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| Titel |
An empirical model simulating diurnal and seasonal CO2 flux for diverse vegetation types and climate conditions |
| VerfasserIn |
M. Saito, S. Maksyutov, R. Hirata, A. D. Richardson |
| 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 ; 6, no. 4 ; Nr. 6, no. 4 (2009-04-16), S.585-599 |
| Datensatznummer |
250003640
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| Publikation (Nr.) |
 copernicus.org/bg-6-585-2009.pdf |
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| Zusammenfassung |
| We present an empirical model for the estimation of diurnal variability in
net ecosystem CO2 exchange (NEE) in various biomes. The model is based on
the use of a simple saturated function for photosynthetic response of the
canopy, and was constructed using the AmeriFlux network dataset that contains
continuous eddy covariance CO2 flux data obtained at 24 ecosystems sites
from seven biomes. The physiological parameters of maximum CO2 uptake rate
by the canopy and ecosystem respiration have biome-specific responses to
environmental variables. The model uses simplified empirical expression of
seasonal variability in biome-specific physiological parameters based on air
temperature, vapor pressure deficit, and annual precipitation. The model was
validated using measurements of NEE derived from 10 AmeriFlux and four
AsiaFlux ecosystem sites. The predicted NEE had reasonable magnitude and
seasonal variation and gave adequate timing for the beginning and end of the
growing season; the model explained 83–95% and 76–89% of the observed
diurnal variations in NEE for the AmeriFlux and AsiaFlux ecosystem sites used
for validation, respectively. The model however worked less satisfactorily in
two deciduous broadleaf forests, a grassland, a savanna, and a tundra
ecosystem sites where leaf area index changed rapidly. These results suggest
that including additional plant physiological parameters may improve the
model simulation performance in various areas of biomes. |
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