HR: 17:40h
AN: H34E-07 INVITED    [Abstracts]
TI: Soil Moisture Variability and Mean Soil Moisture: A Stochastic Hydraulic Perspective
AU: * Vereecken, H
EM: h.vereecken@fz-juelich.de
AF: Agrosphere (ICG-4) Forschungszentrum Jülich GmbH, Leo Brand Straße, Jülich, NRW 52425, Germany
AU: Kamai, T
EM: tkamai@ucdavis.edu
AF: Department of Land, Air and Water Resources, Veihmeyer Hall, Davis, CA 95616-8628, United States
AU: Harter, t
EM: ttharter@ucdavis.edu
AF: Department of Land, Air and Water Resources, Veihmeyer Hall, Davis, CA 95616-8628, United States
AU: Kasteel, R
EM: r.kasteel@fz-juelich.de
AF: Agrosphere (ICG-4) Forschungszentrum Jülich GmbH, Leo Brand Straße, Jülich, NRW 52425, Germany
AU: hopmans, j w
EM: jwhopmans@ucdavis.edu
AF: Department of Land, Air and Water Resources, Veihmeyer Hall, Davis, CA 95616-8628, United States
AU: vanderborght, j
EM: j.vanderborght@fz-juelich.de
AF: Agrosphere (ICG-4) Forschungszentrum Jülich GmbH, Leo Brand Straße, Jülich, NRW 52425, Germany
AB: Soil moisture is a key variable in understanding water and energy fluxes in terrestrial systems. The characterization of soil moisture variability is one of the major challenges in hydrological sciences today. Especially the relationship between soil moisture variability and mean soil water content is receiving considerable attention as it plays an important in upscaling and downscaling of soil moisture fields and in the parameterization of terrestrial and climate models. We show that the relationship between mean moisture content and its standard deviation can be predicted by stochastic analysis of unsaturated Brooks-Corey flow in heterogeneous soils. Based on a sensitivity analysis, it is found that parameters of the moisture retention characteristic and their spatial variability determine to a large extent the shape of the soil moisture variance-mean water content function. Predicting this function for eleven textural classes we found that the standard deviation of soil moisture peaked between 0.17 and 0.23 for most textural classes. Differing values were found for the more sandy soils. The simulated range of soil moisture agrees with field findings reported in the literature. It was found that pore-size distribution of soils is the primary parameter controlling the maximum value of the soil moisture standard deviation. We demonstrate the potential of inversely estimating soil hydraulic parameters and their statistics from soil moisture data using a case study with generated functions.
DE: 1839 Hydrologic scaling
DE: 1855 Remote sensing (1640)
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2007 Fall Meeting