Department of Statistical Science
Duke University
presents:
Zbigniew Kabala
kabala@copernicus.egr.duke.edu
Civil Engineering, Duke University
"Uncertainty in Subsurface Hydrology"
Abstract: Spatial variability in parameters characterizing porous media can be represented by random fields. The governing equations for contaminant transport through heterogeneous formations can thus be reinterpreted as stochastic partial differential equations (SPDE). Finding an associated governing equation for the evolution of the mean solute concentration and the concentration coefficient of variation is straightforward when the underlying SPDE is linear. However, it is much more challenging when the underlying SPDE is nonlinear. For reactive solutes the mean governing equation represents field-observed phenomena, such as transient field-scale dispersion and transient field-scale retardation, much better than the traditional deterministic models.
In a different vein, parameter estimation from hydrologic field tests can be significantly improved by calculating approximate joint confidence regions associated with the hydrologic models used for interpretation of the tests. Three nonlinear well response models are used to illustrate this point. The reliability of the approximate confidence regions is confirmed through synthetic Monte Carlo simulations.
January 23, 1998
3:30 pm - 4:30 pm
116 Old Chem Building Any questions concerning the seminar may be addressed to Cheryl McGhee @ [919] 684-8029 or e-mail cheryl@stat.duke.edu. Please contact the author(s) directly for reprints etc.