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| Titel |
Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models |
| VerfasserIn |
E. Zehe, H. Lee, M. Sivapalan  |
| 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 ; 10, no. 6 ; Nr. 10, no. 6 (2006-12-20), S.981-996 |
| Datensatznummer |
250008297
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| Publikation (Nr.) |
 copernicus.org/hess-10-981-2006.pdf |
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| Zusammenfassung |
| In this study we propose an uspcaling approach to derive
time series of (a) REW scale state variables, and (b) effective REW scale
soil hydraulic functions to test and parameterise models based on the REW
approach. To this end we employed a physically based hydrological model,
that represents the typical patterns and structures in the study catchment,
and has previously been shown to reproduce observed runoff response and
state dynamics well. This landscape- and process-compatible model is used to
simulate numerical drainage and wetting experiments. The effective soil
water retention curve and soil hydraulic conductivity curve are derived
using the spatially averaged saturation and capillary pressure as well as
averaged fluxes. When driven with observed boundary conditions during a one
year simulation the model is used to estimate how the spatial pattern of
soil moisture evolved during this period in the catchment. The time series
of the volume integrated soil moisture is deemed as best estimate for the
average catchment scale soil moisture. The approach is applied to the
extensively monitored Weiherbach catchment in Germany. A sensitivity
analysis showed that catchment scale model structures different from the
landscape- and process compatible one yielded different times series of
average catchment scale soil moisture and where not able to reproduce the
observed rainfall runoff response. Hence, subscale typical heterogeneity
leaves a clear fingerprint in the time series of average catchment scale
saturation. In case of the Weiherbach catchment local scale heterogeneity of
ks could be neglected and a simple representation of the typical hillslope
scale patterns of soil types and macroporosity was sufficient for obtaining
effective REW scale soil hydraulic functions. Both the effective soil
hydraulic functions and time series of catchment scale saturation turned out
to be useful to parameterise and test the CREW model, which is based on the
REW approach and was applied to the Weiherbach catchment in a companion
study Lee et al. (2006, this issue). |
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