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Data Set ID:
NSIDC-0463

Ice Flow History of the Thwaites Glacier, West Antarctica, Version 1

This data set contains past flow lines of Thwaites Glacier. The flow lines were identified using layer patterns tracked between parallel radar layers, from a radar profile of the Thwaites Glacier catchment. The radar data was run and processed by the University of Texas Institute for Geophysics. The flow lines were identified from distinct layer patterns tracked between parallel radar layers.

Data are available via FTP in ASCII text (.txt) format.

Geographic Coverage

Parameter(s):
  • Glaciers/Ice Sheets > Glaciers
  • Glaciers/Ice Sheets > Glacier Topography/Ice Sheet Topography
  • Radar > Radar Cross-section
  • Radar > Radar Imagery
Spatial Coverage:
  • N: -76, S: -79.7, E: -99.5, W: -123

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 October 2004 to 1 March 2005
Temporal Resolution: Not specified
Data Format(s):
  • ASCII Text
Platform(s) FIELD INVESTIGATION
Sensor(s): ALTIMETERS, GRAVIMETERS, MAGNETOMETERS, RADAR, RADAR ECHO SOUNDERS
Version: V1
Data Contributor(s): Howard Conway, T. Fudge, Ginny Catania
Data Citation

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.

Conway, H., G. Catania, and T. J. Fudge. 2010. Ice Flow History of the Thwaites Glacier, West Antarctica, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5RR1W6X. [Date Accessed].

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Detailed Data Description

This data set contains past flow lines of Thwaites Glacier identified from distinct layer patterns tracked between parallel radar layers. Each row of data contains two pairs of x and y coordinates, which form one paleo flow line. Coordinates are in polar stereographic with units of km. The parallel of true scale is 71S.

Figure 1, adapted from Fudge et al. 2013, shows an InSAR velocity map (Joughin et al. 2009) overlain by radar lines (Holt et al. 2006). The purple lines indicate areas where radar-detected features were tracked. The yellow circles are shallow core locations from US-ITASE. The Red circle is the WAIS DIVIDE ice core site. Letters A through E are GPS locations.

InSAR velocity map
Figure 1. InSAR Velocity Map Overlain by Radar

Figure 2 displays radar-detected flow lines shown with black circles connected by thin black lines. X-Y coordinates for the paleo-flowlines are given in the file named paleo_flow-line_picks.txt. GPS velocities are shown with white arrows. InSAR velocities at GPS locations are shown with red arrows. Large black numbers are average direction diference (i) between radar-detected and InSAR ice flow directions. Small white numbers are direction difference between InSAR and GPS measurements. Small red numbers are direction difference between radar-detected and GPS. Background color is bedrock elevation.

Radar-detected Flow Lines
Figure 2. Radar-detected Flow Lines

Format

This data set consists of one data file in ASCII text (.txt) format.

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File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/conway_nsidc_0463/ directory. The data set consists of one file, paleo_flow_line_picks.txt, which contains flow line data derived from a radar sounding of Thwaites Glacier in West Antarctica.

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File Size

The data file is 13 KB.

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Spatial Coverage

The data were derived using radar sounding data collected from Thwaites Glacier in West Antarctica.

Southernmost Latitude: 79.7° S
Northernmost Latitude: 76° S
Westernmost Longitude: 99.5° W
Easternmost Longitude: 123° W

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Temporal Coverage

The radar data that support this investigation were collected by the University of Texas Institute for Geophysics during the Antarctic field season (October through February) in 2004 to 2005.

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Parameter or Variable

The data set contains a table of coordinates that define flow lines derived from a radar sounding of Thwaites Glacier in West Antarctica.

Parameter Description

Each row contains two pairs of x and y coordinates, which form one flow line. Coordinates are in polar stereographic with units of kilometers (km). The parallel of true scale is 71° S.

Sample Data Record

x1 y1 x2 y2
-1.3438309e+003 -5.8595677e+002 -1.3461408e+003 -5.7038227e+002
-1.3388820e+003 -5.8459680e+002 -1.3409560e+003 -5.6897531e+002
-1.3364551e+003 -5.8392782e+002 -1.3391090e+003 -5.6846833e+002
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Software and Tools

Software and Tools

Data are accessible using spreadsheet software.

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Data Acquisition and Processing

Theory of Measurements

Researchers identified past glacial flow lines for Thwaites Glacier in Antarctica using internal layer patterns detected with radar. The patterns in the internal layers of glaciers were created upstream, and over time moved downstream. By looking at the pattern between radar lines, researchers can discern the direction and timescale of past flow. The technique is described in more detail in Ng and Conway, 2004.

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References and Related Publications

Contacts and Acknowledgments

Dr. Howard Conway
Department of Earth and Space Sciences 
University of Washington 
Johnson Hall Rm-070, Box 351310 
4000 15th Avenue NE 
Seattle, WA 98195
USA

Dr. Ginny Catania
University of Texas Institute of Geophysics 
J.J. Pickle Research Campus, Bldg. 196
10100 Burnet Road (R2200)
Austin, TX 78758
USA

T. J. Fudge
Department of Earth and Space Sciences 
University of Washington
Johnson Hall
4000 15th Avenue NE 
Seattle, WA 98195
USA

Acknowledgments: 

This research was supported by NSF OPP grant 0739372.

Document Information

DOCUMENT CREATION DATE

28 April 2010

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