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@ARTICLE{Jadoon:255613,
      author       = {Jadoon, Khan Zaib and Weihermüller, Lutz and McCabe, M. F.
                      and Moghadas, D. and Vereecken, Harry and Lambot, S.},
      title        = {{T}emporal {M}onitoring of the {S}oil {F}reeze-{T}haw
                      {C}ycles over a {S}now-{C}overed {S}urface by {U}sing
                      {A}ir-{L}aunched {G}round-{P}enetrating {R}adar},
      journal      = {Remote sensing},
      volume       = {7},
      issn         = {2072-4292},
      address      = {Basel},
      publisher    = {MDPI},
      reportid     = {FZJ-2015-05752},
      pages        = {12041-12056},
      year         = {2015},
      abstract     = {We tested an off-ground ground-penetrating radar (GPR)
                      system at a fixed location over a bare agricultural field to
                      monitor the soil freeze-thaw cycles over a snow-covered
                      surface. The GPR system consisted of a monostatic horn
                      antenna combined with a vector network analyzer, providing
                      an ultra-wideband stepped-frequency continuous-wave radar.
                      An antenna calibration experiment was performed to filter
                      antenna and back scattered effects from the raw GPR data.
                      Near the GPR setup, sensors were installed in the soil to
                      monitor the dynamics of soil temperature and dielectric
                      permittivity at different depths. The soil permittivity was
                      retrieved via inversion of time domain GPR data focused on
                      the surface reflection. Significant effects of soil dynamics
                      were observed in the time-lapse GPR, temperature and
                      dielectric permittivity measurements. In particular, five
                      freeze and thaw events were clearly detectable, indicating
                      that the GPR signals respond to the contrast between the
                      dielectric permittivity of frozen and thawed soil. The
                      GPR-derived permittivity was in good agreement with sensor
                      observations. Overall, the off-ground nature of the GPR
                      system permits non-invasive time-lapse observation of the
                      soil freeze-thaw dynamics without disturbing the structure
                      of the snow cover. The proposed method shows promise for the
                      real-time mapping and monitoring of the shallow frozen layer
                      at the field scale.},
      cin          = {IBG-3},
      ddc          = {620},
      cid          = {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)16},
      UT           = {WOS:000362511400050},
      doi          = {10.3390/rs70912041},
      url          = {https://juser.fz-juelich.de/record/255613},
}