 |
| Titel |
Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition |
| VerfasserIn |
P. Formenti, S. Caquineau, K. Desboeufs, A. Klaver, S. Chevaillier, E. Journet, J. L. Rajot |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 19 ; Nr. 14, no. 19 (2014-10-10), S.10663-10686 |
| Datensatznummer |
250119090
|
| Publikation (Nr.) |
 copernicus.org/acp-14-10663-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| 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. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|