Temporal variability of mineral dust concentrations over West Africa: analyses of a pluriannual monitoring from the AMMA Sahelian Dust Transect

Marticorena, Béatrice; Chatenet, B.; Rajot, Jean-Louis; Traoré, Salifou; Coulibaly, M.; Diallo, Aboubacry; Koné, I.; Maman, A.; Ndiaye, T.; Zakou, A.

doi:10.5194/acp-10-8899-2010

Cited by 174 publications

(213 citation statements)

References 55 publications

(61 reference statements)

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“…1 in Klaver et al, 2011). We do not necessary regard this as a problem, as the atmospheric dust load, both in short-and large-scale transport, is often due to a variety of sources active at the same time (Glaccum and Prospero, 1980;Reid et al, 2003;Formenti et al, 2003;Schepanski et al, 2007;Laurent et al, 2008;McConnell et al, 2008;Marticorena et al, 2010). Also, this supra-imposition, both in the vertical and in the horizontal, is what is actually seen by spaceborne sensors.…”

Section: Identification Of Source Regionsmentioning

confidence: 97%

“…During summer, the Intertropical Convergence Zone (ITCZ) displaces northward, allowing the surface monsoon flow to intrude into the continent from the south-west towards the continental Sahel. This shift induces a progressive organisation of convection from isolated cells to largescale, quickly propagating systems, which, particularly at the beginning of the monsoon season, often do not precipitate and are efficient in eroding bare soils and producing mineral dust (Marticorena et al, 2010;Abdourhamane Touré et al, 2011). The summertime column dust content over western Africa results, therefore, from the superimposition of local emission from the Sahel and remote transport of dust emitted in the Sahara (Tegen and Fung, 1994;Yoshioka et al, 2005;Marticorena et al, 2010).…”

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

confidence: 99%

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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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Section: Identification Of Source Regionsmentioning

confidence: 97%

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

confidence: 99%

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

et al. 2014

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“…The acquisition of quantitative information on the mineral dust content over the Sahel was the main objective of the deployment of the "Sahelian Dust Transect" (SDT) (Marticorena et al, 2010 . The third station, Cinzana, has been included in the AERONET network in the framework of the AMMA project.…”

Section: The Sahelian Dust Transectmentioning

confidence: 99%

“…As described in Marticorena et al (2010) a selection of the data is applied to retain only the periods during which mineral dust are the main contributor to the measured PM 10 mass. The procedure consists in excluding data from wind sectors that can bring other aerosol to the stations.…”

Section: The Sahelian Dust Transectmentioning

confidence: 99%

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Simulation of the mineral dust content over Western Africa from the event to the annual scale with the CHIMERE-DUST model

et al. 2011

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Abstract.The chemistry and transport model CHIMERE-DUST have been used to simulate the mineral dust cycle over the Sahara in 2006. Surface measurements deployed during the AMMA field campaign allow to test the capability of the model to correctly reproduce the atmospheric dust load and surface concentrations from the daily to the seasonal time-scale. The simulated monthly mean Aerosol Optical Depths (AOD) and surface concentrations are significantly correlated with the measured ones. The simulated daily concentrations and hourly AOD are in the same range of magnitude than the observed ones despite relatively high simulated dust emissions. The level of agreement between the simulations and the observations has been quantified at different time scales using statistical parameters classically used to evaluate air quality models. The capability of the model to reproduce the altitude of the dust transport was tested for two contrasted cases of low and high altitude transport. These results highlight the sensitivity of the simulations to the surface winds used as external forcing and the necessity to further constrain the dust mass budget at the regional scale.

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Characterizing the annual cycle of African dust transport to the Caribbean Basin and South America and its impact on the environment and air quality

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Molinié

et al. 2014

Global Biogeochemical Cycles

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Decades of aerosol measurements on Barbados have yielded a detailed picture of African mineral dust transport to the Caribbean Basin that shows a strong seasonal cycle with a maximum in boreal summer and a minimum in winter. Satellite aerosol products suggest that in spring, there is a comparable transport to northeastern South America. Here we characterize the complete annual cycle of dust transport to the western Atlantic by linking the Barbados record to multiyear records of airborne particulate matter less than 10 μm diameter (PM 10 ) measured in air quality programs at Cayenne (French Guiana) and Guadeloupe. Comparisons of PM 10 at these sites with concurrent dust measurements at Barbados demonstrate that high PM 10 levels are almost entirely due to dust. Cayenne PM 10 peaks in spring in a cycle which is consistent with satellite aerosol optical depth and suggests that the Sahel is the dominant source. The persistent transport of dust during much of the year could impact a wide range of environmental processes over a broad region that extends from the southern United States to the Amazon Basin. Finally, the average 24 h PM 10 concentrations at Cayenne and Guadeloupe frequently exceed the World Health Organization air quality guideline. Thus soil dust PM 10 could be a significant, but generally unrecognized, health factor at western Atlantic sites and also in other relatively remote regions affected by long-range dust from Africa. Because dust emissions and transport are highly sensitive to climate variability, climate change in coming decades could greatly affect a wide range of biogeochemical processes and human health in this region.

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Temporal variability of mineral dust concentrations over West Africa: analyses of a pluriannual monitoring from the AMMA Sahelian Dust Transect

Cited by 174 publications

References 55 publications

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

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

Simulation of the mineral dust content over Western Africa from the event to the annual scale with the CHIMERE-DUST model

Characterizing the annual cycle of African dust transport to the Caribbean Basin and South America and its impact on the environment and air quality

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