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| Titel |
A test of an optimal stomatal conductance scheme within the CABLE land surface model |
| VerfasserIn |
M. G. De Kauwe, J. Kala, Y.-S. Lin, A. J. Pitman, B. E. Medlyn, R. A. Duursma, G. Abramowitz, Y.-P. Wang, D. G. Miralles |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 8, no. 2 ; Nr. 8, no. 2 (2015-02-24), S.431-452 |
| Datensatznummer |
250116117
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| Publikation (Nr.) |
 copernicus.org/gmd-8-431-2015.pdf |
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| Zusammenfassung |
| Stomatal conductance (gs) affects the fluxes of carbon, energy
and water between the vegetated land surface and the atmosphere. We test an
implementation of an optimal stomatal conductance model within the Community
Atmosphere Biosphere Land Exchange (CABLE) land surface model (LSM). In
common with many LSMs, CABLE does not differentiate between gs model
parameters in relation to plant functional type (PFT), but instead only in
relation to photosynthetic pathway. We constrained the key model parameter
"g1", which represents plant water use strategy, by PFT, based on a
global synthesis of stomatal behaviour. As proof of concept, we also
demonstrate that the g1 parameter can be estimated using two long-term
average (1960–1990) bioclimatic variables: (i) temperature and (ii) an
indirect estimate of annual plant water availability. The new stomatal
model, in conjunction with PFT parameterisations, resulted in a large
reduction in annual fluxes of transpiration (~ 30%
compared to the standard CABLE simulations) across evergreen needleleaf,
tundra and C4 grass regions. Differences in other regions of the globe were
typically small. Model performance against upscaled data products was not
degraded, but did not noticeably reduce existing model–data biases. We
identified assumptions relating to the coupling of the vegetation to the
atmosphere and the parameterisation of the minimum stomatal conductance as
areas requiring further investigation in both CABLE and potentially other
LSMs. We conclude that optimisation theory can yield a simple and tractable
approach to predicting stomatal conductance in LSMs. |
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