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| Titel |
Long-term in situ observations of biomass burning aerosol at a high altitude station in Venezuela – sources, impacts and interannual variability |
| VerfasserIn |
T. Hamburger, M. Matisāns, P. Tunved, J. Ström, S. Calderon, P. Hoffmann, G. Hochschild, J. Gross, T. Schmeissner, A. Wiedensohler, R. Krejci |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 19 ; Nr. 13, no. 19 (2013-10-07), S.9837-9853 |
| Datensatznummer |
250085734
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| Publikation (Nr.) |
 copernicus.org/acp-13-9837-2013.pdf |
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| Zusammenfassung |
| First long-term observations of South American biomass burning
aerosol within the tropical lower free troposphere are
presented. The observations were conducted between 2007 and 2009 at
a high altitude station (4765 m a.s.l.) on the Pico Espejo,
Venezuela. Sub-micron particle volume, number concentrations of
primary particles and particle absorption were observed. Orographic
lifting and shallow convection leads to a distinct diurnal cycle at
the station. It enables measurements within the lower free
troposphere during night-time and observations of boundary layer air
masses during daytime and at their transitional regions. The
seasonal cycle is defined by a wet rainy season and a dry biomass
burning season. The particle load of biomass burning aerosol is
dominated by fires in the Venezuelan savannah. Increases of aerosol
concentrations could not be linked to long-range transport of
biomass burning plumes from the Amazon basin or Africa due to
effective wet scavenging of particles. Highest particle
concentrations were observed within boundary layer air masses during
the dry season. Ambient sub-micron particle volume reached
1.4±1.3 μm3 cm−3, refractory particle
number concentrations (at 300 °C) 510±420 cm−3 and the
absorption coefficient 0.91±1.2 Mm−1. The
respective concentrations were lowest within the lower free
troposphere during the wet season and averaged at 0.19±0.25 μm3 cm−3, 150±94 cm−3 and
0.15±0.26 Mm−1. A decrease of particle
concentrations during the dry seasons from 2007–2009 could be
connected to a decrease in fire activity in the wider region of
Venezuela using MODIS satellite observations. The variability of
biomass burning is most likely linked to the El Niño–Southern
Oscillation (ENSO). Low biomass burning activity in the Venezuelan
savannah was observed to follow La Niña conditions, high biomass
burning activity followed El Niño conditions. |
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