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Titel |
The importance of Asia as a source of black carbon to the European Arctic during springtime 2013 |
VerfasserIn |
D. Liu, B. Quennehen, E. Darbyshire, J. D. Allan, P. I. Williams, J. W. Taylor, S. J.-B. Bauguitte, M. J. Flynn, D. Lowe, M. W. Gallagher, K. N. Bower, T. W. Choularton, H. Coe |
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 ; 15, no. 20 ; Nr. 15, no. 20 (2015-10-20), S.11537-11555 |
Datensatznummer |
250120104
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Publikation (Nr.) |
copernicus.org/acp-15-11537-2015.pdf |
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Zusammenfassung |
Black carbon aerosol (BC) deposited to the Arctic sea ice or present in the
free troposphere can significantly affect the Earth's radiation budget at
high latitudes yet the BC burden in these regions and the regional source
contributions are poorly constrained. Aircraft measurements of aerosol
composition in the European Arctic were conducted during the Aerosol–Cloud
Coupling And Climate Interactions in the Arctic (ACCACIA) campaign in March 2013. Pollutant plumes were encountered throughout the lower to upper Arctic
troposphere featuring enhancements in CO and aerosol mass loadings, which
were chemically speciated into BC and non-refractory sulphate and organic
matter. FLEXPART-WRF simulations have been performed to evaluate the likely
contribution to the pollutants from regional ground sources. By combining
up-to-date anthropogenic and open fire biomass burning (OBB) inventories, we
have been able to compare the contributions made to the observed pollution
layers from the sources of eastern/northern Asia (AS), Europe (EU) and North
America (NA). Over 90 % of the contribution to the BC was shown to arise
from non-OBB anthropogenic sources.
AS sources were found to be the major contributor to the BC burden,
increasing background BC loadings by a factor of 3–5 to 100.8 ± 48.4 ng sm−3 (in standard air m3 at 273.15 K and 1013.25 mbar) and
55.8 ± 22.4 ng sm−3 in the middle and upper troposphere
respectively. AS plumes close to the tropopause (about 7.5–8 km) were also
observed, with BC concentrations ranging from 55 to 73 ng sm−3, which
will potentially have a significant radiative impact. EU sources influenced
the middle troposphere with a BC mean concentration of 70.8 ± 39.1 ng sm−3 but made a minor contribution to the upper troposphere due to the
relatively high latitude of the source region. The contribution of NA was
shown to be much lower at all altitudes with BC mean concentration of 20 ng sm−3. The BC transported to the Arctic is mixed with a non-BC volume
fraction representing between 90–95 % of the mass, and has a relatively
uniform core size distribution with mass median diameter 190–210 nm and
geometric standard deviation σg = 1.55–1.65 and this varied
little across all source regions. It is estimated that 60–95 % of BC is
scavenged between emission and receptor based on BC / ΔCO comparisons
between source inventories and measurement.
We show that during the springtime of 2013, the anthropogenic pollution
particularly from sources in Asia, contributed significantly to BC across
the European Arctic free troposphere. In contrast to previous studies, the
contribution from open wildfires was minimal. Given that Asian pollution is
likely to continue to rise over the coming years, it is likely that the
radiative forcing in the Arctic will also continue to increase. |
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