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@INPROCEEDINGS{Zimmermann:824160,
      author       = {Zimmermann, Egon and Huisman, Johan Alexander and Mester,
                      Achim and van Waasen, Stefan},
      title        = {{N}umerical correction of phase errors due to leakage
                      currents in wideband {EIT} measurements.},
      reportid     = {FZJ-2016-06781},
      year         = {2016},
      abstract     = {Advanced model-based data correction methods are needed in
                      order to determine the small phase response of
                      low-polarizable soils and rocks in the higher frequency
                      range up to 10 kHz. Methods have been developed to correct
                      several system-dependent errors, such as amplification
                      errors, signal drift, current measurement errors, potential
                      measurement errors due to high electrode impedances,
                      propagation delay of the signal due to the long cables, and
                      phase errors introduced by inductive coupling between the
                      electrode cables. However, measurements at test sites with
                      high resistivity have shown a new dominating phase error,
                      which was found to be related to capacitive leakage currents
                      between system ground and the soil. In order to correct this
                      error, we enhanced the FEM modelling used for the
                      reconstruction of the electrical conductivity distribution.
                      Using this new formulation of the FEM forward model, this
                      source of error was reduced by a factor of five or more.
                      This enables an electrical conductivity reconstruction for
                      frequencies up to 10 kHz. In future work, it will be
                      investigated whether the capacitive leakage currents can be
                      reduced by optimization of the cable layout. In any case, it
                      is helpful to use the leakage current as a proxy for data
                      error during data filtering, and it can also be used to
                      decide if the enhanced FEM model presented here should be
                      used.},
      month         = {Jun},
      date          = {2016-06-06},
      organization  = {4th International Workshop on Induced
                       Polarization, Aarhus (Denmark), 6 Jun
                       2016 - 8 Jun 2016},
      cin          = {ZEA-2 / IBG-3},
      cid          = {I:(DE-Juel1)ZEA-2-20090406 / I:(DE-Juel1)IBG-3-20101118},
      pnm          = {255 - Terrestrial Systems: From Observation to Prediction
                      (POF3-255)},
      pid          = {G:(DE-HGF)POF3-255},
      typ          = {PUB:(DE-HGF)1},
      url          = {https://juser.fz-juelich.de/record/824160},
}