A new snow model has been implemented into the CSIRO GCM. The emphasis in the recent model development has been to improve seasonal simulations of snow cover, as well as soil moisture and heat cycles for higher latitudes. The new snow model computes the temperature, snow density and thickness of three snowpack layers. The processes of snow accumulation, melting and physically based snow albedo are included. The previous snow scheme used a combined soil/snow layer and prescribed depth-dependent snow albedo. A parameterization of frozen soil moisture is also included.
The model has been tested in stand-alone mode using long-term observational data from the Valdai water-balance research station in the former Soviet Union. The results of simulation of snow cover are presented. The effects of snow cover evolution on the components of the soil hydrological budget are examined. The sensitivity of the results to various aspects of the model formulations is also discussed.