 |
| Titel |
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 |
| VerfasserIn |
W. Ju, S. Wang, G. Yu, Y. Zhou, H. Wang |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 3 ; Nr. 7, no. 3 (2010-03-03), S.845-857 |
| Datensatznummer |
250004579
|
| Publikation (Nr.) |
 copernicus.org/bg-7-845-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| Soil and atmospheric water deficits have significant influences on CO2
and energy exchanges between the atmosphere and terrestrial ecosystems.
Model parameterization significantly affects the ability of a model to
simulate carbon, water, and energy fluxes. In this study, an ensemble Kalman
filter (EnKF) and observations of gross primary productivity (GPP) and
latent heat (LE) fluxes were used to optimize model parameters significantly
affecting the calculation of these fluxes for a subtropical coniferous
plantation in southeastern China. The optimized parameters include the
maximum carboxylation rate (Vcmax), the slope in the modified 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 M were more pronounced than the variations between the two years.
Vcmax and M 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
optimization using EnKF, the variations of GPP, LE and SH explained 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 under different
environmental conditions. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|