Aerosol distribution in the northern Gulf of Guinea: local anthropogenic sources, long-range transport, and the role of coastal shallow circulations
Cyrille Flamant
1
Adrien Deroubaix
2, 1
Patrick Chazette
3
Joel Brito
4
Marco Gaetani
1
Peter Knippertz
5
Andreas Fink
5
Gaëlle de Coëtlogon
1
Laurent Menut
2
Aurélie Colomb
4
Cyrielle Denjean
6
Remi Meynadier
7
Philip Rosenberg
8
Régis Dupuy
4
Pamela Dominutti
4
Jonathan Duplissy
9
Thierry Bourrianne
6
Alfons Schwarzenboeck
4
Michel Ramonet
3
Julien Totems
3
Cyrille Flamant 1
Mail :
Author IdHAL : cyrille-flamant ORCID : https://orcid.org/0000-0002-8309-6495
Adrien Deroubaix 2, 1
Author
Patrick Chazette 3
Mail :
Author
Joel Brito 4
Mail :
Author IdHAL : joel-ferreira-de-brito ORCID : https://orcid.org/0000-0002-4420-9442
Marco Gaetani 1
Mail :
Author
Peter Knippertz 5
Author
Andreas Fink 5
Author
Gaëlle de Coëtlogon 1
Mail :
Author
Laurent Menut 2
Mail :
Author
Aurélie Colomb 4
Author
Cyrielle Denjean 6
Author
Remi Meynadier 7
Mail :
Author IdHAL : remi-meynadier
Philip Rosenberg 8
Author
Régis Dupuy 4
Mail :
Author IdHAL : regis-gil-dupuy ORCID : https://orcid.org/0000-0001-5908-0699
Pamela Dominutti 4
Mail :
Author IdHAL : pamela-dominutti ORCID : https://orcid.org/0000-0002-9876-6383
Jonathan Duplissy 9
Mail :
Author
Thierry Bourrianne 6
Author
Alfons Schwarzenboeck 4
Mail :
Author IdHAL : alfons-schwarzenboeck ORCID : https://orcid.org/0000-0002-8386-5506
Michel Ramonet 3
Mail :
Author IdHAL : michel-ramonet ORCID : https://orcid.org/0000-0003-1157-1186
Julien Totems 3
Mail :
Author
1
TROPO - LATMOS (France)
- LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales (11 boulevard d'Alembert
Quartier des Garennes
78280 - Guyancourt - France)
- UVSQ - Université de Versailles Saint-Quentin-en-Yvelines : UMR8190 (55 avenue de Paris - 78035 Versailles cedex - France)
- INSU - CNRS - Institut national des sciences de l'Univers : UMR8190 (INSU-CNRS 3 rue Michel-Ange, 75794 Paris Cedex 16 - France)
- SU - Sorbonne Université : UMR8190 (21 rue de l’École de médecine - 75006 Paris - France)
- CNRS - Centre National de la Recherche Scientifique : UMR8190 (France)
2
LMD - Laboratoire de Météorologie Dynamique (UMR 8539) (LMD ENS 24 Rue Lhomond 75231 Paris Cedex 05 - France)
- UPMC - Université Pierre et Marie Curie - Paris 6 (4 place Jussieu - 75005 Paris - France)
- INSU - CNRS - Institut national des sciences de l'Univers (INSU-CNRS 3 rue Michel-Ange, 75794 Paris Cedex 16 - France)
- X - École polytechnique (École polytechnique, 91128 Palaiseau Cedex - France)
- ENPC - École des Ponts ParisTech (École des Ponts ParisTech 6-8 avenue Blaise-Pascal Cité Descartes 77455 Champs-sur-Marne Marne-la-Vallée cedex 2 - France)
- CNRS - Centre National de la Recherche Scientifique : UMR8539 (France)
- Département des Géosciences - ENS Paris (24 rue Lhomond, 75005 Paris, France - France)
- ENS Paris - École normale supérieure - Paris (45, Rue d'Ulm - 75230 Paris cedex 05 - France)
3
LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (Bât. 12,
avenue de la Terrasse,
F-91198 GIF-SUR-YVETTE CEDEX
- France)
- Université Paris-Saclay (Espace Technologique, Bat. Discovery - RD 128 - 2e ét., 91190 Saint-Aubin - France)
- CEA - Commissariat à l'énergie atomique et aux énergies alternatives : DRF/LSCE (Centre de Saclay Centre de Grenoble Centre de Cadarache etc - France)
- UVSQ - Université de Versailles Saint-Quentin-en-Yvelines : UMR8212 (55 avenue de Paris - 78035 Versailles cedex - France)
- CNRS - Centre National de la Recherche Scientifique : UMR8212 (France)
4
LaMP - Laboratoire de Météorologie Physique - Clermont Auvergne (bat. Physique 5 - 3ème étg / 24 Av des landais / 63177 Aubière Cedex - France)
- INSU - CNRS - Institut national des sciences de l'Univers (INSU-CNRS 3 rue Michel-Ange, 75794 Paris Cedex 16 - France)
- UCA - Université Clermont Auvergne : UMR6016 (49, bd François-Mitterrand / CS 60032 / 63001 Clermont-Ferrand Cedex 1 - France)
- CNRS - Centre National de la Recherche Scientifique : UMR6016 (France)
5
IMK - Institute for Meteorology and Climate Research (Karlsruhe - Germany)
- KIT - Karlsruhe Institute of Technology (Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen / Campus South, Kaiserstraße 12, 76131 Karlsruhe - Germany)
6
CNRM - Centre national de recherches météorologiques (France)
- Météo France (France)
- CNRS - Centre National de la Recherche Scientifique : UMR3589 (France)
7
SPACE - LATMOS (France)
- LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales (11 boulevard d'Alembert
Quartier des Garennes
78280 - Guyancourt - France)
- UVSQ - Université de Versailles Saint-Quentin-en-Yvelines : UMR8190 (55 avenue de Paris - 78035 Versailles cedex - France)
- INSU - CNRS - Institut national des sciences de l'Univers : UMR8190 (INSU-CNRS 3 rue Michel-Ange, 75794 Paris Cedex 16 - France)
- SU - Sorbonne Université : UMR8190 (21 rue de l’École de médecine - 75006 Paris - France)
- CNRS - Centre National de la Recherche Scientifique : UMR8190 (France)
8
ICAS - Institute for Climate and Atmospheric Science [Leeds] (School of Earth and Environment, Leeds. LS2 9JT - United Kingdom)
- SEE - School of Earth and Environment [Leeds] (Maths/Earth and Environment Building, The University of Leeds, Leeds. LS2 9JT - United Kingdom)
- University of Leeds (Woodhouse Lane, Leeds LS2 9JT - United Kingdom)
9
HIP - Helsinki Institute of Physics (P.O. Box 64, FIN-00014 - Finland)
- University of Helsinki (Yliopistonkatu 4, 00100 Helsinki - Finland)
Abstract : The complex vertical distribution of aerosols over coastal southern West Africa (SWA) is investigated using airborne observations and numerical simulations. Observations were gathered on 2 July 2016 offshore of Ghana and Togo, during the field phase of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa project. This was the only flight conducted over the ocean during which a downward-looking lidar was operational. The aerosol loading in the lower troposphere includes emissions from coastal cities (Accra, Lomé, Cotonou, and Lagos) as well as biomass burning aerosol and dust associated with long-range transport from central Africa and the Sahara, respectively. Our results indicate that the aerosol distribution on this day is impacted by subsidence associated with zonal and meridional regional-scale overturning circulations associated with the land–sea surface temperature contrast and orography over Ghana and Togo, as typically observed on hot, cloud-free summer days such as 2 July 2016. Furthermore, we show that the zonal circulation evidenced on 2 July is a persistent feature over the Gulf of Guinea during July 2016. Numerical tracer release experiments highlight the dominance of aged emissions from Accra on the observed pollution plume loadings over the ocean, in the area of aircraft operation. The contribution of aged emission from Lomé and Cotonou is also evident above the marine boundary layer. Given the general direction of the monsoon flow, the tracer experiments indicate no contribution from Lagos emissions to the atmospheric composition of the area west of Cotonou, where our airborne observations were gathered. The tracer plume does not extend very far south over the ocean (i.e. less than 100km from Accra), mostly because emissions are transported northeastward near the surface over land and westward above the marine atmospheric boundary layer. The latter is possible due to interactions between the monsoon flow, complex terrain, and land–sea breeze systems, which support the vertical mixing of the urban pollution. This work sheds light on the complex – and to date undocumented – mechanisms by which coastal shallow circulations can distribute atmospheric pollutants over the densely populated SWA region.
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Journal articles
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https://hal-insu.archives-ouvertes.fr/insu-01768651
Contributor : Catherine Cardon <>
Submitted on : Tuesday, April 17, 2018 - 1:35:26 PM
Last modification on : Wednesday, March 4, 2020 - 12:10:03 PM
Contributor : Catherine Cardon <>
Submitted on : Tuesday, April 17, 2018 - 1:35:26 PM
Last modification on : Wednesday, March 4, 2020 - 12:10:03 PM
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- HAL Id : insu-01768651, version 1
- DOI : 10.5194/acp-18-12363-2018
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INSU | CNRS | METEO | ENS-PARIS | UVSQ | CEA | CEA-UPSAY | X-LMD | LSCE | PSL | X | ENPC | CEA-DRF | PRES_CLERMONT | LAMP | UNIV-PARIS-SACLAY | PARISTECH | X-DEP-MECA | SORBONNE-UNIVERSITE | LATMOS | LMD | ENPC-LMD | SU-SCIENCES
Citation
Cyrille Flamant, Adrien Deroubaix, Patrick Chazette, Joel Brito, Marco Gaetani, et al.. Aerosol distribution in the northern Gulf of Guinea: local anthropogenic sources, long-range transport, and the role of coastal shallow circulations . Atmospheric Chemistry and Physics, European Geosciences Union, 2018, 18, pp.12363-12389. ⟨10.5194/acp-18-12363-2018⟩. ⟨insu-01768651⟩
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