Investigation of vegetation,snow,permafrost,climate interactions for improved predictions of the permafrost thermal regime

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This northern field research seeks to understand how different climates and vegetation types will affect snow and soil physical properties such as thermal conductivity and, for snow, specific surface area, and how this will in turn modify the permafrost thermal regime. In a warming climate, permafrost thawing, by releasing greenhouse gases, will positively feedback on climate and the strength of this feedback is today poorly constrained. We will perform snow and soil measurements at two northern sites with vegetation ranging from forest tundra to herb tundra in the high Arctic. The selected sites are Umiujaq (56°N) in Nunavik and Bylot Island (73°N) in Nunavut, north of Baffin Island. Measurements will include permanent monitoring of snow and soil thermal conductivity and temperature vertical profiles, and soil humidity and thermal diffusivity. We will also perform radiation measurements and benefit from existing atmospheric measurements, so that we will be able to fully constrain the energy budget of the surface and of the ground. Winter field trips will measure snow density and specific surface area profiles and investigate the spatial variability of all the above variables. Summer field trips will study soil properties and their variability, as well as vegetation assemblages and their relationship to snow properties. Two stations have already been deployed in forest tundra and shrub tundra at Umiujaq and we will deploy one additional station at Bylot in 2013. Data acquisition will last throughout the project and hopefully beyond, adding a snow dimension to the already rich data base kept by Centre d'Etude Nordiques at Laval. We will attempt to involve local communities in this work, in particular by involving them in regular measurements of snow density and temperature profiles.