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| Titel |
Improving simulated Amazon forest biomass and productivity by including spatial variation in biophysical parameters |
| VerfasserIn |
A. D. A. Castanho, M. T. Coe, M. H. Costa, Y. Malhi, D. Galbraith, C. A. Quesada |
| 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 ; 10, no. 4 ; Nr. 10, no. 4 (2013-04-05), S.2255-2272 |
| Datensatznummer |
250018183
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| Publikation (Nr.) |
 copernicus.org/bg-10-2255-2013.pdf |
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| Zusammenfassung |
| Dynamic vegetation models forced with spatially homogeneous biophysical
parameters are capable of producing average productivity and biomass values
for the Amazon basin forest biome that are close to the observed estimates,
but these models are unable to reproduce observed spatial variability. Recent
observational studies have shown substantial regional spatial variability of
above-ground productivity and biomass across the Amazon basin, which is
believed to be primarily driven by a combination of soil physical and
chemical properties. In this study, spatial heterogeneity of vegetation
properties is added to the Integrated Biosphere Simulator (IBIS) land surface model, and the simulated
productivity and biomass of the Amazon basin are compared to observations
from undisturbed forest. The maximum RuBiCo carboxylation capacity
(Vcmax) and the woody biomass residence time (τw) were
found to be the most important properties determining the modeled spatial
variation of above-ground woody net primary productivity and biomass,
respectively. Spatial heterogeneity of these properties may lead to simulated
spatial variability of 1.8 times in the woody net primary productivity
(NPPw) and 2.8 times in the woody above-ground biomass
(AGBw). The coefficient of correlation between the modeled and
observed woody productivity improved from 0.10 with homogeneous parameters to
0.73 with spatially heterogeneous parameters, while the coefficient of
correlation between the simulated and observed woody above-ground biomass
improved from 0.33 to 0.88. The results from our analyses with the IBIS
dynamic vegetation model demonstrated that using single values for key
ecological parameters in the tropical forest biome severely limits simulation
accuracy. Clearer understanding of the biophysical mechanisms that drive the
spatial variability of carbon allocation, τw and Vcmax
is necessary to achieve further improvements to simulation accuracy. |
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