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| Titel |
Radiocarbon analysis in an Alpine ice core: record of anthropogenic and biogenic contributions to carbonaceous aerosols in the past (1650-1940) |
| VerfasserIn |
T. M. Jenk, S. Szidat, M. Schwikowski, H. W. Gäggeler, S. Brütsch, L. Wacker, H.-A. Synal, M. Saurer |
| 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 ; 6, no. 12 ; Nr. 6, no. 12 (2006-11-29), S.5381-5390 |
| Datensatznummer |
250004192
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| Publikation (Nr.) |
 copernicus.org/acp-6-5381-2006.pdf |
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| Zusammenfassung |
| Long-term concentration records of carbonaceous particles (CP) are of
increasing interest in climate research due to their not yet completely
understood effects on climate. Nevertheless, only poor data on their
concentrations and sources before the 20th century are available. We
present a first long-term record of organic carbon (OC) and elemental carbon
(EC) concentrations – the two main fractions of CP – along with the
corresponding fraction of modern carbon (fM) derived from radiocarbon
(14C) analysis in ice. This allows a distinction and quantification of
natural (biogenic) and anthropogenic (fossil) sources in the past. CP were
extracted from an ice archive, with resulting carbon quantities in the
microgram range. Analysis of 14C by accelerator mass spectrometry (AMS)
was therefore highly demanding. We analysed 33 samples of 0.4 to 1 kg ice
from a 150.5 m long ice core retrieved at Fiescherhorn glacier in December
2002 (46°33'3.2" N, 08°04'0.4" E; 3900 m a.s.l.). Samples were taken
from bedrock up to the firn/ice transition, covering the time period
1650–1940 and thus the transition from the pre-industrial to the industrial
era. Before ~1850, OC was approaching a purely biogenic origin with a
mean concentration of 24 μg kg−1 and a standard deviation of 7 μg kg−1.
In 1940, OC concentration was about a factor of 3 higher
than this biogenic background, almost half of it originating from
anthropogenic sources, i.e. from combustion of fossil fuels. The biogenic EC
concentration was nearly constant over the examined time period with 6 μg kg−1
and a standard deviation of 1 μg kg−1. In 1940, the
additional anthropogenic input of atmospheric EC was about 50 μg kg−1. |
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