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@ARTICLE{Jadoon:3546,
      author       = {Jadoon, K. Z. and Slob, E. C. and Vanclooster, M. and
                      Vereecken, H. and Lambot, S.},
      title        = {{U}niqueness and {S}tability {A}nalysis of
                      {H}ydrogeophysical {I}nversion for {T}ime-{L}apse
                      {G}round-{P}enetrating {R}adar {E}stimates of {S}hallow
                      {S}oil {H}ydraulic {P}roperties},
      journal      = {Water resources research},
      volume       = {44},
      issn         = {0043-1397},
      address      = {Washington, DC},
      publisher    = {AGU},
      reportid     = {PreJuSER-3546},
      pages        = {W09421},
      year         = {2008},
      note         = {This work was supported by the Forschungszentrum Julich
                      GmbH (Germany), Fonds National de la Recherche Scientifique
                      (FNRS) and Universite Catholique de Louvain (Belgium), and
                      Delft University of Technology (Netherlands). The authors
                      are grateful to Marc Grasmueck, Niklas Linde, an anonymous
                      reviewer, and Fred Day-Lewis for their constructive comments
                      for improving the manuscript.},
      abstract     = {[1] Precise measurement of soil hydraulic properties at
                      field scales is one of the prerequisites to simulate
                      subsurface flow and transport processes, which is crucial in
                      many research and engineering areas. In our study, we
                      numerically analyze uniqueness and stability for integrated
                      hydrogeophysical inversion of time-lapse, off-ground
                      ground-penetrating radar (GPR) data in estimating the
                      unsaturated soil hydraulic properties. In the inversion,
                      hydrodynamic modeling based on the one-dimensional (1-D)
                      Richards equation is used to physically constrain a
                      full-waveform radar electromagnetic model. Synthetic GPR
                      data, in terms of 3-D multilayered media Green's functions,
                      were generated for three different textured soils (coarse,
                      medium, and fine) and assuming different infiltration
                      events. Inversion was performed iteratively to estimate
                      three key soil hydraulic parameters (alpha,n, and K-s) of
                      the Mualem-van Genuchten model using the global multilevel
                      coordinate search optimization algorithm. For the coarse-
                      and medium-textured soils, inversions converged to the
                      actual solution for all scenarios. For the fine soil,
                      estimation errors occurred, mainly because of the higher
                      attenuation of the electromagnetic waves in such a soil
                      (high electric conductivity). The procedure appeared to be
                      generally stable with respect to possible errors in the
                      hydrodynamic and petrophysical model parameterization.
                      However, we found that particular attention should be given
                      to an accurate estimation of the saturated water content and
                      infiltration flux for real field applications. The results
                      from our numerical experiments suggest that, in theory, the
                      proposed method is promising for the noninvasive
                      identification of the shallow soil hydraulic properties at
                      the field scale with a high spatial resolution.},
      keywords     = {J (WoSType)},
      cin          = {ICG-4 / JARA-ENERGY / JARA-SIM},
      ddc          = {550},
      cid          = {I:(DE-Juel1)VDB793 / $I:(DE-82)080011_20140620$ /
                      I:(DE-Juel1)VDB1045},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Environmental Sciences / Limnology / Water Resources},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000259399900003},
      doi          = {10.1029/2007WR006639},
      url          = {https://juser.fz-juelich.de/record/3546},
}