An improved simple snow-atmosphere-soil transfer model

Abstract

On the basis of a simple snow-atmosphere-soil transfer (SAST) model previously developed, this paper presents an improved snow-atmosphere-soil transfer (ISAST) model that has a new numerical scheme and an improved method of layering the snowpack. The new model takes the snow cover temperature and ice content in the snow cover as prognostic variables. This approach, which effectively solves the snow cover temperature distribution when the snow cover is melting or freezing, lessens the iteration time and computation time, which is important for GCM simulation. In this model, the snow cover is divided into three layers (ISAST3) or seven layers (ISAST7). The simulation results obtained using the ISAST7 model agree well with observations in terms of snow depth, snow equivalent water and snow cover lifetime at five Russian sites. The new ISAST model has better simulation capacity for snow cover than the previous SAST model. When the snow cover is deep, the simulation of the ISAST7 model is better than that of the ISAST3 model. Testing shows that our ISAST model is approximately 20% faster than the SAST model.