The two models had the similar accuracy of water flux simulations. Precipitation time series demonstrated a low complexity and a relatively high information content. Both models simulated behavior of soil as an information filter with respect to water fluxes. Simulated soil water flux time series had smaller information content as compared with precipitation time series. The complexity of simulated water flux time series was higher than the complexity of precipitation time series, so that the water flux time series appeared to be more structured as compared with precipitation time series.
Model outputs showed distinct differences in their relationships between complexity and information content. Overall, more complex simulated soil flux time series were obtained with the HYDRUS-1D model that used a continuum mechanics representation of soil water flow and was perceived to be conceptually more complex than the WMBUS model. The MWBUS model generated flux time series that had the range of complexity measure values much narrower than the HYDRUS -1D model. An increase in the complexity of water flux time series occurred in parallel with the decrease in the information content.
An increase in complexity of the conceptual soil water flow models is often being associated with considering a layered flow domain instead of a single homogeneous layer. For one, this definitely causes an increase in the number of parameters, as each layer has its own set of soil hydraulic properties. We ran fifty Monte Carlo simulations of soil water fluxes for the single soil homogeneous layer. The information content and complexity of simulated soil water fluxes appeared to be affected by the type of water flow transport mechanism descriptions rather than by the variation of parameters within the flow domain.
The good model discrimination was achieved when both information content and complexity measures were used to characterize the simulated time series. Using the effective measure complexity in combination with the mean information gain was the most efficient way to discriminate models in this work.
Keywords: soil water flow simulations, information, complexity, water flux, model comparison