Identification of optimal soil hydraulic functions and parameters for predicting soil moisture |
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Authors: | Feifei Pan Robert B. McKane Marc Stieglitz |
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Affiliation: | 1. Department of Geography , University of North Texas , Denton , Texas , 76203 , USA feifei.pan@unt.edu;3. US Environmental Protection Agency, Western Ecology Division , Corvallis , Oregon , 97333 , USA;4. School of Civil and Environmental Engineering , Georgia Institute of Technology , Atlanta , Georgia , 30332 , USA;5. School of Earth and Atmospheric Sciences , Georgia Institute of Technology , Atlanta , Geogia , 30332 , USA |
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Abstract: | Abstract The accuracy of six combined methods formed by three commonly-used soil hydraulic functions and two methods to determine soil hydraulic parameters based on a soil hydraulic parameter look-up table and soil pedotransfer functions was examined for simulating soil moisture. A novel data analysis and modelling approach was used that eliminated the effects of evapotranspiration so that specific sources of error among the six combined methods could be identified and quantified. By comparing simulated and observed soil moisture at six sites of the USDA Soil Climate Analysis Network, we identified the optimal soil hydraulic functions and parameters for predicting soil moisture. Through sensitivity tests, we also showed that adjusting only the soil saturated hydraulic conductivity, Ks , is insufficient for representing important effects of macropores on soil hydraulic conductivity. Our analysis illustrates that, in general, soil hydraulic conductivity is less sensitive to Ks than to the soil pore-size distribution parameter. Editor D. Koutsoyiannis; Associate editor D. Hughes Citation Pan, F., McKane, R.B. and Stieglitz, M., 2012. Identification of optimal soil hydraulic functions and parameters for predicting soil moisture. Hydrological Sciences Journal, 57 (4), 723–737. |
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Keywords: | soil moisture Richards equation soil hydraulic functions soil parameters macropore soil pore size distribution index |
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