Scientists
Research Grants
Scientific Publications
Informatics Research
NSIDC Scientific ExpeditionsOn Thin Ice:
Expedition to a Crumbling Ice Shelf
Scientists blog from Antarctica and provide a glimpse of what it's like to do research in the field. Read their blog ...
Current Conditions
Icelights: Answers to your burning questions about ice and climate
What's hot in the news around climate and sea ice and what are scientists talking about now? Read more...
What is the Cryosphere?
When scientists talk about the cryosphere, they mean the places on Earth where water is in its solid form, frozen into ice or snow. Read more ...
This data set, part of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, provides Greenland outlet glacier terminus positions created from MEaSUREs Synthetic Aperture Radar (SAR) mosaics and Landsat 8 OLI imagery.
See Greenland Ice Mapping Project (GIMP) for related data.
This is the most recent version of these data.
Initial release
STANDARD Level of Service
Data: Data integrity and usability verified
Documentation: Key metadata and user guide available
User Support: Assistance with data access and usage; guidance on use of data in tools
|
Geographic Coverage |
Once you have logged in, you will be able to click and download files via a Web browser. There are also options for downloading via a command line or client. For more detailed instructions, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login. Earthdata Search: This application allows you to search, visualize, and access data across thousands of Earth science data sets. Additional customization services are available for select data sets, including subsetting, reformatting, and reprojection. |
As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.
Joughin, I., T. Moon, J. Joughin, and T. Black. 2015, 2017. MEaSUREs Annual Greenland Outlet Glacier Terminus Positions from SAR Mosaics, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/DC0MLBOCL3EL. [Date Accessed].As a condition of using these data, we request that you acknowledge the author(s) of this data set by referencing the following peer-reviewed publication.
Moon, T. and I. Joughin. 2008. Changes in ice front position on Greenland's outlet glaciers from 1992 to 2007, Journal of Geophysical Research-Earth Surface. 113. Art. #F02022. https://doi.org/10.1029/2007JF000927
ESRI ArcGIS Shapefile
.shp – main file that stores the feature geometry.shx – index file that stores the index of the feature geometry.dbf – dBASE table that stores the attribute information of features.sbn and .sbx – files that store the spatial index of the features.prj – file that stores the coordinate system information.cpg – optional file to specify the code page for identifying the character set to be used
There is also a metadata file (.xml) for each shapefile.
Data are available on the HTTPS site in https://n5eil01u.ecs.nsidc.org/MEASURES/NSIDC-0642.001/.
Within this directory are the following folders:
| Folder Name | Description |
|---|---|
| 2000.09.30 | Winter 2000–2001 glacier terminus position data and glacier IDs |
| 2005.12.24 | Winter 2005–2006 glacier terminus position data |
| 2006.12.30 | Winter 2006–2007 glacier terminus position data |
| 2007.11.22 | Winter 2007–2008 glacier terminus position data |
| 2009.01.04 | Winter 2008–2009 glacier terminus position data |
| 2013.01.15 | Winter 2012–2013 glacier terminus position data |
| 2015.01.21 | Winter 2014–2015 glacier terminus position data |
| 2016.02.02 | Winter 2015–2016 glacier terminus position data |
| 2017.02.01 | Winter 2016–2017 glacier terminus position data |
The 2000.09.30 folder contains 18 files: 9 files for the glacier identifiers and 9 for the terminus position data. All other folders contain 9 files each for the terminus position data.
This section explains the shapefile file naming convention for this data set.
Example File Names:
termini_0809_v01.2.cpgtermini_0809_v01.2.dbftermini_0809_v01.2.prjtermini_0809_v01.2.sbntermini_0809_v01.2.sbxtermini_0809_v01.2.shptermini_0809_v01.2.shxtermini_0809_v01.2.xml
Convention:
termini_XXYY_v01.2.extGlacierIDs.ext
| String | Description |
|---|---|
termini |
Glacier terminus position file |
GlacierIDs |
GlacierID denotes a reference file with glacier points and consistent glacier identification number. |
XXYY |
Winter season. For example, 0809 is the winter of 2008–2009. |
vxx.x |
Current version number |
EXT |
File extension. The shapefile (.shp) format includes: .cpg (character set code), .dbf (attributes), .prj (projection information), .sbn and .sbx (spatial index), .shx (feature geometry index), and .xml (metadata). |
Character set code (.cpg), spatial index (.sbx), and projection (.prj) files average 1 KB.
Spatial index files (.sbn) range from 2 KB to 3 KB.
Feature geometry index files (.shx) average approximately 2 KB.
Database files (.dbf) range from 25 to 68 KB.
Shapefiles (.shp) range from 6 KB to 100 KB.
Metadata files (.xml) average approximately 7 KB.
The complete data volume is approximately 1153 KB.
Southernmost Latitude: 60° N
Northernmost Latitude: 83° N
Westernmost Longitude: 75° W
Easternmost Longitude: 14° W
The nominal uncertainty in digitized position is 50 m, but could be larger in regions where there is poor contrast at the terminus (e.g., melange). Nominal ground resolution for the source SAR mosaics and Landsat ranges between 15 m to 50 m.
GeoTIFFs are provided in a WGS 84 polar stereographic grid with a standard latitude of 70° N and rotation angle of -45° (sometimes specified as a longitude of 45° W). With this convention, the y-axis extends south from the North Pole along the 45° W meridian (EPSG:3413).
Data are available for the following winters.
Table 3 lists the exact date ranges for each winter.
| Data Year | Date Range |
|---|---|
| 2000/01 | 30 Sept 2000 – 23 Jan 2001 |
| 2005/06 | 24 Dec 2005 – 04 Apr 2006 |
| 2006/07 | 30 Dec 2006 – 04 Feb 2007 |
| 2007/08 | 22 Nov 2007 – 30 Mar 2008 |
| 2008/09 | 10 Jan 2009 – 05 Feb 2009 |
| 2012/13 | 15 Jan 2013 – 26 Mar 2013 |
| 2014/15 | 21 Jan 2015 – 31 Mar 2015 |
| 2015/16 | 02 Feb 2016 – 02 Apr 2016 |
| 2016/17 | 01 Feb 2017 – 06 Apr 2017 |
One set of ice front positions per year.
Geometric ice front positions.
Shapefiles of ice front locations for outlet glaciers in Greenland for 2000–01, 2005–06, 2006–07, 2007–08, 2008–09, 2012–13, 2014-15, 2015-16, and 2016-17 winter seasons. Beginning with the 2014-15 season, three new fields are included in the data. See Table 4 for a description of all data fields.
| Data Field | Description | Values |
|---|---|---|
| GlacierID | Numerical ID assigned to each glacier (used consistently across all data sets) |
|
| QualFlag (included beginning with 2014 data) |
Quality flag indicator for digitized ice fronts of lower certainty or drawing from multiple image sources |
|
| ImgSource (included beginning with 2014 data) |
Satellite source of image used to digitize terminus position |
|
| DateRange (pre-2014 data) |
Date range for images from full Greenland mosaic used to create digitized ice fronts | DDMMMYYYY - DDMMMYYYY |
| DATE (change to new format begins with 2014 data) |
Date of image used to digitize terminus position | YYYYMMDD |
| GrnlndcNam (updated* beginning with 2014 data and in GlacierIDv01.1.shp) |
Greenlandic glacier name | *Values are standardized to match "New Greenlandic" attribute in database of Greenland glacier names (Bjørk et al., 2015) |
| Official_n (included beginning with 2014 data and in GlacierIDv01.1.shp) |
Officially recognized glacier name | Values are standardized to match "Official_n" attribute in database of Greenland glacier names (Bjørk et al., 2015) |
| GlacName (pre-2014 data) | Glacier Name | Glacier name (usually European glacier name) |
| AltName (included beginning with 2014 data and in GlacierIDv01.1.shp) |
Alternative glacier name | Includes foreign name or Old Greenlandic name (Bjørk et al., 2015), or other recognized names |
Figure 1 illustrates ice front positions for three Greenland glaciers during six winters.
From 2000 through 2013, the terminus positions were created using 20 m resolution SAR Mosaics of Greenland. As of 2014, the positions were created using the SAR imagery from the Copernicus Sentinel-1 satellite and Landsat 8 panchromatic imagery.
See MEaSUREs Greenland Ice Sheet Mosaics from SAR Data and MEaSUREs Greenland Image Mosaics from Sentinel-1A and -1B, Version 2 for information on the base maps used to create this data set.
Terminus positions were digitized using mosaics created from RADARSAT satellite data through 2013, and as of 2014, they were created from Sentinel-1 and Landsat 8 satellite data. Positions were digitized for Greenland Ice Sheet outlet glaciers with terminus widths of roughly 1.5 km or greater. All glaciers that appear in each year's mosaic were digitized with few exceptions. For users of the data set, image quality varies and should be considered on a per-glacier basis. In cases where the terminus was highly fractured, the terminus position does not include fully detached (fractured) areas. For some glaciers, this determination is not clearly objective.
Number of glaciers in full data set: 238
Not all glaciers appear in each year due to limits in the satellite coverage; however, as of the 2014/15 winter season, all glaciers are included.
| Data Year | Number of glaciers digitized |
|---|---|
| 2000/01 | 205 |
| 2005/06 | 203 |
| 2006/07 | 200 |
| 2007/08 | 208 |
| 2008/09 | 201 |
| 2012/13 | 206 |
| 2014/15 | 238 |
| 2015/16 | 238 |
| 2016/17 | 238 |
Errors in digitized terminus location may occur due to:
The digitization line is meant to cover roughly the full width of the active glacier terminus and the line ends do not necessarily indicate a junction between ice and rock or any other defined measure of a glacier edge. Therefore, this data set should not be used as a measure of glacier width.
For information about the SAR systems used to construct the mosaics from which this data set is derived, see the Alaska Satellite Facility's SAR Basics web page, the Japan Aerospace Exploration Agency (JAXA) About ALOS - PALSAR site, and the European Space Agency's Copernicus Sentinel-1 site. Information on the Landsat-8 OLI sensor is available on the USGS web site.
Version 1.2 was released in October 2017. Refer to Table 6 for this data set's version history:
| Version | Description |
|---|---|
| V1.2 (October 2017) | Added glaciers to two winters: 2006/2007 -- glaciers 90 and 91 2008/2009 -- glaciers 1-9, 90, and 91 |
| V1.1 (August 2017) | Minor changes include:
|
| V1 (September 2015) | Initial release |
Ian Joughin
University of Washington
Applied Physics Laboratory
1013 NE 40th Street
Box 355640
Seattle, WA 98105
Twila Moon
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449 USA
Jonah Joughin
Jonahjoughin@gmail.com
Taryn Black
teblack@uw.edu
These data were generated through a grant from the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Program. Digitized ice fronts were created by Dr. Twila Moon. Contains modified Copernicus Sentinel data (2014-2017), acquired by the European Space Agency, distributed through the Alaska Satellite Facility, and processed by Joughin, I., T. Moon, J. Joughin, and T. Black.
29 September 2015
October 2017
Home | Contact Us
© 2020, National Snow and Ice Data Center :: Advancing knowledge of Earth's frozen regions
