Influence of Climate and Environmental Factors on the Thermal Regime of the Active Layer and Permafrost

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Permafrost is one of the primary components of the Arctic land-atmosphere-ice system. Recent unexpected discoveries of a large-amplitude temperature cycle in the permafrost and of large and systematic changes in active layer thicknesses (since 1986) indicate that the current understanding of climate-active layer-permafrost interactions needs improvement. These interactions are important because warmer air temperatures predicted in the Arctic from increases in greenhouse gases will cause permafrost to thaw as the active layer becomes thicker. A better understanding of the linkages between the atmosphere, soil surface, active layer, and permafrost is required to answer questions regarding the rate and extent of permafrost degradation, modifications to its thermal regime, release of carbon and trace gases by thawing permafrost, changes in soil moisture, the biota, the hydrological cycle, how these changes will influence the use of polar lands, and the development, calibration, and validation of small-scale numerical models (2 km grids) of land-atmosphere interactions that are to be nested in larger scale models. A permafrost research program is propose that combines field measurements, laboratory measurements, and analyses and interpretation of data to be obtained at six long-term study sites along a transect from Prudhoe Bay across the coastal plain and foothills into the Brooks Range. These sites are in undisturbed areas, span a wide range of permafrost, climatic, and environmental conditions, include drillholes in the permafrost (40 to 75 m in depth), and have a long time series of data (since 1983). This research will extend the time series of measurements at the sites and will focus on investigating how the active layer and continuous permafrost, in a variety of climatic and environmental setting, has responded and continues to respond to climate change. The primary thrust of the proposed research is to investigate the effects of climate (especially air temperatures, snow, wind and precipitation) and environmental factors (especially vegetation and surface morphology) and their interactions on the thermal and moisture regimes of the active layer and permafrost in an effort to answer questions raised by current research.