Arctic tundra landscapes exist as a mosaic of vegetation (graminoid-, dwarf-shrub and lichen-dominated) related to topography, soil type and hydrology (wet, mesic, dry tundra). The key driver of this fine-scale mosaic is the pattern, depth and duration of snow-lie. Changes in snow-lie within the landscape, resulting from climate change, may alter the vegetation and soils of the tundra regions that modulate fluxes of trace gases (CO2 and CH4, H2O) between tundra and atmosphere. Current models do not take account of this. Our key objective is therefore to improve quantification of seasonal trace gas flux and energy balance between surface and atmosphere at the landscape scale in high latitude tundra, and the potential feedbacks to radiative forcing of climate, taking into account this fine-scale landscape mosaic mediated by the dynamics of winter snow cover and its duration.