Abstract
Soil moisture is one of the most important hydrological variables. Its redistribution has significant effects on evaporation, infiltration and groundwater recharge. Recently, its impacts on climate system are widely recognized. High non-linearity of Richards’ equation makes its practical applications very difficult. Many soil moisture 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 thick 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 dimensionless 1D Richards’ equation is developed and applied to 12 soils. By analyzing the soil moisture derived, two fomulae are proposed with parameters which can be estimated from a soil parameter. It is shown that these fomulae represented the behavior of soil water in soil column and at the surface fairly well.
