Characteristics and evolution of discontinuous permafrost in northern Canada at multiple spatial scales

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Discontinuous permafrost can be thought of as a patchwork, with seasonally frozen areas and water bodies interfingering with patches of perennially frozen earth materials that vary in size, spatial concentration, thickness, depth to the permafrost table, and thermal regime. Some thin permafrost patches have mean temperatures just a few hundredths of a degree below 0°C, so their thaw due to recent and future climate warming may occur relatively rapidly. Others may take many decades to thaw following climatic warming unless affected simultaneously by changes in drainage. This research program will examine the variation in permafrost distribution and temperature characteristics at micro-, local and regional scales along transects in the Yukon and Labrador, extending from the zone of isolated patches (1-10% of the terrain underlain by permafrost) northward, or upward, to the zone of continuous permafrost (>90% of the terrain underlain by permafrost). The findings will address fundamental questions about the way ground temperature, and hence permafrost distribution, varies along climatic gradients. They will also examine how permafrost distribution changes as the climate warms. The results will assist in better representing discontinuous permafrost in global and regional climate models. In addition, they will be pertinent to predictions of the rate of thaw of permafrost and hence to the potential for positive feedback in the global climate system due to stored carbon release. A combination of field monitoring, geophysical techniques, computer modeling as well as traditional aerial photo interpretation and remote sensing will be used to carry out the research program. The work will involve the training of several graduate students, as well as collaboration with federal government, provincial and territorial-based researchers, and communities. The results are expected to be relevant to assessing the impacts of thawing permafrost on the hydrology and ecology of permafrost regions, as well as helping predict and mitigate the impacts of permafrost degradation on northern infrastructure and resource development.