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| Titel |
Continuous measurements of methane mixing ratios from ice cores |
| VerfasserIn |
C. Stowasser, C. Buizert, V. Gkinis, J. Chappellaz, S. Schüpbach, M. Bigler, X. Faïn, P. Sperlich, M. Baumgartner, A. Schilt, T. Blunier |
| 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 ; 5, no. 5 ; Nr. 5, no. 5 (2012-05-09), S.999-1013 |
| Datensatznummer |
250002861
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| Publikation (Nr.) |
 copernicus.org/amt-5-999-2012.pdf |
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| Zusammenfassung |
| This work presents a new, field-deployable technique for continuous,
high-resolution measurements of methane mixing ratios from ice cores. The
technique is based on a continuous flow analysis system, where ice core
samples cut along the long axis of an ice core are melted continuously. The
past atmospheric air contained in the ice is separated from the melt water
stream via a system for continuous gas extraction. The extracted gas is
dehumidified and then analyzed by a Wavelength Scanned-Cavity Ring Down
Spectrometer for methane mixing ratios. We assess the performance of the new
measurement technique in terms of precision (±0.8 ppbv, 1σ),
accuracy (±8 ppbv), temporal (ca. 100 s), and spatial resolution
(ca. 5 cm). Using a firn air transport model, we compare the resolution of
the measurement technique to the resolution of the atmospheric methane signal
as preserved in ice cores in Greenland. We conclude that our measurement
technique can resolve all climatically relevant variations as preserved in
the ice down to an ice depth of at least 1980 m (66 000 yr before present)
in the North Greenland Eemian Ice Drilling ice core. Furthermore, we describe
the modifications, which are necessary to make a commercially available
spectrometer suitable for continuous methane mixing ratio measurements from
ice cores. |
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