EFB8C1C7-F41A-44DD-9673-87CADDE645EE eng utf8 dataset dataset EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development - Center for Public Health and Environmental Assessment (CPHEA), EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas pointOfContact 2025-06-26 ISO 19139 Geographic Information - Metadata - Implementation Specification 2007 2 column 74332 30.000000 row 61832 30.000000 area true false -738287.982393 517928.530828 -738287.982393 2372888.530828 1491672.017607 2372888.530828 1491672.017607 517928.530828 376692.017607 1445408.530828 center 4326 EPSG EnviroAtlas - Probabilistic Estimates of the Distribution of Near-surface (within 1m) Permafrost in Alaska 2015-10-16 creation 2025-05-28 publication U.S. Environmental Protection Agency (US EPA) originator U.S. EPA Office of Research and Development (ORD) - Center for Public Health and Environmental Assessment (CPHEA) Research Triangle Park, NC publisher mapDigital 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 This EnviroAtlas-hosted layer is a gridded product from previously released USGS-funded research (Pastick et al., 2015). The overall goal of EnviroAtlas is to employ and develop the best available science to map indicators of ecosystem services production, demand, and drivers for the nation. This dataset was created by: 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 The original dataset is available on the USGS ScienceBase-Catalog here: https://www.sciencebase.gov/catalog/item/5602ab5ae4b03bc34f5448b4. completed EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development - Center for Public Health and Environmental Assessment (CPHEA), EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas publisher asNeeded Alaska United States place EPA Place Names 2015-01-31 publication Biology Cleanup Climate Conservation Contaminant Drinking Water Ecosystem Emergency Energy Environment Exposure Facilities Ground Water Hazards Impact Indicator Land Management Modeling Natural Resources Permits Remediation Response Risk Sites Spills Surface Water Toxics Transportation Waste Water theme EPA GIS Keyword Thesaurus 2007-11-02 publication 020:072 theme Federal Program Inventory 2013-09-16 publication Ecosystem Services EnviroAtlas Environment Environmental Atlas Habitat Imperiled Land Cover Protected Lands Society Soils Threatened Utilities theme User 2022-01-11 publication None. Please check sources, scale, accuracy, currency and other available information. Please confirm that you are using the most recent copy of both data and metadata. Acknowledgement of the EPA would be appreciated. EPA Public Domain License licenseUnrestricted https://edg.epa.gov/EPA_Data_License.html unclassified https://project-open-data.github.io/schema/#accessLevel grid eng utf8 Microsoft Windows 10 Version 10.0 (Build 22631) ; Esri ArcGIS 13.3.0.52636 true -173.579902 -117.451576 52.404332 71.355013 2001-01-01T00:00:00 2010-01-01T00:00:00 Permafrost Probability within 1m image 1 1 Band_1 100 0 Unified Code of Units of Measure [arb'U] false false false false false Raster Dataset https://enviroatlas.epa.gov/download/Permafrost_AK.zip download download https://enviroatlas.epa.gov/arcgis/rest/services/Rasters/Permafrost_Probability_Near_the_Surface/ImageServer ESRI:ArcGIS offlineAccess https://www.epa.gov/enviroatlas/enviroatlas-data information information https://www.epa.gov/enviroatlas information information dataset Tests for integrity have not been performed. EPA National Geospatial Data Policy Features have been reviewed by U.S. EPA EnviroAtlas Project Managers for public release. true Features represented have not been tested for completeness EPA National Geospatial Data Policy Features have been reviewed by U.S. EPA EnviroAtlas Project Managers for public release. true Dataset originated from USGS, available online on USGS ScienceBase Catalog 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 "NoData" to produce a dataset with likelihood values ranging from 0 to 100 only. To create a logical range of probability from 0 to 100 . EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development - Center for Public Health and Environmental Assessment (CPHEA), EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas pointOfContact Description of process from USGS researchers in data documentation: "Decision-tree models were developed to predict the presence-absence and probability of near-surface (within 1 m) permafrost distribution. Users of this product are referred to Pastick et al., (2015) for additional information on processing techniques used in this study. Select land cover types (i.e. open water, perennial ice/snow, developed, barren, cultivated), as defined by 2001 NLCD data, were masked using ERDAS IMAGINE 2011 model maker." USGS researchers performed the above process to predict permafrost using NLCD land cover data. For further details on their methods refer to their paper (Pastick et al., 2015). Online Resource: https://www.sciencebase.gov/catalog/item/5602ab5ae4b03bc34f5448b4 Probabilistic Estimates of the Distribution of Near-surface (within 1m) Permafrost in Alaska 2015-10-16 publication asNeeded 2025-07-30