on snow and runoff

Observational and modelling studies show that the warming of the Arctic is lead-ing to shrub expansion. This shift in vegetation cover is expected to significantly alter the distribution of snow across the landscape and the interactions between the land surface and the atmosphere. Shrubs capture wind-blown snow, increas-ing snow depth and decreasing winter water loss through sublimation, and bend beneath the weight of snow, affecting albedo. Snow is highly insulative and affects the soil hydrological and thermal properties. Therefore, as the snow-vegetation-soil interactions is expected to be at the core of feedback loops leading to further shrub expansion, there is a need for models to be able to simulate these processes accurately. Initially using the community land surface model JULES (Joint UK Land Environment Simulator) this study investigates the effects of shrub-tundra on snow and runoff. Alternative formulations of soil processes are proposed, which are better adapted to the representation of subgrid heterogeneity in cold regions than the current model formulation, and evaluated over the Abisko an