HR: 08:00h
AN: H21G-01 INVITED     [Abstracts]
TI: Non-invasive methods to study flow and transport at the soil core and lysimeter scale
AU: * Vereecken, H
EM: h.vereecken@fz-juelich.de
AF: Harry Vereecken Agrosphere Institute Forschungszentrum Juelich GmbH, Leo-Brandstraáe, Juelich, NRW 52428 Germany
AB: Non-invasive methods offer a great potential to study flow and transport processes at the core to the field and regional scale. In this contribution we will focus on the application of selected techniques such as MRI (Magnetic Resonance Imaging), X-Ray-Tomography (X-RT), MERIT (Magnetic Electrical Resistivity Imaging Technique), GPR (Ground Penetrating Radar) and Spectral Induced Polarisation (SIP) at the core to lysimeter scale. MRI is a powerful tool to derive local scale transport parameters. Based on the imaging of the 3-D temporal evolution of the spatial moments of a solute transport in a soil core, the local scale dispersivity of the soil can be derived. We also use MRI to image the root distribution inside a packed soil column. We employ the effect that the transverse relaxation time of water in the porous medium is considerably smaller than in the root tissue of rizinus communis. Different MRI pulse sequences were tested showing that the best contrast is obtainable by the strongly T2* weighted method CISS. X-RT provides information on the structure of the porous media. By parametrizing this structural information we may obtain an improved description of solute transport in undisturbed soil cores. GPR allows to map the spatial and temporal distribution of soil moisture in large undisturbed lysimeters. Combined with outflow data, this provides unique information to evaluate and improve mathematical models. New developments like MERIT are on their way which additionally exploits the magnetic information inherent in Electrical Resistivity Tomography-experiments to improve the spatial distribution of solute concentrations at lysimeter scale. SIP methods may be used to derive local scale pore size distribution and hydraulic conductivity. The single relaxation times, deduced from a measured phase spectrum either via multi-Cole-Cole-fits or as a whole relaxation time distribution, are a function of the relaxation length, which is connected to pore space respectively particle size distribution. From this information hydraulic conductivity may be derived using theoretical considerations.
UR: http://www.fz-juelich.de
DE: 5100 PHYSICAL PROPERTIES OF ROCKS
DE: 1832 Groundwater transport
DE: 1894 Instruments and techniques
DE: 0400 Biogeosciences
DE: 0900 EXPLORATION GEOPHYSICS
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting