% 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{Kelter:856109,
      author       = {Kelter, Matthias and Huisman, Johan Alexander and
                      Zimmermann, Egon and Vereecken, H.},
      title        = {{F}ield evaluation of broadband spectral electrical imaging
                      for soil and aquifer characterization},
      journal      = {Journal of applied geophysics},
      volume       = {159},
      issn         = {0926-9851},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier Science},
      reportid     = {FZJ-2018-05755},
      pages        = {484 - 496},
      year         = {2018},
      abstract     = {Spectral electrical impedance tomography (EIT) involves the
                      imaging of the complex electrical distribution in the mHz to
                      kHz range. Until now, field EIT measurements were limited to
                      frequencies below 100 Hz because strong electromagnetic
                      coupling effects associated with longer cables and high
                      electrode contact impedances prohibit accurate field
                      measurements at higher frequencies. In this paper, we aim to
                      evaluate the capability of recent improvements in the
                      pre-processing and inversion of wideband EIT measurements to
                      improve the accuracy and spectral consistency of field EIT
                      measurements of the complex electrical conductivity
                      distributions in the mHz to kHz frequency range. In a first
                      case study, time-lapse surface EIT measurements were
                      performed during an infiltration experiment to investigate
                      the spectral complex electrical conductivity as a function
                      of water content. State-of-the-art data processing and
                      inversion approaches were used to obtain images of the
                      complex electrical conductivity in a frequency range from
                      100mHz to 1 kHz, and integral parameters were obtained
                      using Debye decomposition. Results showed consistent
                      spectral and spatial variation of the phase of the complex
                      electrical conductivity in a broad frequency range, and a
                      complex dependence on water saturation. In a second case
                      study, borehole EIT measurements were made in a
                      well-characterized gravel aquifer. These measurements were
                      inverted to obtain broadband images of the complex
                      conductivity after correction of inductive coupling effects
                      using a recently developed correction procedure that relies
                      on a combination of calibration measurements and model-based
                      corrections. The inversion results were spatially and
                      spectrally consistent in a broad frequency range up to
                      1 kHz only after removal of inductive coupling effects.
                      Overall, it was concluded that recent improvements in
                      spectral EIT measurement technology combined with advances
                      in inversion and data processing now allow accurate
                      broadband EIT measurements up to 1 kHz.},
      cin          = {IBG-3 / ZEA-2},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IBG-3-20101118 / I:(DE-Juel1)ZEA-2-20090406},
      pnm          = {255 - Terrestrial Systems: From Observation to Prediction
                      (POF3-255)},
      pid          = {G:(DE-HGF)POF3-255},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000453644600048},
      doi          = {10.1016/j.jappgeo.2018.09.029},
      url          = {https://juser.fz-juelich.de/record/856109},
}