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Arctic LTER Database

Arctic LTER Database

Conditions of Use

The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. Permission to use this dataset is granted to the Data User free of charge subject to the following terms:

1) Acceptable use. Use of the dataset will be restricted to academic, research, educational, government, recreational, or other not-for-profit professional purposes. The Data User is permitted to produce and distribute derived works from this dataset provided that they are released under the same license terms as those accompanying this Data Set. Any other uses for the Data Set or its derived products will require explicit permission from the dataset owner.
2 ) Redistribution. The data are provided for use by the Data User. The metadata and this license must accompany all copies made and be available to all users of this Data Set. The Data User will not redistribute the original Data Set beyond this collaboration sphere.
3 ) Citation. It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User will properly cite the Data Set in any publications or in the metadata of any derived data products that were produced using the Data Set. Citation should take the following general form: Creator, Year of Data Publication, Title of Dataset, Publisher, Dataset identifier. For example:

Shaver, G. 1989. Above ground biomass in acidic tussock tundra experimental site, 1989, Arctic LTER, Toolik, Alaska. Arctic LTER, Marine Biological Lab, Woods Hole, Ma 02543. 1989gsttbm 

4 ) Acknowledgement. The Data User should acknowledge any institutional support or specific funding awards referenced in the metadata accompanying this dataset in any publications where the Data Set contributed significantly to its content. Acknowledgements should identify the supporting party, the party that received the support, and any identifying information such as grant numbers. For example:

Data sets were provided by the Arctic LTER. This material is based upon work supported by the National Science Foundation under Grants #DEB-981022, 9211775, 8702328; #OPP-9911278, 9911681, 9732281, 9615411, 9615563, 9615942, 9615949, 9400722, 9415411, 9318529; #BSR 9019055, 8806635, 8507493.

5 ) Notification. The Data User will notify the Data Set Contact when any derivative work or publication based on or derived from the Data Set is distributed. The Data User will provide the data contact with two reprints of any publications resulting from use of the Data Set and will provide copies, or on-line access to, any derived digital products. Notification will include an explanation of how the Data Set was used to produce the derived work.
6 ) Collaboration. The Data Set has been released in the spirit of open scientific collaboration. Data Users are thus strongly encouraged to consider consultation, collaboration and/or co-authorship with the Data Set Creator.

By accepting this Data Set, the Data User agrees to abide by the terms of this agreement. The Data Owner shall have the right to terminate this agreement immediately by written notice upon the Data User's breach of, or non-compliance with, any of its terms. The Data User may be held responsible for any misuse that is caused or encouraged by the Data User's failure to abide by the terms of this agreement.


While substantial efforts are made to ensure the accuracy of data and documentation contained in this Data Set, complete accuracy of data and metadata cannot be guaranteed. All data and metadata are made available "as is". The Data User holds all parties involved in the production or distribution of the Data Set harmless for damages resulting from its use or interpretation.

Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data, Dataset via LTER Data Portal
Dataset ID:2009_UmiatCorrTK_ARCSSTK_points.02
Dataset Title:Inventory and description of thermokarst features observed along the Umiat Corridor in July 2009.
Investigator 1: 
First Name:Benjamin
Last Name:Crosby
Organization:Idaho State University
Address line 2:Department of Geosciences
Address line 3:921 South 8th Ave - Stop 8072
Zip Code:83209-8072
Investigator 2: 
First Name:Kacy
Last Name:Krieger
Organization:Idaho State University
Address line 2:Department of Geosciences
Address line 3:921 South 8th Ave - Stop 8072
Zip Code:83209-8072
Associate Investigators:
Keywords:thermokarst, inventory, gully thermokarst, active layer detachment, retrogressive thaw slump
Abstract:Using a combination of aerial imagery and ~1m resolution airborne lidar (collected July, 2009), we use manual visual inspection of the two datasets to identify point locations of over 7000 thermal erosion features (thermokarst) of varying maturity. For each feature we report its x,y position, the facing direction of the feature, the local topographic setting, the geologic unit it occurs on, the relative age of the feature and the specific type of thermal erosion feature.
For questions about the Metadata and data contact the Investigators.
For information about this web site contact:
Arctic LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7496
Online URL:
Data File URL
Data File Name 2009_UmiatCorrTK_ARCSSTK_points
Beginning Date 1/1/2010
End Date 1/1/2012
Number of Data Records 7124
Other Files to Reference
Availability Status Type 1
Quality Control Information Where possible, features were field confirmed.
Maintenance Description Version 2 renamed directory Jim L 13Dec13
Log of Changes:
Location Name Umiat Road Corridor  
Geographic Description North-northwest trending corridor of LiDAR data extending from the haul road near Toolik Lake to Umiat. Typically ~10.5km wide.  
Location Bounding Box    
West Bounding Coordinate -152.251  
East Bounding Coordinate -149.437  
North Bounding Coordinate 69.444  
South Bounding Coordinate 68.493  
OR if single point location    
Link to Google Map    
Organisms studied
Methods:Methods and Notes:

Data were collected by Master of Geology student Kacy Krieger during his work at Idaho State University. Features were observed visually typically using a slope map derived from the 1m DOT Umiat LiDAR DEM. Features were visually categorized for the local topographic setting, the relative age of the feature and the specific type of thermal erosion feature. Automated techniques were used to add the x,y position of each feature, the aspect and underlying geologic unit. All work was completed in ArcGIS v10.0 and data were organized within a geodatabase.

Description of variables:

XY Position:
All reported positions are based on the following projection system used by the LiDAR contractor for the Umiat project.

Authority: Custom

Projection: Transverse_Mercator
False_Easting: 1640419.947506561
False_Northing: 0.0
Central_Meridian: -150.0
Scale_Factor: 0.9999
Latitude_Of_Origin: 54.0
Linear Unit: Foot (0.3048)

Geographic Coordinate System: GCS_North_American_1983
Angular Unit: Degree (0.0174532925199433)
Prime Meridian: Greenwich (0.0)
Datum: D_North_American_1983
Spheroid: GRS_1980
Semimajor Axis: 6378137.0
Semiminor Axis: 6356752.314140356
Inverse Flattening: 298.257222101

This is the downslope direction (in degrees) that the feature faces. This was calculated as a derivative from the DEM and averaged using a neighborhood around the feature.

Topographic Setting:
This category was used to describe the setting of the feature to explore whether certain features occurred within or created a particular type of landform. The categories used were Conv (Convergent), Planar (no significant curvature) and Margin (feature is close to or on a break in slope, typically the edge of a river or lake).

Landform Age:
These categories and codes are consistent with the surficial geology map units described by Hamilton 1978 and 1979. They typically describe the glacial age of the landform but may simply describe the type of material present at or near the surface e.g. 'c' for undifferentiated colluvium. Note that some features are off Hamilton's maps and are thus not assigned an age. The full references for the publications are:

Hamilton, T. D. (1978). Surficial geologic map of the Philip Smith Mountains Quadrangle, Alaska. United States, U. S. Geological Survey: Reston, VA, United States.
Hamilton, T. D. (1979). Surficial geologic map of the Chandler Lake Quadrangle, Alaska. United States, U. S. Geological Survey : Reston, VA, United States.

Feature Maturity:
We classified each feature into one of three relative maturity classes: sharp (1), degrading (2), and diffuse (3) based on the condition of the head scarp, lateral walls, and depositional lobes. Sharp features have the steepest headwalls and best defined erosion and depositional zones. Degrading features have moderate relief on the headwall, a relaxed headwall slope and the change in boundary with the surrounding topography and headwall is diffused. Diffuse features have smooth, rounded headwall and depositional zones that make them difficult to distinguish from the surrounding topography.

Feature Type (or class):
We classified individual features based on morphology into three classes; active layer detachment, gully thermokarst and retrogressive thaw slumps (Jorgenson and Osterkamp, 2005; Jorgenson, 2008; Osterkamp et al., 2000). Active layer detachments (ALD) form when the active layer becomes saturated causing the active layer to slide or flow over the frozen substrate. These features are linear to curvilinear, narrow and generally much longer than wide. Retrogressive thaw slumps (RTS) form when exposed permafrost soils are exposed and experience rapid transport downslope resulting in a steep arc-shaped headwalls that retrogressively move upslope as thawed materials flow downslope and are deposited. Thermal erosion gullies or gully thermokarsts (GTK) form narrow, long channels along degraded ice wedges, bifurcated along those patterns and occur where surface water is concentrated.

Data Table

Variable Name Variable Description Data Type Units DateTime Format Code Information Missing Value Code
ObjectID unique ID assigned to each feature number number     -1111=Missing or Not Measured
Longitude Longitude in NAD_1983_Transverse_Mercator in FEET see Methods text        
Latitude Latitude in NAD_1983_Transverse_Mercator in FEET see methods text        
Aspect Downslope direction of the feature number degree     -1111=Missing or Not Measured
TopographicSetting Category of topographic position text        
Landform_Age Code describing the surficial geology text        
Feature_Maturity Categorical description of relative feature age number number     -1111=Missing or Not Measured
Feature_Type Categorical description of type of thermal erosion feature text        

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