Author(s)

G. Niitzmann & M. Thiele

Abstract

Parameter estimation for unsaturated flow models using sensitivity analysis G. Niitzmann & M. Thiele Institute of Freshwater Ecology and Inland Fisheries, Rudower Chaussee 6A, D-12484 Berlin, Germany Abstract The results of several multi-step outflow experiments on a 150-cm column were analyzed to identify the unsaturated hydraulic properties of a coarse-textured sandy soil. The hydraulic functions are assumed to be represented by the complete van Genuchten - Mualem closed-form expressions with variable coefficients a, n, and m. A sensitivity analysis with respect to these parameters shows, that conditions of local identifiability are satisfied if exclusively measurements of water content in some inner points of the column are considered. For this porous medium unique results of the identification problem could be obtained, and afterwards, the corresponding hydraulic functions have been verified with respect to additional drainage experiments. 1 Introduction M

Keywords