Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models

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 ty...

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Main Authors: E. Zehe, H. Lee, M. Sivapalan
Format: Article
Language:English
Published: Copernicus Publications 2006-01-01
Series:Hydrology and Earth System Sciences
Online Access:http://www.hydrol-earth-syst-sci.net/10/981/2006/hess-10-981-2006.pdf
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author E. Zehe
H. Lee
M. Sivapalan
author_facet E. Zehe
H. Lee
M. Sivapalan
author_sort E. Zehe
collection DOAJ
description 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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spelling doaj.art-5aacfd6bfce44e7685bf90ab4f021adb2022-12-22T03:11:02ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382006-01-01106981996Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process modelsE. ZeheH. LeeM. SivapalanIn 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).http://www.hydrol-earth-syst-sci.net/10/981/2006/hess-10-981-2006.pdf
spellingShingle E. Zehe
H. Lee
M. Sivapalan
Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models
Hydrology and Earth System Sciences
title Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models
title_full Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models
title_fullStr Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models
title_full_unstemmed Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models
title_short Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models
title_sort dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso scale process models
url http://www.hydrol-earth-syst-sci.net/10/981/2006/hess-10-981-2006.pdf
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AT hlee dynamicalprocessupscalingforderivingcatchmentscalestatevariablesandconstitutiverelationsformesoscaleprocessmodels
AT msivapalan dynamicalprocessupscalingforderivingcatchmentscalestatevariablesandconstitutiverelationsformesoscaleprocessmodels