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| Titel |
Effects of climate variability and functional changes on the interannual variation of the carbon balance in a temperate deciduous forest |
| VerfasserIn |
J. Wu, L. Linden, G. Lasslop, N. Carvalhais, K. Pilegaard, C. Beier, A. Ibrom |
| 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 ; 9, no. 1 ; Nr. 9, no. 1 (2012-01-03), S.13-28 |
| Datensatznummer |
250006647
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| Publikation (Nr.) |
 copernicus.org/bg-9-13-2012.pdf |
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| Zusammenfassung |
| The net ecosystem exchange of CO2 (NEE) between the atmosphere and a
temperate beech forest showed a significant interannual variation (IAV) and
a decadal trend of increasing carbon uptake (Pilegaard et al., 2011). The objectives of this study were to evaluate to what extent
and at which temporal scale, direct climatic variability and changes in
ecosystem functional properties regulated the IAV of the carbon balance at
this site. Correlation analysis showed that the sensitivity of carbon fluxes
to climatic variability was significantly higher at shorter than at longer
time scales and changed seasonally. Ecosystem response anomalies implied
that changes in the distribution of climate anomalies during the vegetation
period will have stronger impacts on future ecosystem carbon balances than
changes in average climate.
We improved a published modelling approach which distinguishes the direct
climatic effects from changes in ecosystem functioning (Richardson et al.,
2007) by employing the semi empirical model published by
Lasslop et al. (2010b). Fitting the model in short moving
windows enabled large flexibility to adjust the parameters to the seasonal
course of the ecosystem functional state. At the annual time scale as much
as 80% of the IAV in NEE was attributed to the variation in
photosynthesis and respiration related model parameters. Our results suggest
that the observed decadal NEE trend at the investigated site was dominated
by changes in ecosystem functioning. In general this study showed the
importance of understanding the mechanisms of ecosystem functional change.
Incorporating ecosystem functional change into process based models will
reduce the uncertainties in long-term predictions of ecosystem carbon
balances in global climate change projections. |
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