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| Titel |
The importance of micrometeorological variations for photosynthesis and transpiration in a boreal coniferous forest |
| VerfasserIn |
G. Schurgers, F. Lagergren, M. Mölder, A. Lindroth |
| 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 ; 12, no. 1 ; Nr. 12, no. 1 (2015-01-14), S.237-256 |
| Datensatznummer |
250117769
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| Publikation (Nr.) |
 copernicus.org/bg-12-237-2015.pdf |
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| Zusammenfassung |
Plant canopies affect the canopy micrometeorology, and thereby alter
canopy exchange processes. For the simulation of these exchange
processes on a regional or global scale, large-scale vegetation
models often assume homogeneous environmental conditions within the
canopy. In this study, we address the importance of vertical
variations in light, temperature, CO2 concentration and
humidity within the canopy for fluxes of photosynthesis and transpiration of
a boreal coniferous forest in central Sweden. A leaf-level
photosynthesis-stomatal conductance model was used for aggregating
these processes to canopy level while applying the within-canopy
distributions of these driving variables.
The simulation model showed good agreement with eddy
covariance-derived gross primary production (GPP) estimates on daily and annual timescales, and
showed a reasonable agreement between transpiration and observed
H2O fluxes, where discrepancies are largely attributable to
a lack of forest floor evaporation in the model. Simulations in
which vertical heterogeneity was artificially suppressed revealed
that the vertical distribution of light is the driver of vertical
heterogeneity. Despite large differences between above-canopy and
within-canopy humidity, and despite large gradients in CO2
concentration during early morning hours after nights with stable
conditions, neither humidity nor CO2 played an important
role for vertical heterogeneity of photosynthesis and transpiration. |
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