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| Titel |
Assessing seasonality of biochemical CO2 exchange model parameters from micrometeorological flux observations at boreal coniferous forest |
| VerfasserIn |
T. Thum, T. Aalto, T. Laurila, M. Aurela, A. Lindroth, 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 ; 5, no. 6 ; Nr. 5, no. 6 (2008-12-03), S.1625-1639 |
| Datensatznummer |
250002928
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| Publikation (Nr.) |
 copernicus.org/bg-5-1625-2008.pdf |
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| Zusammenfassung |
| The seasonality of the NEE of the northern boreal coniferous forests was
investigated by means of inversion modelling using eddy covariance data.
Eddy covariance data was used to optimize the biochemical model parameters.
Our study sites consisted of three Scots pine (l. Pinus sylvestris) forests and one Norway
spruce (l. Picea abies) forest that were located in Finland and Sweden. We obtained
temperature and seasonal dependence for the biochemical model parameters:
the maximum rate of carboxylation (Vc(max)) and the maximum rate of
electron transport (Jmax). Both of the parameters were optimized without
assumptions about their mutual magnitude. The values obtained for the
biochemical model parameters were similar at all the sites during summer
time. To describe seasonality, different temperature fits were made for the
spring, summer and autumn periods. During summer, average Jmax across the
sites was 54.0 μmol m−2 s−1 (variance 31.2 μmol m−2 s−1)
and Vc(max) was 12.0 μmol m−2 s−1 (variance 6.6 μmol m−2 s−1)
at 17°C. The sensitivity of the model to LAI and atmospheric soil water stress was also studied. The impact of
seasonality on annual GPP was 17% when only summertime parameterization
was used throughout the year compared to seasonally changing
parameterizations. |
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