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| Titel |
Inter-comparison of four different carbon monoxide measurement techniques and evaluation of the long-term carbon monoxide time series of Jungfraujoch |
| VerfasserIn |
C. Zellweger, C. Hüglin, J. Klausen, M. Steinbacher, M. Vollmer, B. Buchmann |
| 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 ; 9, no. 11 ; Nr. 9, no. 11 (2009-06-02), S.3491-3503 |
| Datensatznummer |
250007348
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| Publikation (Nr.) |
 copernicus.org/acp-9-3491-2009.pdf |
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| Zusammenfassung |
| Despite the importance of carbon monoxide (CO) for the overall oxidative
capacity of the atmosphere, there is still considerable uncertainty in
ambient measurements of CO. To address this issue, an inter-comparison
between four different measurement techniques was made over a period of two
months at the high-alpine site Jungfraujoch (JFJ), Switzerland. The
measurement techniques were Non-dispersive Infrared Absorption (NDIR),
Vacuum UV Resonance Fluorescence (VURF), gas chromatographic separation with
a mercuric oxide reduction detector (GC/HgO), and gas chromatographic
separation followed by reduction on a nickel catalyst and analysis by a
flame ionization detector (GC/FID). The agreement among all techniques was
better than 2% for one-hourly averages, which confirmed the suitability
of the NDIR method for CO measurements even at remote sites. The
inter-comparison added to the validation of the 12-year record (1996–2007)
of continuous CO measurements at JFJ. To date this is one of the longest
time series of continuous CO measurements in the free troposphere over
Central Europe. This data record was further investigated with a focus on
trend analysis. A significant negative trend was observed at JFJ showing a
decrease of 21.4±0.3% over the investigated period, or an average
annual decrease of 1.78%/yr (2.65±0.04 ppb/yr). These results were
compared with emission inventory data reported to the Long-range
Transboundary Air Pollution (LRTAP) Convention. It could be shown that long
range transport significantly influences the CO levels observed at JFJ, with
air masses of non-European origin contributing at least one third of the
observed mole fractions. |
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