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@ARTICLE{Erdal:111955,
      author       = {Erdal, D. and Neuweiler, I. and Huisman, J.A.},
      title        = {{E}stimating effective model parameters for heterogeneous
                      unsaturated flow using error models for bias correction},
      journal      = {Water resources research},
      volume       = {48},
      issn         = {0043-1397},
      address      = {Washington, DC},
      publisher    = {AGU},
      reportid     = {PreJuSER-111955},
      pages        = {W06530},
      year         = {2012},
      note         = {Record converted from VDB: 16.11.2012},
      abstract     = {Estimates of effective parameters for unsaturated flow
                      models are typically based on observations taken on length
                      scales smaller than the modeling scale. This complicates
                      parameter estimation for heterogeneous soil structures. In
                      this paper we attempt to account for soil structure not
                      present in the flow model by using so-called external error
                      models, which correct for bias in the likelihood function of
                      a parameter estimation algorithm. The performance of
                      external error models are investigated using data from three
                      virtual reality experiments and one real world experiment.
                      All experiments are multistep outflow and inflow experiments
                      in columns packed with two sand types with different
                      structures. First, effective parameters for equivalent
                      homogeneous models for the different columns were estimated
                      using soil moisture measurements taken at a few locations.
                      This resulted in parameters that had a low predictive power
                      for the averaged states of the soil moisture if the
                      measurements did not adequately capture a representative
                      elementary volume of the heterogeneous soil column. Second,
                      parameter estimation was performed using error models that
                      attempted to correct for bias introduced by soil structure
                      not taken into account in the first estimation. Three
                      different error models that required different amounts of
                      prior knowledge about the heterogeneous structure were
                      considered. The results showed that the introduction of an
                      error model can help to obtain effective parameters with
                      more predictive power with respect to the average soil water
                      content in the system. This was especially true when the
                      dynamic behavior of the flow process was analyzed.},
      keywords     = {J (WoSType)},
      cin          = {IBG-3},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Environmental Sciences / Limnology / Water Resources},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000306000600001},
      doi          = {10.1029/2011WR011062},
      url          = {https://juser.fz-juelich.de/record/111955},
}