% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Klotzsche:11994,
      author       = {Klotzsche, A. and van der Kruk, J. and Meles, G.A. and
                      Doetsch, J. and Maurer, H. and Linde, N.},
      title        = {{F}ull-waveform inversion of cross-hole ground-penetrating
                      radar data to characterize a gravel aquifer close to the
                      {T}hur {R}iver, {S}witzerland},
      journal      = {Near surface geophysics},
      volume       = {8},
      issn         = {1569-4445},
      address      = {Houten},
      publisher    = {EAGE},
      reportid     = {PreJuSER-11994},
      pages        = {635 - 649},
      year         = {2010},
      note         = {This work was initiated as an MSc project within the Joint
                      Master programme for Applied Geophysics of the Idea League,
                      involving the universities TU Delft, ETH Zurich and RWTH
                      Aachen (http://www.idealeague.org/geophysics). We thank
                      Jacques R. Ernst for helpful discussions and advice. An
                      internal review by Stewart Greenhalgh greatly improved the
                      manuscript. We are indebted to our collaborators within the
                      RECORD project and also wish to thank Ludovic Baron for
                      performing borehole deviation logging. Funding for this
                      study was provided by the Swiss National Science Foundation
                      (SNF) and the ETH Competence Center for Environment and
                      Sustainability (CCES). Further, we want to acknowledge Brian
                      Wylie and Zoltan Szebenyi from the JSC at the Research
                      Center Julich for their help in implementing the code on the
                      JUMP cluster. We would also like to thank the Center for
                      Computing and Communication from the RWTH Aachen for the use
                      of the HPC-Cluster for our calculations. One of us (A.
                      Klotzsche) also wishes to thank Wintershall Holding AG for
                      providing a scholarship to support her studies.},
      abstract     = {Cross-hole radar tomography is a useful tool for mapping
                      shallow subsurface electrical properties viz. dielectric
                      permittivity and electrical conductivity. Common practice is
                      to invert cross-hole radar data with ray-based tomographic
                      algorithms using first arrival traveltimes and first cycle
                      amplitudes. However, the resolution of conventional standard
                      ray-based inversion schemes for cross-hole
                      ground-penetrating radar (GPR) is limited because only a
                      fraction of the information contained in the radar data is
                      used. The resolution can be improved significantly by using
                      a full-waveform inversion that considers the entire
                      waveform, or significant parts thereof. A recently developed
                      2D time-domain vectorial full-waveform crosshole radar
                      inversion code has been modified in the present study by
                      allowing optimized acquisition setups that reduce the
                      acquisition time and computational costs significantly. This
                      is achieved by minimizing the number of transmitter points
                      and maximizing the number of receiver positions. The
                      improved algorithm was employed to invert cross-hole GPR
                      data acquired within a gravel aquifer (4-10 m depth) in the
                      Thur valley, Switzerland. The simulated traces of the final
                      model obtained by the full-waveform inversion fit the
                      observed traces very well in the lower part of the section
                      and reasonably well in the upper part of the section.
                      Compared to the ray-based inversion, the results from the
                      full-waveform inversion show significantly higher resolution
                      images. At either side, 2.5 m distance away from the
                      cross-hole plane, borehole logs were acquired. There is a
                      good correspondence between the conductivity tomograms and
                      the natural gamma logs at the boundary of the gravel layer
                      and the underlying lacustrine clay deposits. Using existing
                      petrophysical models, the inversion results and
                      neutron-neutron logs are converted to porosity. Without any
                      additional calibration, the values obtained for the
                      converted neutron-neutron logs and permittivity results are
                      very close and similar vertical variations can be observed.
                      The full-waveform inversion provides in both cases
                      additional information about the subsurface. Due to the
                      presence of the water table and associated
                      refracted/reflected waves, the upper traces are not well
                      fitted and the upper 2 m in the permittivity and
                      conductivity tomograms are not reliably reconstructed
                      because the unsaturated zone is not incorporated into the
                      inversion domain.},
      keywords     = {J (WoSType)},
      cin          = {ICG-4},
      ddc          = {550},
      cid          = {I:(DE-Juel1)VDB793},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Geochemistry $\&$ Geophysics},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000285399200020},
      doi          = {10.3997/1873-0604.2010054},
      url          = {https://juser.fz-juelich.de/record/11994},
}