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EnviroAtlas - Probabilistic Estimates of the Distribution of Near-surface (within 1m) Permafrost in Alaska
This dataset was created by USGS and is being hosted by US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets). The original raster dataset has additional categories to differentiate between permafrost probability areas and other land cover categories. In the USGS raster, values range from 0 to 105, with values above 100 representing the following: 101 = open water; 102 = perennial ice/snow; 103 = developed; 104 = barren, and; 105 = cultivated areas. These values has been modified by the EnviroAtlas team to change values above 100 to "-1" to produce a dataset with modeled likelihood values ranging from 0 to 100 only. Abstract: Pastick et al., 2015 : "This medium resolution (i.e. 30-m pixels) spatial dataset provides an estimate of the occurrence of near-surface (within 1 m of the ground surface) permafrost in Alaska. The dataset was developed using a decision-tree model that statistically and spatially extended late-season field observations (n ~ 17,000) using remotely sensed imagery, climatic data, and thematic maps of a wide range of surface and subsurface biophysical characteristics. To circumvent the use of seasonal frost observations, only thaw-depth measurements taken during late-season months (late July to mid-September) or measurements designated to have no near-surface (within 1m) permafrost were used for model calibration and validation. Individual pixel values represent the probability of encountering near-surface permafrost (i.e. 0 to 100 %), as derived from a tree ensemble model, and pixel values greater than 100 correspond to masked land cover types (i.e. 101 = open water; 102 = perennial ice/snow; 103 = developed; 104 = barren, and; 105 = cultivated areas) as defined by the 2001 National Land Cover Database. Decision tree models and resultant maps were tested using independent field observations and f-fold cross validations, which indicated that the map product has an overall accuracy of approximately 85 % when using a probability threshold of 50 % (i.e. less than 50 % = near-surface permafrost absent; greater than or equal to 50 % = near-surface permafrost present)" Pastick, N. J., Jorgenson, M. T., Wylie, B. K., Nield, S. J., Johnson, K. D., & Finley, A. O. (2015). Distribution of near-surface permafrost in Alaska: Estimates of present and future conditions. Remote Sensing of Environment, 168, 301-315. https://doi.org/10.1016/j.rse.2015.07.019
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Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, ERT Data Inversions
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site, surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe the associated ERT inversions.
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, ERT Data Inversions
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site, surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe the associated ERT inversions.
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, Survey Information
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site, surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe the timing, location, and array types associated with the ERT surveys.
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, Survey Information
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site, surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe the timing, location, and array types associated with the ERT surveys.
Probabilistic estimates of the distribution of near-surface (within 1m) permafrost in Alaska.
공공데이터포털
This medium resolution (i.e. 30-m pixels) spatial dataset provides an estimate of the occurrence of near-surface (within 1 m of the ground surface) permafrost in Alaska. The dataset was developed using a decision-tree model that statistically and spatially extended late-season field observations (n ~ 17,000) using remotely sensed imagery, climatic data, and thematic maps of a wide range of surface and subsurface biophysical characteristics. To circumvent the use of seasonal frost observations, only thaw-depth measurements taken during late-season months (late July to mid-September) or measurements designated to have no near-surface (within 1m) permafrost were used for model calibration and validation. Individual pixel values represent the probability of encountering near-surface permafrost (i.e. 0 to 100 %), as derived from a tree ensemble model, and pixel values greater than 100 correspond to masked land cover types (i.e. 101 = open water; 102 = perennial ice/snow; 103 = developed; 104 = barren, and; 105 = cultivated areas) as defined by the 2001 National Land Cover Database. Decision tree models and resultant maps were tested using independent field observations and f-fold cross validations, which indicated that the map product has an overall accuracy of approximately 85 % when using a probability threshold of 50 % (i.e. less than 50 % = near-surface permafrost absent; greater than or equal to 50 % = near-surface permafrost present).
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, ERT Data
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site,surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe the ERT data.
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, ERT Data
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site,surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe the ERT data.
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, ERT Data
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site,surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe the ERT data.
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, Field Data
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site, surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe field data and active layer depth associated with ERT surveys.
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014, Field Data
공공데이터포털
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site, surveys were performed across a thermokarst bog area bordered by spruce forest and forested permafrost plateau. Some surveys partly overlap in coverage within a season, and some surveys were repeated between seasons. Different electrode array types, including dipole-dipole, extended dipole-dipole, and Wenner-Schlumberger, were compared at some sites. The metadata here specifically describe field data and active layer depth associated with ERT surveys.
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