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| Titel |
Multiple quality tests for analysing CO2 fluxes in a beech temperate forest |
| VerfasserIn |
B. Longdoz, P. Gross, A. Granier |
| 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 ; 5, no. 3 ; Nr. 5, no. 3 (2008-05-07), S.719-729 |
| Datensatznummer |
250002517
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| Publikation (Nr.) |
 copernicus.org/bg-5-719-2008.pdf |
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| Zusammenfassung |
| Eddy covariance (EC) measurements are widely used to estimate the amount of
carbon sequestrated by terrestrial biomes. The decision to exclude an EC
flux from a database (bad quality records, turbulence regime not adequate,
footprint problem,...) becomes an important step in the CO2 flux
determination procedure. In this paper an innovative combination of existing
assessment tests is used to give a relatively complete evaluation of the net
ecosystem exchange measurements. For the 2005 full-leaf season at the Hesse
site, the percentage of rejected half-hours is relatively high (59.7%)
especially during night-time (68.9%). This result strengthens the
importance of the data gap filling method. The data rejection does not lead
to a real improvement of the accuracy of the relationship between the
CO2 fluxes and the climatic factors especially during the nights. The
spatial heterogeneity of the soil respiration (on a site with relatively
homogenous vegetation pattern) seems large enough to mask an increase of the
goodness of the fit of the ecosystem respiration measurements with a
dependence on soil temperature and water content when the tests are used to
reject EC data. However, the data rejected present some common
characteristics. Their removal lead to an increase in the total amount of
CO2 respired (24%) and photosynthesised (16%) during the 2005
full-leaf season. Consequently the application of our combination of
multiple quality tests is able improve the inter-annual analysis. The
systematic application on the large database like the CarboEurope and
FLUXNET appears to be necessary. |
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