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Modeling the impact of drought on canopy carbon and water fluxes for a subtropical evergreen coniferous plantation in southern China through parameter optimization using an ensemble Kalman filter
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ju, Weimin Wang, Shaoqiang Yu, Guo Rong Zhou, Yanlian Wang, Housheng |
| Copyright Year | 2010 |
| Abstract | Soil and atmospheric water deficits have signif- icant influences on CO 2 and energy exchanges between the atmosphere and terrestrial ecosystems. Model parameteriza- tion significantly affects the ability of a model to simulate carbon, water, and energy fluxes. In this study, an ensem- ble Kalman filter (EnKF) and observations of gross primary productivity (GPP) and latent heat (LE) fluxes were used to optimize model parameters significantly affecting the calcu- lation of these fluxes for a subtropical coniferous plantation in southeastern China. The optimized parameters include the maximum carboxylation rate (Vcmax), the slope in the mod- ified Ball-Berry model ( M) and the coefficient determining the sensitivity of stomatal conductance to atmospheric water vapor deficit ( D0). Optimized Vcmax and M showed larger variations than D0. Seasonal variations of Vcmax and Mwere more pronounced than the variations between the two years. Vcmax andM were associated with soil water content (SWC). During dry periods, SWC at the 20 cm depth explained 61% and 64% of variations of Vcmax and M, respectively. EnKF parameter optimization improved the simulations of GPP, LE and SH, mainly during dry periods. After parameter opti- mization using EnKF, the variations of GPP, LE and SH ex- plained by the model increased by 1% to 4% at half-hourly steps and by 3% to 5% at daily time steps. Further efforts are needed to differentiate the real causes of parameter variations and improve the ability of models to describe the change of stomatal conductance with net photosynthesis rate and the sensitivity of photosynthesis capacity to soil water stress un- der different environmental conditions. |
| Starting Page | 845 |
| Ending Page | 857 |
| Page Count | 13 |
| File Format | PDF HTM / HTML |
| DOI | 10.5194/bg-7-845-2010 |
| Volume Number | 7 |
| Alternate Webpage(s) | https://www.biogeosciences.net/7/845/2010/bg-7-845-2010.pdf |
| Alternate Webpage(s) | https://doi.org/10.5194/bg-7-845-2010 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
