A new soil moisture scheme has been incorporated into the CSIRO Atmospheric Research Limited Area Model (DARLAM). The new model solves Richard's equations for soil moisture transport over 6 soil layers and includes high resolution data sets of surface properties. The model is being used to study the evolution of soil moisture patterns over the continent during the period 1993-1995.
DARLAM has an extensive set of physical parameterizations. Long-wave and short-wave radiative contributions are provided by a recent version of the Fels and Schwartzkopf (1975) scheme, with radiative clouds diagnosed from relative humidity. The cumulus convection scheme is a modified Arakawa (1972) mass flux scheme. Vertical mixing and surface transfer processes follow Louis (1979). At the surface, the model adopts the canopy scheme of Kowalczyk et al. (1994) which includes 31 vegetation types. The latent and sensible heat fluxes from the ground are parameterized using Monin-Obukhov similarity theory.
For this study the atmospheric meteorological variables were forced by ECMWF analyses, while surface variables such as soil moistures and temperatures evolved freely.
This assessment concentrates on surface variables associated with the water budget and the surface energy balance.