aerosol and has strong interactions with climate and biogeochemistry. As part of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) to investigate atmospheric chemistry and its impacts in the Mediterranean region, an intensive field campaign was performed from mid-June to early August 2013 in the western basin including in situ balloon-borne aerosol measurements with the Light Optical Aerosol Counter (LOAC). LOAC is a counter/sizer that provides the aerosol concentrations in 19 size classes between 0.2 and 100 μm, and an indication of the nature of the particles based on dual angle scattering measurements. A total of 27 LOAC flights were conducted mainly from Minorca Island (Balearic Islands, Spain) but also from Ile du Levant off Hyères city (SE France) under 17 Light Dilatable Balloons (meteorological sounding balloons) and 10 Boundary Layer Pressurized Balloons (quasi-Lagrangian balloons). The purpose was to document the vertical extent of the plume and the time-evolution of the concentrations at constant altitude (air density) by in situ observations. LOAC measurements are in agreement with ground-based measurements (lidar, photometer), aircraft measurements (counters), and satellite measurements (CALIOP) in case of fair spatial and temporal coincidences. LOAC has often detected 3 modes in the dust particle volume size distributions fitted by lognormal laws at roughly 0.2, 4 and 30 µm in modal diameter. Particles larger than 40 μm were observed, with concentrations up to about 10−4 cm−3. Such large particles were lifted several days before and their persistence after transport over long distances is in conflict with calculations of dust sedimentation. We did not observe any significant evolution of the size distribution during the transport from quasi-Lagrangian flights, even for the longest ones (~ 1 day). Finally, the presence of charged particles is inferred from the LOAC measurements and we speculate that electrical forces might counteract gravitational settling of the coarse particles.

Citation: Renard, J.-B., Dulac, F., Durand, P., Bourgeois, Q., Denjean, C., Vignelles, D., Couté, B., Jeannot, M., Verdier, N., and Mallet, M.: In situ measurements of desert dust particles above the western Mediterranean Sea with the balloon-borne Light Optical Aerosol Counter/sizer (LOAC) during the ChArMEx campaign of summer 2013, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-720, in review, 2017.
Jean-Baptiste Renard et al.
Jean-Baptiste Renard et al.
Jean-Baptiste Renard et al.

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Short summary
A campaign was performed in summer 2013 above the Mediterranean basin, including in situ counting balloon-borne aerosol measurements (LOAC), for the detection of mineral dust. Three modes in the dust particle volume size distributions were detected, at roughly 0.2, 4 and 30 micrometers. Particles larger than 40 micrometers were often observed. They were lifted several days before and their persistence after transport over long distances is in conflict with dust sedimentation calculations.
A campaign was performed in summer 2013 above the Mediterranean basin, including in situ...
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