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@ARTICLE{Klotzsche:866395,
      author       = {Klotzsche, Anja and Vereecken, Harry and van der Kruk, Jan},
      title        = {{R}eview of crosshole ground-penetrating radar
                      full-waveform inversion of experimental data: {R}ecent
                      developments, challenges, and pitfalls},
      journal      = {Geophysics},
      volume       = {84},
      number       = {6},
      issn         = {1942-2156},
      address      = {Alexandria, Va.},
      publisher    = {GeoScienceWorld},
      reportid     = {FZJ-2019-05549},
      pages        = {H13 - H28},
      year         = {2019},
      abstract     = {Heterogeneous small-scale high-contrast layers and spatial
                      variabilities of soil properties can have a large impact on
                      flow and transport processes in the critical zone. Because
                      their characterization is difficult and critical,
                      high-resolution methods are required. Standard ray-based
                      approaches for imaging the subsurface consider only a small
                      amount of the measured data and suffer from limited
                      resolution. In contrast, full-waveform inversion (FWI)
                      considers the full information content of the measured data
                      and could yield higher resolution images in the
                      subwavelength scale. In the past few decades,
                      ground-penetrating radar (GPR) FWI and its application to
                      experimental data have matured, which makes GPR FWI an
                      established approach to significantly improve resolution.
                      Several theoretical developments were achieved to improve
                      the application to experimental data from crosshole GPR FWI.
                      We have determined the necessary steps to perform FWI for
                      experimental data to obtain reliable and reproducible
                      high-resolution images. We concentrate on experimental
                      crosshole GPR data from a test site in Switzerland to
                      illustrate the challenges of applying FWI to experimental
                      data and discuss the obtained results for different
                      development steps including possible pitfalls. Thereby, we
                      acknowledge out the importance of a correct time-zero
                      correction of the data, the estimation of the effective
                      source wavelet, and the effect of the choice of starting
                      models. The reliability of the FWI results is investigated
                      by analyzing the fit of the measured and modeled traces, the
                      remaining gradients of the final models, and validating with
                      independently measured logging data. Thereby, we found that
                      special care needs to be taken to define the optimal
                      inversion parameters to avoid overshooting of the inversion
                      or truncation errors.},
      cin          = {IBG-3 / JARA-HPC},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IBG-3-20101118 / $I:(DE-82)080012_20140620$},
      pnm          = {255 - Terrestrial Systems: From Observation to Prediction
                      (POF3-255) / Better predictions with environmental
                      simulation models: optimally integrating new data sources
                      $(jicg41_20100501)$},
      pid          = {G:(DE-HGF)POF3-255 / $G:(DE-Juel1)jicg41_20100501$},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000501594400020},
      doi          = {10.1190/geo2018-0597.1},
      url          = {https://juser.fz-juelich.de/record/866395},
}