Spatial data used for analysis of trends in the occurrence of erosion features caused by thaw in the five National Park Service units of the Arctic Inventory and Monitoring Network, Alaska

This data set consists of a geo-referenced digital map and attribute data derived from the publication 'Permafrost map of Alaska'. The map is presented at a scale of 1 to 2,500,000 and shows the correlation of physiographic province to presence of permafrost across the state of Alaska. The digital data were prepared under the U.S. Geological Survey Global Change Program, Land Data Systems - Arctic Land Processes Studies for display and analysis of terrain. The line work was captured by hand digitizing the source map, Ferrians, O.J., 1965, Permafrost map of Alaska - U.S. Geological Survey Miscellaneous Geologic Investigations Map I-445. Scale 1 to 2,500,000. The digital map was assembled and edited in ARC/INFO. The source map projection is polyconic. It is based on the Clarke 1866 ellipsoid with a central meridian of 150 W longitude. The data were geo-referenced from digitizer coordinates to the polyconic projection and then projected into an Albers Equal Area projection. The coastline was taken from the U.S Geological Survey, 1 to 2,000,000 scale Digital Line Graph data (U.S. Geological Survey, 1987). Attributes for the permafrost map were assigned. Metadata documentation was completed in 1996. The map units are closed polygons that are generalized in shape and size. They are defined in terms of their physiographic characteristics and association with permafrost. Each unit differs with respect to all other units and is uniquely identified as follows.11 Mountainous Area underlain by continuous permafrost12 Mountainous Area underlain by discontinuous permafrost13 Mountainous Area underlain by isolated masses of permafrost21 Lowland and Upland Area underlain by thick permafrost22 Lowland and Upland Area underlain by moderately thick to thin permafrost23 Lowland and Upland Area underlain by discontinuous permafrost24 Lowland and Upland Area underlain by numerous isolated masses of permafrost25 Lowland and Upland Area underlain by isolated masses of permafrost26 Lowland and Upland Area generally free of permafrostUse constraints - The U.S. Geological Survey should be acknowledged as the data source in products derived from these data. The data are general in nature and should not be used at a scale larger than 1 to 2,500,000, that of the original map. Users must assume responsibility to determine the usability of this data for their purposes. The use of these data is not restricted and may be interpreted by organizations, agencies, units of government or others; however, they are responsible for its appropriate application. Digital data files are periodically updated. Files are dated and users are responsible for obtaining the latest revisions of the data. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the agency regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. A copy of this map is presented on the CAPS Version 1.0 CD-ROM, June 1998.

Geophysical measurements were collected by the U.S. Geological Survey (USGS) at two sites in Interior Alaska in 2019 and 2020 for the purposes of imaging permafrost structure and quantifying variations in subsurface moisture content in relation to thaw features. In September 2019, electrical resistivity tomography (ERT) and downhole nuclear magnetic resonance (NMR) data were used to quantify permafrost characteristics across the shorelines of Big Trail Lake, a thermokarst lake outside of Fairbanks, Alaska. Three 222 m ERT survey lines were collected perpendicular to the North, East, and South shorelines, and two 110 m lines were collected parallel to the southeast and northeast shorelines. Models of electrical resistivity produced from these data revealed the distribution of frozen and thawed soil to depths of 10-40 m below the surface. NMR data were collected within two 2.3 m deep boreholes adjacent to the East and North perpendicular ERT survey lines in September 2019 and logged again in March 2020. Additional one-time NMR measurements of liquid water content were collected in September 2019 within the lakebed sediments (0-25 cm depth) in approximately 2.5 m lateral increments moving away from the shorelines in the East and North, between 0 and 12 m from shore. These NMR transects roughly coincided with the perpendicular ERT lines. A separate ERT survey was conducted at the Bonanza Creek LTER (Long Term Ecological Research) in September 2019 and was a repeat of a previous ERT survey done in the same exact location three years prior. The survey line was 125 m in length and spanned the transition between burned and unburned forest. Models of electrical resistivity for this site imaged the structure of frozen and thawed soils to depths of 10-15 m. At both sites, manual permafrost-probe measurements of thaw depths were collected at set intervals along each ERT transect and used for comparison to the resistivity models.

Geophysical measurements were collected by the U.S. Geological Survey (USGS) at five sites in Interior Alaska in September 2021 for the purposes of imaging permafrost structure and quantifying variations in subsurface moisture content in relation to thaw features. Electrical resistivity tomography (ERT) measurements were made along transects 110-222 meters (m) in length to quantify subsurface permafrost characteristics. ERT transects were collected across a fireline boundary within the Bonanza Creek Long Term Ecological Research (LTER) site where repeat measurements have been made since 2014; across and adjacent to two thermokarst lakes, Vault Lake and Goldstream Lake; and along two profiles at the North Star golf course in Fairbanks, Alaska. Models of electrical resistivity produced from these data revealed the distribution of frozen and thawed soil to depths of 10-40 m below the surface. Borehole nuclear magnetic resonance (NMR) data were collected at two sites in order to determine liquid water content at depth in shallow boreholes. NMR data were collected in a 2.25 m-deep borehole at the North Star golf course adjacent to one of the ERT profiles, and in another two 1.625 m-deep boreholes adjacent to Big Trail Lake where previous NMR measurements were made in 2019 and 2020. Manual permafrost-probe measurements of thaw depths were collected at set intervals along each ERT transect and adjacent to NMR measurement locations used for comparison to the geophysical measurements, except at the North Star golf course where shallow permafrost was absent.

This dataset provides field observations of thaw depth and dominant vegetation types, a LiDAR-derived elevation map, and permafrost distribution and probability maps for an area on the coastal plain of the Yukon-Kuskokwim Delta (YKD), in western Alaska, USA. Field data were collected during July 8-17, 2016 to parameterize and to validate the derived permafrost maps. The YKD is in the sporadic to isolated permafrost zone where permafrost forms extensive elevated plateaus on abandoned floodplains. The region is extremely flat and vulnerable to eustatic sea-level rise and inland storm surges. These high-resolution permafrost maps support landscape change analyses and assessments of the impacts of climate change on permafrost in this region of high biological productivity, critical wildlife habitats, and subsistence-based human economy.

This dataset provides field observations of thaw depth and dominant vegetation types, a LiDAR-derived elevation map, and permafrost distribution and probability maps for an area on the coastal plain of the Yukon-Kuskokwim Delta (YKD), in western Alaska, USA. Field data were collected during July 8-17, 2016 to parameterize and to validate the derived permafrost maps. The YKD is in the sporadic to isolated permafrost zone where permafrost forms extensive elevated plateaus on abandoned floodplains. The region is extremely flat and vulnerable to eustatic sea-level rise and inland storm surges. These high-resolution permafrost maps support landscape change analyses and assessments of the impacts of climate change on permafrost in this region of high biological productivity, critical wildlife habitats, and subsistence-based human economy.

This dataset is comprised of one geo-referenced aerial image from the National Petroleum Reserve - Alaska (NPRA) on Alaska's Arctic Coastal Plain taken on 21 June 1955 by the U.S. Air Force and obtained from the Earth Resources Observation and Science (EROS) Center using the USGS EarthExplorer website in 2013. The image represents a historical snapshot of the landscape from that time.

This dataset is comprised of one geo-referenced aerial image from the National Petroleum Reserve - Alaska (NPRA) on Alaska's Arctic Coastal Plain taken on 21 June 1955 by the U.S. Air Force and obtained from the Earth Resources Observation and Science (EROS) Center using the USGS EarthExplorer website in 2013. The image represents a historical snapshot of the landscape from that time.

Geophysical measurements and related field data were collected by the U.S. Geological Survey (USGS) at the Alaska Peatland Experiment (APEX) site in Interior Alaska from 2018 to 2020 to characterize subsurface thermal and hydrologic conditions along a permafrost thaw gradient. The APEX site is managed by the Bonanza Creek LTER (Long Term Ecological Research). In April 2018, seven boreholes were emplaced to depths of 2.3-2.5 meters (m) to allow for repeat logging with downhole nuclear magnetic resonance (NMR) to quantify the spatial and temporal variations in unfrozen water content within active-layer and permafrost soils. NMR data were collected on ten separate occasions between April 2018 and October 2020. In June 2018, soil temperature and moisture sensors were installed at select locations and depths across the study site to record point-scale temperature and moisture conditions in 30 minute intervals. In August 2018, electrical resistivity tomography (ERT) data were collected along four 82 m-long transects. Models of electrical resistivity produced from these data revealed the spatial variability in soil lithology and thermal state (frozen vs. thawed) to depths up to 10-15 m below the surface. Lastly, manual permafrost-probe measurements of thaw depths were collected at each instrument location during summer site visits for comparison to the geophysical data.

This data set consists of a geo-referenced digital map and attribute data derived from the publication 'Permafrost map of Alaska'. The map is presented at a scale of 1 to 2,500,000 and shows the correlation of physiographic province to presence of permafrost across the state of Alaska. The digital data were prepared under the U.S. Geological Survey Global Change Program, Land Data Systems - Arctic Land Processes Studies for display and analysis of terrain. The line work was captured by hand digitizing the source map, Ferrians, O.J., 1965, Permafrost map of Alaska - U.S. Geological Survey Miscellaneous Geologic Investigations Map I-445. Scale 1 to 2,500,000. The digital map was assembled and edited in ARC/INFO. The source map projection is polyconic. It is based on the Clarke 1866 ellipsoid with a central meridian of 150 W longitude. The data were geo-referenced from digitizer coordinates to the polyconic projection and then projected into an Albers Equal Area projection. The coastline was taken from the U.S Geological Survey, 1 to 2,000,000 scale Digital Line Graph data (U.S. Geological Survey, 1987). Attributes for the permafrost map were assigned. Metadata documentation was completed in 1996. The map units are closed polygons that are generalized in shape and size. They are defined in terms of their physiographic characteristics and association with permafrost. Each unit differs with respect to all other units and is uniquely identified as follows. 11 Mountainous Area underlain by continuous permafrost 12 Mountainous Area underlain by discontinuous permafrost 13 Mountainous Area underlain by isolated masses of permafrost 21 Lowland and Upland Area underlain by thick permafrost 22 Lowland and Upland Area underlain by moderately thick to thin permafrost 23 Lowland and Upland Area underlain by discontinuous permafrost 24 Lowland and Upland Area underlain by numerous isolated masses of permafrost 25 Lowland and Upland Area underlain by isolated masses of permafrost 26 Lowland and Upland Area generally free of permafrost Use constraints - The U.S. Geological Survey should be acknowledged as the data source in products derived from these data. The data are general in nature and should not be used at a scale larger than 1 to 2,500,000, that of the original map. Users must assume responsibility to determine the usability of this data for their purposes. The use of these data is not restricted and may be interpreted by organizations, agencies, units of government or others; however, they are responsible for its appropriate application. Digital data files are periodically updated. Files are dated and users are responsible for obtaining the latest revisions of the data. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the agency regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. A copy of this map is presented on the CAPS Version 1.0 CD-ROM, June 1998.