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| Titel |
Quantifying black carbon from biomass burning by means of levoglucosan – a one-year time series at the Arctic observatory Zeppelin |
| VerfasserIn |
K. E. Yttri, C. Lund Myhre, S. Eckhardt, M. Fiebig, C. Dye, D. Hirdman, J. Ström, Z. Klimont, A. Stohl |
| 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 ; 14, no. 12 ; Nr. 14, no. 12 (2014-06-27), S.6427-6442 |
| Datensatznummer |
250118842
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| Publikation (Nr.) |
 copernicus.org/acp-14-6427-2014.pdf |
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| Zusammenfassung |
Levoglucosan, a highly specific tracer of particulate matter from biomass
burning, has been used to study the influence of residential wood burning,
agricultural waste burning and Boreal forest fire emissions on the Arctic
atmosphere black carbon (BC) concentration. A one-year time series from
March 2008 to March 2009 of levoglucosan has been established at the Zeppelin
observatory in the European Arctic. Elevated concentrations of levoglucosan
in winter (mean: 1.02 ng m−3) compared to summer (mean:
0.13 ng m−3) were observed, resembling the seasonal variation seen for e.g.
sulfate and BC. The mean concentration in the winter period was 2–3
orders of magnitude lower than typical values reported for European
urban areas in winter, and 1–2 orders of magnitude lower than
European rural background concentrations. Episodes of elevated levoglucosan
concentration lasting from 1 to 6 days were more frequent in winter than in
summer and peak values were higher, exceeding 10 ng m−3 at the most.
Concentrations of elemental carbon from biomass burning (ECbb) were
obtained by combining measured concentrations of levoglucosan and emission
ratios of levoglucosan and EC for wildfires/agricultural fires and for
residential wood burning. Neglecting chemical degradation by OH provides
minimum levoglucosan concentrations, corresponding to a mean ECbb
concentration of 3.7 ± 1.2 ng m−3 in winter (October–April) and
0.8 ± 0.3 ng m−3 in summer (May–September), or
8.8 ± 4.5% of the measured equivalent black carbon (EBC) concentration in
winter and 6.1 ± 3.4% in summer. When accounting for chemical
degradation of levoglucosan by OH, an upper estimate of 31–45% of EBC
could be attributed to ECbb* (ECbb adjusted for chemical
degradation) in winter, whereas no reliable (<100%) upper
estimate could be provided for summer for the degradation rates applied.
Hence, fossil fuel sources appear to dominate the European Arctic BC
concentrations in winter, whereas the very wide range obtained for summer
does not allow us to conclude upon this for the warm season.
Calculations using the Lagrangian particle dispersion model FLEXPART show
that the seasonal variation of the modeled ECbb (ECbb,m)
concentration compared relatively well with observationally derived
ECbb from agricultural fires/wildfires during summer, and residential wood
burning in winter. The model overestimates by a factor of 2.2 in winter and
4.4 in summer when compared to the observationally derived mean ECbb
concentration, which provides the minimum estimate, whereas it
underestimates by a factor of 2.3–3.3 in winter and a factor of 4.5 in
summer when compared to ECbb*, which provides the upper
estimate. There are indications of too-low emissions of residential wood
burning in northern Russia, a region of great importance with respect to
observed concentrations of BC in the European Arctic. |
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