Inverse modeling of dynamic nonequilibrium in water flow with an effective approach

摘要: [1] Observations of water flow in unsaturated soils often show “dynamic effects,” indicated by nonequilibrium between contents and potential, a phenomenon that cannot be modeled with the Richards equation. The objective this article is to formulate an effective process description dynamic variably saturated soil which both flexible enough match experimental observations as parsimonious possible allow unique parameter estimation inverse modeling. In conceptual model, content partitioned into two fractions. Water one fraction equilibrium pressure head, whereas second nonequilibrium, described kinetic equilibration approach Ross Smettem (2000). Between fractions instantaneous head assumed. new termed dual-fraction requires only additional compared Smettem. We tested model data from multistep outflow experiments conducted on it equation, Smettem, dual-porosity Philip (1968). were evaluated modeling using robust Markov chain Monte Carlo sampler. results proposed superior equation describing effects occurring experiments. three popular selection criteria (Akaike information criterion, Bayesian deviance criterion) all favored because its smaller number parameters.