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The evolution of permafrost in cold regions is inextricably connected to hydrogeologic processes, climate, and ecosystems. Permafrost thawing has been linked to changes in wetland and lake areas, alteration of the groundwater contribution to streamflow, carbon release, and increased fire frequency. But detailed knowledge about the dynamic state of permafrost in relation to surface and groundwater systems remains an enigma. Here, we present the results of a pioneering 1,800 line-kilometer airborne electromagnetic survey that shows sediments deposited over the past 4 million years and the configuration of permafrost to depths of 100 meters in the Yukon Flats area near Fort Yukon, Alaska. The Yukon Flats is near the...
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We examined the effects of fire disturbance on permafrost degradation and thaw settlement across a series of wildfires (from ~1930 to 2010) in the forested areas of collapse-scar bog complexes in the Tanana Flats lowland of interior Alaska. Field measurements were combined with numerical modeling of soil thermal dynamics to assess the roles of fire severity and climate history in postfire permafrost dynamics. Field-based calculations of potential thaw settlement following the loss of remaining ice-rich permafrost averaged 0.6 m. This subsidence would cause the surface elevations of forests to drop on average 0.1 m below the surface water level of adjacent collapse-scar features. Up to 0.5 m of thaw settlement was...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Adaptation planning 1-Best management practices,
Modeling,
Monitoring 1-Changes in Plant and Animal Distribution: Ecosystems,
Monitoring 3-Improve Permafrost Mapping,
and Monitoring, All tags...
landscape scale conservation: Fire, Fewer tags
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Discontinuous permafrost in the North American boreal forest is strongly influenced by the effects of ecological succession on the accumulation of surface organic matter, making permafrost vulnerable to degradation resulting from fire disturbance. To assess factors affecting permafrost degradation after wildfire, we compared vegetation composition and soil properties between recently burned and unburned sites across three soil landscapes (rocky uplands, silty uplands, and sandy lowlands) situated within the Yukon Flats and Yukon-Tanana Uplands in interior Alaska. Mean annual air temperatures at our study sites from 2011 to 2012 were relatively cold (-5.5 degrees C) and favorable to permafrost formation. Burning...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Modeling,
Monitoring 3-Improve Permafrost Mapping,
Projecting Future States 1-Predict or Map the Impact of Changing Permafrost,
Relationship Understanding 2b-Effects of Fire on Ecosystems,
and Monitoring
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