Monitoring Heat Transfer Across the Active Layer Above Permafrost in Alaska

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9308334 HINKEL Rising concentrations of carbon dioxide and other gases in the atmosphere are expected to cause global warming. The effects of warming are expected to be amplified and observable first in high latitudes. Current models predict that rapid warming will combine with increases in summer rainfall and winter snowfall in northwestern North America, conditions that may result in rapid degradation of permafrost throughout large parts of Alaska and northwestern Canada. Similar conditions may also persist in northern Eurasia. Although permafrost is not in direct contact with the atmosphere, seasonal snow cover, surface vegetation, and an organic mat serve as an active layer that buffers heat transfer. Energy passes through this active layer through convection and through non-convective processes (including evaporation and condensation, freezing and melting, and volatilization and sublimation), which consume or release latent energy. High-frequency measurements of temperature and water- ionic concentrations in soils conducted by the investigator in discontinuous permafrost regions covered by boreal forests in Alaska have indicated that the non-conductive processes can, under some circumstances, dominate heat transfers in freezing and thawing soils. This project will continue this line of research in both areas of discontinuous permafrost and expand it into Arctic areas where permafrost is continuous. Data will be collected at two different scales, with high-frequency monitoring of near-surface processes conducted at three sites. Measurements also will be taken in the upper levels of permafrost at the same sites in order to refine methods for observing changes in crucial variables in this critical zone. This research will make contributions from both substantive and methodological perspectives. It will add to general knowledge about the role of non-conductive processes within the buffering active layer above permafrost, especially as that la yer responds to changes in temperature and precipitation. Expansion of this line of research into the upper layers of permafrost will increase understandings of processes in this zone and will provide tests of the feasibility for new monitoring procedures that might have utility in many similar locales. ***