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| Titel |
Aircraft-borne aerosol chemical composition measurements in the lower to middle troposphere over southern West Africa: Biomass burning, urban outflow plumes, and long-range transport. |
| VerfasserIn |
Anneke Batenburg, Christiane Schulz, Johannes Schneider, Daniel Sauer, Hans Schlager, Stephan Borrmann |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250141795
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| Publikation (Nr.) |
 EGU/EGU2017-5339.pdf |
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| Zusammenfassung |
| During the DACCIWA field campaign in June and July 2016, aircraft-borne in-situ
aerosol chemical composition measurements were performed over southern West
Africa (SWA). This presentation will focus on the submicron particle measurements
done with a Compact Time-of-Flight Aerosol Mass Spectrometer (C-ToF-AMS) on
board of the DLR Falcon aircraft during twelve research flights from Lomé, Togo,
covering the altitude range from the boundary layer (BL) to the middle troposphere (12
km).
A preliminary analysis of the results shows typical baseline total non-refractory
aerosol mass loadings of 1.5 to 2.8 μg m−3 in the BL, and 0.4 to 1.1 μg m−3above.
Up to half of the baseline aerosol mass in the BL appears to consist of sulphate,
compared to only 10 to 35 % above the BL; organic matter dominates in the middle
troposphere.
During several flights, the DLR Falcon crossed a pronounced and seemingly widespread
aerosol layer at 2—4.5 km altitude, partly in or slightly above the BL. The AMS data indicate
that about half of the non-refractory aerosol mass in the middle of this layer consisted of
organic matter. We consider it likely that these aerosol particles were produced by biomass
burning in Central Africa.
Emissions from cities and industrial areas were also intercepted, as well as enhancements
in some species at higher altitudes. Trajectory analysis suggests that an increase of the
organics to more than 2.5 μg m−3 observed at 8 km during one flight came from
the Arabian Peninsula. Several ammonium peaks during the same flight at higher
altitudes were traced back to the Asian Summer Monsoon Anticyclone (ASMA). |
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