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| Titel |
Net ecosystem CO2 exchange measurements by the closed chamber method and the eddy covariance technique and their dependence on atmospheric conditions |
| VerfasserIn |
M. Riederer, A. Serafimovich, T. Foken |
| 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 ; 7, no. 4 ; Nr. 7, no. 4 (2014-04-25), S.1057-1064 |
| Datensatznummer |
250115700
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| Publikation (Nr.) |
 copernicus.org/amt-7-1057-2014.pdf |
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| Zusammenfassung |
| Carbon dioxide flux measurements in ecosystem sciences are mostly conducted
by eddy covariance technique or the closed chamber method. But there is a
lack of detailed comparisons that assess present differences and
uncertainties. To determine underlying processes, a 10-day, side-by-side
measurement of the net ecosystem exchange with both techniques was evaluated
with regard to various atmospheric conditions during the diurnal cycle. It
was found that, depending on the particular atmospheric condition, the
chamber carbon dioxide flux was either (i) equal to the carbon dioxide flux
measured by the reference method eddy covariance, by day with well-developed
atmospheric turbulence; (ii) higher, in the afternoon in times of oasis
effect; (iii) lower, predominantly at night while large coherent structure
fluxes or high wind velocities prevailed; or (iv) showed less variation in
the flux pattern, at night while stable stratification was present. At night
– when respiration forms the net ecosystem exchange – lower chamber carbon
dioxide fluxes were found. In the afternoon – when the ecosystem is still a
net carbon sink – the carbon dioxide fluxes measured by the chamber
prevailed. These two complementary aspects resulted in an overestimation of
the ecosystem sink capacity by the chamber of 40% in this study. |
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