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| Titel |
Comparison of 3D ground-penetrating radar simulations with measurements on the ASSESS-GPR test site |
| VerfasserIn |
Jorrit Fahlke, Jens Buchner, Olaf Ippisch, Kurt Roth, Peter Bastian |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052454
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| Zusammenfassung |
| We present 3D simulations of ground-penetrating radar (GPR) measurements of a real-world
setup. We use the wave equation of the electric field in the time-domain to model the physical
problem. For discretization we use a finite-element time-domain (FETD) method with
conforming edge-based finite elements. While finite-differences time-domain (FDTD) solvers
are faster, the use of FETD allows us to resolve complicated structures and avoid staircase
approximations. This way we can fit the finite element mesh to the layer structure of the
experimental setup.
We gain real data from the ASSESS-GPR test site near Heidelberg, a 20 m x 4 m x 2 m
body artificially packed with different sands. The architecture consists of several
layers and includes different slopes and a wedge. The site is instrumented with an
array of TDR-probes for local measurements of liquid water content and with a
corresponding array of temperature-probes. At the lower boundary, a well-defined
water table is maintained. Water flow is driven by natural rainfall and evaporation,
monitored by an on-site weather station. The hydraulic dynamics of the site is simulated
numerically such that the spatial structure of the dielectric permittivity is reasonably well
known.
Finally, we compare the results obtained from the simulation with results obtained from
real GPR measurements.
The software for the simulation has been developed using the Distributed and
Unified Numerics Environment (DUNE) and its PDELab discretization module. This
allowed us to write a uniform implementation for both 2D and 3D problems. The
3D-implementation has been parallelized using MPI to make computations of this size
feasible. |
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