Meta-analysis of eddy covariance carbon fluxes data Dario Papale, Markus Reichstein, Riccardo Valentini Marc Aubinet, Christian Bernhofer, Alessandro Cescatti, Alexander Knohl, Tuomas Laurila, Anders Lindroth, Eddy Moors, Kim Pilegaard, Günther Seufert
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Meta-analysis of eddy covariance carbon fluxes data Dario Papale, Markus Reichstein, Riccardo Valentini Marc Aubinet, Christian Bernhofer, Alessandro Cescatti,
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Meta-analysis of eddy covariance carbon fluxes data
Dario Papale, Markus Reichstein, Riccardo Valentini
Marc Aubinet, Christian Bernhofer, Alessandro Cescatti, Alexander Knohl, Tuomas Laurila, Anders Lindroth, Eddy Moors, Kim Pilegaard, Günther Seufert
Are the results robust against errors?(advection, footprint, quality, gapfilling, partitioning…)
Results from 500 Monte-Carlo simulations where randomly plus or minus 200 gC m-2 were added to GPP, TER and NEP
At high [S], Km = insignificant
and Q10 of R = Q10 of Vmax (Arrhenius kinetics)
At low [S] : Km becomes important
Also Km increases with Temp
At low [S]: Q10 of R << Q10 of Vmax
Davidson et al., Global Change Biology, in press Thanks Ivan for the slide!
][
][*max
SK
SVR
m
Decomposition = enzymatic process that follows Michaelis-Menten kinetics (1913)
0
0.5
1
1.5
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2.5
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3.5
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0 0.2 0.4 0.6 0.8 1
Relative soil water content (fraction of FC)
Eff
ec
tiv
e Q
10
0
0.5
1
1.5
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3.5
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0 0.2 0.4 0.6 0.8 1
Relative soil water content (fraction of FC)
Eff
ec
tiv
e Q
10
A: Observed from eddy covariance data B: Modelled with BGC-model
5°C
15°C
25°C
5°C
15°C
25°C
Apparent Q10 depends on soil moisture
Under ‘standard’ conditions (15°C; RSWC=0.6) the emergent Q10 of model and data are similar
Along decreasing/increasing water availability data and model behave completely differently with respect to how Q10 changes.
In opposite direction of what models predict
Valentini et al. 2000
Latuitude - NEE relation
Conclusions
• GPP and TER compensate each other canceling out single climate factor effects
• Water availability plays an important role in GPP and TER not only in the Mediterranean region but also in central Europe
• Ecosystem carbon balance modeling approaches should abandon the convenient climate-NPP analogy and better account for carbon-water cycle interactions and non-climatic factors affecting respiration
• Flux tower data are a unique source of information that play an important role in process understanding and model development