HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (17) Citing Articles via Google Scholar Google Scholar Articles by Bitterlich, S. Articles by Knabner, P. Search for Related Content PubMed Articles by Bitterlich, S. Articles by Knabner, P. GeoRef GeoRef Citation Agricola Articles by Bitterlich, S. Articles by Knabner, P. Related Collections Vadose Zone Processes and Chemical Transport

ORIGINAL RESEARCH

Inverse Estimation of the Unsaturated Soil Hydraulic Properties from Column Outflow Experiments Using Free-Form Parameterizations

^a Institute of Applied Mathematics, Univ. of Erlangen-Nuremberg, Martensstr. 3, 91058 Erlangen, Germany
^b Institute of Geoecology, Braunschweig Technical Univ., Langer Kamp 19c, 38106 Braunschweig, Germany
^* Corresponding author (w.durner{at}tu-bs.de)

Received 27 November 2003.

Inverse methods are increasingly used to estimate the hydraulic properties of unsaturated soils. The method generally uses a weighted least-squares approach in which numerically simulated data are fitted to measured data. In this study we used inverse methods to estimate the unsaturated soil hydraulic properties from continuous and multistep column outflow experiments. The method employs piecewise polynomial functions to obtain a free-form parameterization of the hydraulic properties, rather than fixed functional forms typical of the van Genuchten–Mualem and Brooks–Corey–Burdine models. For the polynomial functions we used quadratic B-splines and piecewise cubic Hermite interpolation. The method leads to local parameterizations that can also be hierarchic, depending on the invoked number of degrees of freedom. Since a suitable number of degrees of freedom cannot be defined a priori, we embedded the estimation method into a multilevel procedure, which also included a stability analysis, based on singular value decomposition of the sensitivity matrix. The optimization procedure was made more stable by imposing monotonicity constraints on the hydraulic functions. Tests with synthetic and measured data from column outflow experiments show the validity and robustness of the method.

This article has been cited by other articles:

				B. B. Mirus, K. S. Perkins, J. R. Nimmo, and K. Singha Hydrologic Characterization of Desert Soils with Varying Degrees of Pedogenesis: 2. Inverse Modeling for Effective Properties Vadose Zone J., May 21, 2009; 8(2): 496 - 509. [Abstract] [Full Text] [PDF]

				J. A. Vrugt, P. H. Stauffer, Th. Wohling, B. A. Robinson, and V. V. Vesselinov Inverse Modeling of Subsurface Flow and Transport Properties: A Review with New Developments Vadose Zone J., May 27, 2008; 7(2): 843 - 864. [Abstract] [Full Text] [PDF]

				G. Crescimanno and P. Garofalo Application and Evaluation of the SWAP Model for Simulating Water and Solute Transport in a Cracking Clay Soil Soil Sci. Soc. Am. J., October 27, 2005; 69(6): 1943 - 1954. [Abstract] [Full Text] [PDF]