Heidelberg 2015 – wissenschaftliches Programm
UP 13.12: Poster
Donnerstag, 26. März 2015, 10:45–19:45, G/Foyer
Estimation of soil hydraulic material properties based on time-lapse Ground Penetrating Radar measurements — •Stefan Jaumann, Klenk Patrick, and Kurt Roth — Institute of Environmental Physics, Heidelberg University
Soil hydraulic material properties are needed for a large range of applications, such as the optimization of irrigation and fertilization for food production in semi arid regions. However, these material properties are (i) unknown a priori, (ii) nearly impossible to measure directly, (iii) varying in space and in time, and (iv) highly non-linear. Hence, the development of efficient methods allowing for cheap and reliable identification of these properties is crucial.
In this study, we observed the dynamic deformation of the capillary fringe with time-lapse Ground Penetrating Radar (GPR) while forcing the hydraulic system with a fluctuating water table.
We then estimated effective material properties of the subsurface material distribution comparing the time-lapse GPR measurements to numerical simulations using the Levenberg-Marquardt optimization algorithm.
The corresponding numerical simulation of the GPR response is based on three coupled models comprising (i) a hydraulic model (Richards equation) which is based on conservation of water volume and an empirical flux law, (ii) a electrodynamic model (Maxwell’s equations), and (iii) a petrophysical relationship relating the previous two via the dependency of the composite relative permittivity of the soil on the water content.