High-resolution RCMs represent formidable laboratories that can be put to use to further our understanding of the complex interactions and feedback that shape weather and climate of Canada’s Nordic and Arctic regions. We plan to undertake a series of experiments to quantify the role and importance of explicitly resolving processes taking place in the land and atmosphere components of the regional Earth System and the interactions between them as such interactions are paramount in determining our immediate living environment. The Canadian Nordic and Arctic regions with their innumerable lakes, wetlands, glaciers, rivers, snow-cover and permafrost, present distinct challenges to climate modelling. As grid meshes of models approach 10 km, regional water bodies and land-surface heterogeneities begin to be explicitly resolved, thus allowing realistic feedback processes that will increase the realism of climate simulations and improve climate-change projections. A recent study by Lawrence et al. (2008) showed that when Arctic sea ice is in rapid decline, the rate of predicted warming over surrounding land more than triples. This could result in important changes to the Canadian snow-cover and permafrost, which in turn can lead to changes in the regional hydrology.
Through methodically designed numerical experiments using the available modelling and observational tools, several important science questions relating to Canada’s climate will be addressed, such as: How do vegetation, lakes, snow-cover, permafrost and glaciers modulate Canada’s climate? What is the impact of retreating glaciers and reduced snow cover on regional hydrology? What formulation of the Great Lakes is required to adequately simulate the climate and hydrology of the region? Are current model formulations of snow-albedo feedback in agreement with observations? What resolution is required to adequately simulate lake-effect snow-belt, mountain snowpacks and glacier mass balance? How has terrestrial Arctic drainage changed in recent decades? What are the impacts of rapid ice-loss events on the hydrology and climate of the surrounding land region?