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| Titel |
Field intercomparison of two optical analyzers for CH4 eddy covariance flux measurements |
| VerfasserIn |
B. Tuzson, R. V. Hiller, K. Zeyer, W. Eugster, A. Neftel, C. Ammann, L. Emmenegger |
| 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. 6 ; Nr. 3, no. 6 (2010-11-08), S.1519-1531 |
| Datensatznummer |
250001356
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| Publikation (Nr.) |
 copernicus.org/amt-3-1519-2010.pdf |
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| Zusammenfassung |
| Fast response optical analyzers based on laser absorption spectroscopy are
the preferred tools to measure field-scale mixing ratios and fluxes of a
range of trace gases. Several state-of-the-art instruments have become
commercially available and are gaining in popularity. This paper aims for a
critical field evaluation and intercomparison of two compact, cryogen-free
and fast response instruments: a quantum cascade laser based absorption
spectrometer from Aerodyne Research, Inc., and an off-axis integrated cavity
output spectrometer from Los Gatos Research, Inc. In this paper, both
analyzers are characterized with respect to precision, accuracy, response
time and also their sensitivity to water vapour. The instruments were tested
in a field campaign to assess their behaviour under various meteorological
conditions. The instrument's suitability for eddy covariance flux
measurements was evaluated by applying an artificial flux of CH4 generated
above a managed grassland with otherwise very low methane exchange. This allowed
an independent verification of the flux measurements accuracy, including the
overall eddy covariance setup and data treatment. The retrieved fluxes were
in good agreement with the known artificial emission flux, which is more than
satisfactory, given that the analyzers were attached to separate sonic
anemometers placed on individual eddy towers with different data acquisition
systems but similar data treatment that are specific to the best practice
used by the involved research teams. |
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