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| Titel |
Uncertainty in parameterisation and model structure affect simulation results in coupled ecohydrological models |
| VerfasserIn |
S. Arnold, S. Attinger, K. Frank, A. Hildebrandt |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 10 ; Nr. 13, no. 10 (2009-10-06), S.1789-1807 |
| Datensatznummer |
250012018
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| Publikation (Nr.) |
 copernicus.org/hess-13-1789-2009.pdf |
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| Zusammenfassung |
| In this paper we develop and apply a conceptual ecohydrological model to
investigate the effects of model structure and parameter uncertainty on the
simulation of vegetation structure and hydrological dynamics. The model is
applied for a typical water limited riparian ecosystem along an ephemeral
river: the middle section of the Kuiseb River in Namibia. We modelled this
system by coupling an ecological model with a conceptual hydrological model.
The hydrological model is storage based with stochastical forcing from the
flood. The ecosystem is modelled with a population model, and represents
three dominating riparian plant populations. In appreciation of uncertainty
about population dynamics, we applied three model versions with increasing
complexity. Population parameters were found by Latin hypercube sampling of
the parameter space and with the constraint that three species should
coexist as observed. Two of the three models were able to reproduce the
observed coexistence. However, both models relied on different coexistence
mechanisms, and reacted differently to change of long term memory in the
flood forcing. The coexistence requirement strongly constrained the
parameter space for both successful models. Only very few parameter sets
(0.5% of 150 000 samples) allowed for coexistence in a representative
number of repeated simulations (at least 10 out of 100) and the success of
the coexistence mechanism was controlled by the combination of population
parameters. The ensemble statistics of average values of hydrologic
variables like transpiration and depth to ground water were similar for both
models, suggesting that they were mainly controlled by the applied
hydrological model. The ensemble statistics of the fluctuations of depth to
groundwater and transpiration, however, differed significantly, suggesting
that they were controlled by the applied ecological model and coexistence
mechanisms. Our study emphasizes that uncertainty about ecosystem structure
and intra-specific interactions influence the prediction of the hydrosystem. |
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