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Titel |
Field intercomparison of four methane gas analyzers suitable for eddy covariance flux measurements |
VerfasserIn |
O. Peltola, I. Mammarella, S. Haapanala, G. Burba, T. Vesala |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 10, no. 6 ; Nr. 10, no. 6 (2013-06-11), S.3749-3765 |
Datensatznummer |
250018282
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Publikation (Nr.) |
copernicus.org/bg-10-3749-2013.pdf |
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Zusammenfassung |
Performances of four methane gas analyzers suitable for eddy covariance
measurements are assessed. The assessment and comparison was performed by
analyzing eddy covariance data obtained during summer 2010 (1 April to
26 October) at a pristine fen, Siikaneva, Southern Finland. High methane
fluxes with pronounced seasonality have been measured at this fen. The four
participating methane gas analyzers are commercially available closed-path
units TGA-100A (Campbell Scientific Inc., USA), RMT-200 (Los Gatos Research,
USA), G1301-f (Picarro Inc., USA) and an early prototype open-path unit
Prototype-7700 (LI-COR Biosciences, USA).
The RMT-200 functioned most reliably throughout the measurement campaign,
during low and high flux periods. Methane fluxes from RMT-200 and G1301-f had
the smallest random errors and the fluxes agree remarkably well throughout
the measurement campaign. Cospectra and power spectra calculated from RMT-200
and G1301-f data agree well with corresponding temperature spectra during a
high flux period. None of the gas analyzers showed statistically significant
diurnal variation for methane flux. Prototype-7700 functioned only for a
short period of time, over one month, in the beginning of the measurement
campaign during low flux period, and thus, its overall accuracy and
season-long performance were not assessed. The open-path gas analyzer is a
practical choice for measurement sites in remote locations due to its low
power demand, whereas for G1301-f methane measurements interference from
water vapor is straightforward to correct since the instrument measures both
gases simultaneously. In any case, if only the performance in this
intercomparison is considered, RMT-200 performed the best and is the
recommended choice if a new fast response methane gas analyzer is needed. |
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