Filters: Tags: permafrost (X)274 results (10ms)
Ice wedge in permafrost exposed by placer mining near Livengood, northwest of Fairbanks, Alaska. 1949.
Ice wedge (ground ice) in permafrost exposed by placer mining near Livengood, about 50 miles northwest of Fairbanks, Alaska. Photo by T.L. Pewe. September 1949.
Vector line dataset displaying the extent of sea ice and subsea permafrost in the northern hemisphere. This is a companion dataset to the Circum-Arctic Map of Permafrost and Ground Ice Conditions .
This pilot project has initiated a long-term integrated modeling project that aims todevelop a dynamically linked model framework focused on climate driven changes tovegetation, disturbance, hydrology, and permafrost, and their interactions and feedbacks.This pilot phase has developed a conceptual framework for linking current state-of-thesciencemodels of ecosystem processes in Alaska – ALFRESCO, TEM, GIPL-1 – and theprimary processes of vegetation, disturbance, hydrology, and permafrost that theysimulate. A framework that dynamically links these models has been defined and primaryinput datasets required by the models have been developed.
Potential Evapotranspiration (PET): These data represent decadal mean totals of potential evapotranspiration estimates (mm). The file name specifies the decade the raster represents. For example, a file named pet_mean_mm_decadal_MPI_ECHAM5_A1B_annual_2000-2009.tif represents the decade spanning 2000-2009. The data were generated by using the Hamon equation and output from ECHAM5, a fifth generation general circulation model created by the Max Planck Institute for Meteorology in Hamburg Germany. Data are at 2km x 2km resolution, and all data are stored in geotiffs. Calculations were performed using R 2.12.1 and 2.12.2 for Mac OS Leopard, and data were formatted into geotiffs using the raster and rgdal packages. Users...
These raster datasets represent historical stand age. The last four digits of the file name specifies the year represented by the raster. For example a file named Age_years_historical_1990.tif represents the year 1990. Cell values represent the age of vegetation in years since last fire, with zero (0) indicating burned area in that year. Files from years 1860-2006 use a variety of historical datasets for Boreal ALFRESCO model spin up and calibration to most closely match historical wildfire dynamics.
The Integrated Ecosystem Model is designed to help resource managers understandthe nature and expected rate of landscape change. Maps and other products generated by theIEM will illustrate how arctic and boreal landscapes are expected to alter due to climate-drivenchanges to vegetation, disturbance, hydrology, and permafrost. The products will also provideresource managers with an understanding of the uncertainty in the expected outcomes.
This raster, created in 2010, is output from the Geophysical Institute Permafrost Lab (GIPL) model and represents simulated active layer thickness (ALT) in meters averaged across a decade. The file name specifies the decade the raster represents. For example, a file named ALT_1980_1989.tif represents the decade spanning 1980-1989. Cell values represent simulated maximum depth (in meters) of thaw penetration (for areas with permafrost) or frost penetration (for areas without permafrost). If the value of the cell is positive, the area is underlain by permafrost and the cell value specifies the depth of the seasonally thawing layer above permafrost. If the value of the cell is negative, the ground is only seasonally...
Permafrost zonation and climate change in the northern hemisphere: Results from transient general circulation models
Holocene climate and the development of a subarctic peatland near Inuvik, Northwest Territories, Canada
Methane emissions from wetlands in the zone of discontinuous permafrost: Fort Simpson, Northwest Territories, Canada
High Arctic Frost-Creep/Gelifluction Slope, 1981-89: Resolute Bay, Cornwallis Island, Northwest Territories, Canada
Map of the Fish and Judy Creek Area and location of proposed observation sites (numbered circles). Fish Creek, Judy Creek, and the Ublutuoch River are almost entirely within the Beaufort Coastal Plain Ecoregion, though a small portion of Judy Creek extends into the Brooks Foothills. Inset shows the location of the seven TEON focal watersheds. Image by Arctic LCC staff.
Our objective is to improve the scientific understanding of the modes, rates, and mechanisms of carbon stabilization and losses in soils from Alaska, California, and other Western states. We focus on the biophysical and microbial mechanisms that drive carbon gains and losses, and to use our data to improve models of soil carbon cycling. This catalog supports research from several projects focused on soil carbon cycling. It encompasses multiple types of datasets including environmental, ecological, biological, isotopic, mineralogical, genomic, flux, and modeled data from water, vegetation, soil, and atmospheric matrices. The catalog will be available online and to the public. Therefore, publication of data through...
Abstract (from http://onlinelibrary.wiley.com/doi/10.1111/gcb.12875/abstract): Permafrost thaw can alter the soil environment through changes in soil moisture, frequently resulting in soil saturation, a shift to anaerobic decomposition, and changes in the plant community. These changes, along with thawing of previously frozen organic material, can alter the form and magnitude of greenhouse gas production from permafrost ecosystems. We synthesized existing methane (CH 4) and carbon dioxide (CO 2) production measurements from anaerobic incubations of boreal and tundra soils from the geographic permafrost region to evaluate large-scale controls of anaerobic CO 2 and CH 4 production and compare the relative importance...
Survey of geology, geologic materials, and geologic hazards in proposed access corridors in selected quadrangles, Alaska
As part of the Department of Natural Resources (DNR) effort to make final recommendations of federal land parcels to be considered for selection by the State of Alaska according to provisions of the Statehood Act, a decision was made to identify and evaluate potential access corridors. Corridor maps were compiled for a total of 78 quadrangles throughout Alaska. This map suite shows relevant geologic information at a scale of 1:250,000 for 10-mile-wide corridors straddling centerlines for proposed access routes throughout Alaska. The maps are based on geologic data compiled from existing, published mapping. Each compiled corridor geology map was used to derive maps of potential construction materials, data quality,...
During 2009, the Alaska Division of Geological & Geophysical Surveys continued a program, begun in 2006, of reconnaissance mapping of surficial geology in the proposed natural-gas pipeline corridor through the upper Tanana River valley. The study area is a 12-mi-wide (19.3-km-wide) area that straddles the Alaska Highway from the western boundaries of the Tanacross B-3 and A-3 quadrangles near Tetlin Junction eastward to the eastern boundaries of the Nabesna D-1 and C-1 quadrangles along the Canada border. Mapping during 2008-2009 in the Tanacross and Nabesna quadrangles linked with the mapping completed in the Tanacross, Big Delta and Mt. Hayes quadrangles in 2006-2008. Surficial geology was initially mapped in...
This map illustrates extents and types of unconsolidated deposits and bedrock in the Big Delta A-4 Quadrangle, Alaska. This map is based on field observations begun by P�w� in 1949 and by Reger in 1976. Unit characteristics and extents were determined during field visits and by interpreting 1:40,000-scale black-and-white aerial photographs taken in August 1949 and 1:63,360-scale, false-color infrared aerial photographs taken in July 1978, August 1980, and August 1981.
Vulnerability of shorebird and waterfowl habitat in the Yukon Kuskokwim Delta: assessing landscape dynamic in response to climate change
The YKD is also home to the largest subsistence-based economy in Alaska. Yet, the low-lying landscape mosaic characterizing the YKD is at risk of massive change associated with projected sea level rise (SLR), increasing storm frequency and severity and permafrost degradation due to future climate change. Therefore, to conserve ecosystem services associated with the botanical and faunal richness in the YKD, management strategies in the region should not only be based on current ecosystem conditions, but also incorporate projected changes in landscape composition. The goal of this project is to provide managers and people living in the YKD, an assessment of the vulnerability of the landscape to future change and to...
This project established a permafrost monitoring network in this region, providing a baseline of permafrost thermal regimes for assessing future change at a total of 26 automated monitoring stations. Stations have collected year-round temperature data from the active layer and the permafrost starting from the summer of 2011. The strong correspondence between spatial variability in permafrost thermal regime and an existing ecotype map allowed for the development of a map of ‘permafrost thermal classes’ for the broader study region. Further, the annual temperature data was used to calibrate models of soil thermal regimes as a function of climate, providing estimates of both historic and future permafrost thermal regimes...