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| Titel |
Analysis of non-methane hydrocarbons in air samples collected aboard the CARIBIC passenger aircraft |
| VerfasserIn |
A. K. Baker, F. Slemr, C. A. M. Brenninkmeijer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 3, no. 1 ; Nr. 3, no. 1 (2010-02-26), S.311-321 |
| Datensatznummer |
250000831
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| Publikation (Nr.) |
 copernicus.org/amt-3-311-2010.pdf |
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| Zusammenfassung |
The CARIBIC project (Civil Aircraft for the Regular Investigation of the
atmosphere Based on an Instrument Container) is a long-term monitoring
program making regular atmospheric measurements from an instrument container
installed monthly aboard a passenger aircraft. Typical cruising altitudes of
the aircraft allow for the study of the free troposphere and the
extra-tropical upper troposphere as well as the lowermost stratosphere.
CARIBIC measurements include a number of real time analyses as well as the
collection of aerosol and whole air samples. These whole air samples are
analyzed post-flight for a suite of trace gases, which includes non-methane
hydrocarbons (NMHC).
The NMHC measurement system and its analytical performance are described
here. Precision was found to vary slightly by compound, and is less than
2% for the C2–C6 alkanes and ethyne, and between 1% and
6% for C7–C8 alkanes and aromatic compounds. Preliminary
results from participation in a Global Atmospheric Watch (WMO) VOC audit
indicate accuracies within the precision of the system. Limits of detection
are 1 pptv for most compounds, and up to 3 pptv for some aromatics. These
are sufficiently low to measure mixing ratios typically observed in the
upper troposphere and lowermost stratosphere for the longer-lived NMHC,
however, in air samples from these regions many of the compounds with
shorter lifetimes (<5 days) were frequently below the detection limit.
Observed NMHC concentrations span several orders of magnitude, dependent on
atmospheric region and air mass history, with concentrations typically
decreasing with shorter chemical lifetimes. |
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