Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

Reeves, C. E.; Formenti, Paola; Afif, Charbel; Ancellet, Gérard; Attié, Jean-Luc; Bechara, J.; Borbon, A.; Cairo, F.; Coe, Hugh; Crumeyrolle, S.; Fierli, F.; Flamant, Cyrille; Gomès, L.; Hamburger, T.; Jambert, Corinne; Law, Kathy S.; Mari, C.; Jones, R. L.; Matsuki, Atsushi; Mead, Mohammed Iqbal; Methven, John; Mills, G.; Minikin, Andreas; Murphy, J. G.; Nielsen, Johannes K.; Oram, D. E.; Parker, Douglas J.; Richter, Andreas; Schläger, Hans; Schwarzenböeck, Alfons; Thouret, V.

doi:10.5194/acp-10-7575-2010

Cited by 100 publications

(130 citation statements)

References 116 publications

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“…For example, over Lagos, Nigeria, ozone-enhanced layers are observed in December-February, when burning occurs regionally, and also in July-August, when biomass burning occurs over southern equatorial Africa (Sauvage et al, , 2007b. Such processes have been further investigated in the frame of AMMA (Reeves et al, 2010;Thouret et al, 2009;Mari et al, 2008). Similarly, over Brazzaville, the seasonal cycle of ozone peaks in July-August but a secondary maximum appears in January-February due to transport of ozone and precursors from fires occurring in the Northern Hemisphere (Sauvage et al, , 2007b.…”

Section: Biomass Burningmentioning

confidence: 99%

“…Export of polluted air masses is observed throughout the Gulf of Guinea up to the coast of West Africa in the Northern Hemisphere. Reeves et al (2010) provide a clear characterisation of the ozone distribution throughout the troposphere over West Africa during the monsoon period. Owing to previous analysis based on MOZAIC data (Sauvage et al, 2007a and the regular ozone soundings over Cotonou over 2 years (Thouret et al, 2009), it has been shown that the biomass burning seasons in both hemispheres impact the tropospheric ozone profiles in both hemispheres as well.…”

Section: Atmosmentioning

confidence: 99%

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Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

et al. 2015

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Abstract. Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

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Section: Biomass Burningmentioning

confidence: 99%

Section: Atmosmentioning

confidence: 99%

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

et al. 2015

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“…To provide the quantitative estimate of the mineralogical composition of mineral dust on a regional scale, we report in this paper the synthesis of data from various aircraft and ground-based field campaigns which took place in western Africa in 2006 and 2007. These are the African Monsoon Multidisciplinary Analysis (AMMA) special observing period 0 (SOP0; Rajot et al, 2008), augmented by the airborne Dust and Biomass-burning Experiment (DABEX; Haywood et al, 2008); special observing periods 1 and 2 (SOP1-2; Reeves et al, 2010); the Dust Outflow and Deposition to the Ocean (DODO; McConnell et al, 2008) and the Geostationary Earth Radiation Budget Intercomparison of Longwave…”

Section: P Formenti Et Al: Mapping the Physico-chemical Properties mentioning

confidence: 99%

“…The aircraft performed 13 research flights in the area between 8 and 18 • N, including three dedicated excursion to the north of Niger, toward the Aïr Mountains and the Ténéré desert, to probe specifically mineral dust which was being transported. In summertime, the observations were conducted onboard the Service des Avions Français Instruments pour la Recherche en Environnement (SAFIRE) ATR-42, which operated 20 research flights in the area between 6 and 20 • N, thus crossing the ITCZ to the north; this was done in order to contrast the Sahara and the Sahelian dust properties in their respective boundary layers (Reeves et al, 2010;Formenti et al, 2011b).…”

Section: Field Campaignsmentioning

confidence: 99%

Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition

et al. 2014

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Abstract. In the last few years, several ground-based and airborne field campaigns have allowed the exploration of the properties and impacts of mineral dust in western Africa, one of the major emission and transport areas worldwide. In this paper, we explore the synthesis of these observations to provide a large-scale quantitative view of the mineralogical composition and its variability according to source region and time after transport.This work reveals that mineral dust in western Africa is a mixture of clays, quartz, iron and titanium oxides, representing at least 92 % of the dust mass. Calcite ranged between 0.3 and 8.4 % of the dust mass, depending on the origin. Our data do not show a systematic dependence of the dust mineralogical composition on origin; this is to be the case as, in most of the instances, the data represent the composition of the atmospheric burden after 1-2 days after emission, when air masses mix and give rise to a more uniform dust load. This has implications for the representation of the mineral dust composition in regional and global circulation models and in satellite retrievals.Iron oxides account for 58 ± 7 % of the mass of elemental Fe and for between 2 and 5 % of the dust mass. Most of them are composed of goethite, representing between 52 and 78 % of the iron oxide mass. We estimate that titanium oxides account for 1-2 % of the dust mass, depending on whether the dust is of Saharan or Sahelian origin.The mineralogical composition is a critical parameter for estimating the radiative and biogeochemical impact of mineral dust. The results regarding dust composition have been used to estimate the optical properties as well as the iron fractional solubility of Saharan and Sahelian dust.Data presented in this paper are provided in numerical form upon email request while they are being turned into a public database, the Dust-Mapped Archived Properties (DUST-MAP), which is an open repository for compositional data from other source regions in Africa and worldwide.

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“…Considering that OMI data integrate the atmospheric column of HCHO, comparison with aircraft observations are of particular interest. The airborne HCHO measurements made during INTEX-B (Intercontinental Chemical Transport Experiment B) (Singh et al, 2009;Fried et al, 2011) Multidisciplinary Analysis) (Reeves et al, 2010;Borbon et al, 2012) . We compute the ratio of the posterior to the prior bias between modeled and observed concentrations.…”

Section: Evaluation With Independent Datamentioning

confidence: 99%

The formaldehyde budget as seen by a global-scale multi-constraint and multi-species inversion system

et al. 2012

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Abstract. For the first time, carbon monoxide (CO) and formaldehyde (HCHO) satellite retrievals are used together with methane (CH 4 ) and methyl choloroform (CH 3 CCl 3 or MCF) surface measurements in an advanced inversion system. The CO and HCHO are respectively from the MO-PITT and OMI instruments. The multi-species and multisatellite dataset inversion is done for the 2005-2010 period. The robustness of our results is evaluated by comparing our posterior-modeled concentrations with several sets of independent measurements of atmospheric mixing ratios. The inversion leads to significant changes from the prior to the posterior, in terms of magnitude and seasonality of the CO and CH 4 surface fluxes and of the HCHO production by nonmethane volatile organic compounds (NMVOC). The latter is significantly decreased, indicating an overestimation of the biogenic NMVOC emissions, such as isoprene, in the GEIA inventory. CO and CH 4 surface emissions are increased by the inversion, from 1037 to 1394 TgCO and from 489 to 529 TgCH 4 on average for the 2005-2010 period. CH 4 emissions present significant interannual variability and a joint CO-CH 4 fluxes analysis reveals that tropical biomass burning probably played a role in the recent increase of atmospheric methane.

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Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

Cited by 100 publications

References 116 publications

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition

The formaldehyde budget as seen by a global-scale multi-constraint and multi-species inversion system

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