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| Titel |
Simulating carbon and water cycles of larch forests in East Asia by the BIOME-BGC model with AsiaFlux data |
| VerfasserIn |
M. Ueyama, K. Ichii, R. Hirata, K. Takagi, J. Asanuma, T. Machimura, Y. Nakai, T. Ohta, N. Saigusa, Y. Takahashi, T. Hirano |
| 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 ; 7, no. 3 ; Nr. 7, no. 3 (2010-03-10), S.959-977 |
| Datensatznummer |
250004587
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| Publikation (Nr.) |
 copernicus.org/bg-7-959-2010.pdf |
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| Zusammenfassung |
Larch forests are widely distributed across many cool-temperate and boreal
regions, and they are expected to play an important role in global carbon
and water cycles. Model parameterizations for larch forests still contain
large uncertainties owing to a lack of validation. In this study, a
process-based terrestrial biosphere model, BIOME-BGC, was tested for larch
forests at six AsiaFlux sites and used to identify important environmental
factors that affect the carbon and water cycles at both temporal and spatial
scales.
The model simulation performed with the default deciduous conifer parameters
produced results that had large differences from the observed net ecosystem
exchange (NEE), gross primary productivity (GPP), ecosystem respiration
(RE), and evapotranspiration (ET). Therefore, we adjusted several model
parameters in order to reproduce the observed rates of carbon and water
cycle processes. This model calibration, performed using the AsiaFlux data,
substantially improved the model performance. The simulated annual GPP, RE,
NEE, and ET from the calibrated model were highly consistent with observed
values.
The observed and simulated GPP and RE across the six sites were positively
correlated with the annual mean air temperature and annual total
precipitation. On the other hand, the simulated carbon budget was partly
explained by the stand disturbance history in addition to the climate. The
sensitivity study indicated that spring warming enhanced the carbon sink,
whereas summer warming decreased it across the larch forests. The summer
radiation was the most important factor that controlled the carbon fluxes in
the temperate site, but the VPD and water conditions were the limiting
factors in the boreal sites. One model parameter, the allocation ratio of
carbon between belowground and aboveground, was site-specific, and it was
negatively correlated with the annual climate of annual mean air temperature
and total precipitation. Although this study substantially improved the
model performance, the uncertainties that remained in terms of the
sensitivity to water conditions should be examined in ongoing and long-term
observations. |
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