Abstract
Soil moisture is one of most important hydrological variables. Its redistribution have significant effects on evaporation, infiltration and groundwater recharge. Recently, its impacts on climate system is widely recognized. High non-linearity of Richards' equation makes its practical applications very difficult. Many soil moistue accounting hydrological models or land surface schemes (LSSs) take soil moisture into account conceptually as an index of wetness. Even Richards' equation based LSSs, used and evaluated in the global soil wetness project (GSWP) and/or the atmospheric model intercomparison project (AMIP), have only several soil layers. In order to develop a model to represent soil moisture redistribution in vertical direction for a better soil moisture accounting scheme, a high resolution numerical model solving vertical 1D Richards' equation is developed and applied to 9 soils in this study. By analyzing the soil moisture movement derived, two fomulae are proposed with parameters estimated from soil parameters. It is shown that these fomulae represented the behavior of soil water in soil column and at the surface fairly well.
