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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 18, 445-465, 2018
https://doi.org/10.5194/acp-18-445-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
16 Jan 2018
Interactions of atmospheric gases and aerosols with the monsoon dynamics over the Sudano-Guinean region during AMMA
Adrien Deroubaix1,2, Cyrille Flamant2, Laurent Menut1, Guillaume Siour3, Sylvain Mailler1, Solène Turquety1, Régis Briant1, Dmitry Khvorostyanov1, and Suzanne Crumeyrolle4 1LMD/IPSL, École Polytechnique, Université Paris Saclay, ENS, IPSL Research University, Sorbonne Universités, UPMC Univ Paris 06, CNRS, Palaiseau, France
2LATMOS/IPSL, UPMC, Sorbonne Universités, CNRS & UVSQ, Paris, France
3LISA/IPSL, Universités Paris Est Créteil & Paris Diderot, Créteil, France
4LOA, Université Lille 1 Sciences et Technologies, Villeneuve d'Ascq, France
Abstract. Carbon monoxide, CO, and fine atmospheric particulate matter, PM2.5, are analyzed over the Guinean Gulf coastal region using the WRF-CHIMERE modeling system and observations during the beginning of the monsoon 2006 (from May to July), corresponding to the Africa Multidisciplinary Monsoon Analysis (AMMA) campaign period.

Along the Guinean Gulf coast, the contribution of long-range pollution transport to CO or PM2.5 concentrations is important. The contribution of desert dust PM2.5 concentration decreases from  ∼ 38 % in May to  ∼ 5 % in July. The contribution of biomass burning PM2.5 concentration from Central Africa increases from  ∼ 10 % in May to  ∼ 52 % in July. The anthropogenic contribution is  ∼ 30 % for CO and  ∼ 10 % for PM2.5 during the whole period.

When focusing only on anthropogenic pollution, frequent northward transport events from the coast to the Sahel are associated with periods of low wind and no precipitation. In June, anthropogenic PM2.5 and CO concentrations are higher than in May or July over the Guinean coastal region. Air mass dynamics concentrate pollutants emitted in the Sahel due to a meridional atmospheric cell. Moreover, a part of the pollution emitted remotely at the coast is transported and accumulated over the Sahel.

Focusing the analysis on the period 8–15 June, anthropogenic pollutants emitted along the coastline are exported toward the north especially at the beginning of the night (18:00 to 00:00 UTC) with the establishment of the nocturnal low level jet. Plumes originating from different cities are mixed for some hours at the coast, leading to high pollution concentration, because of specific disturbed meteorological conditions.


Citation: Deroubaix, A., Flamant, C., Menut, L., Siour, G., Mailler, S., Turquety, S., Briant, R., Khvorostyanov, D., and Crumeyrolle, S.: Interactions of atmospheric gases and aerosols with the monsoon dynamics over the Sudano-Guinean region during AMMA, Atmos. Chem. Phys., 18, 445-465, https://doi.org/10.5194/acp-18-445-2018, 2018.
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Short summary
CO and PM2.5 are analyzed over the Guinean Gulf coastal region during the beginning of the 2006 West African monsoon. A biomass burning plume from Central Africa is observed since June at the Guinean coast. In June, the modeled anthropogenic PM2.5 concentrations are higher than in May or July. An important part of the pollution emitted along the coastline is transported to the north at night within the surface layer and within the nocturnal low-level jet.
CO and PM2.5 are analyzed over the Guinean Gulf coastal region during the beginning of the 2006...
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