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Data Set ID:
NSIDC-0500

Millennially Averaged Accumulation Rates for Lake Vostok, Version 1

This data set consists of inferred accumulation rates from three radar layers (26, 35 and 41 thousand years old) in the Vostok Subglacial Lake region. Accumulation rates were inferred using Local-Layer Approximation (LLA), which assumes that the strain-rate history of a particle traveling through the ice sheet can be approximated by the vertical strain-rate profile at the current position of the particle, which the researchers assume to be uniform. Parameters include location, in latitude and longitude, polar stereographic coordinates, and local grid X and Y coordinates, along with layer age, in thousands of years (ka), and inferred accumulation rate (cm/a). The data cover a 150 by 350 km area.

Data are available via FTP, as a text file (.txt) with columns in comma separated value format.

Geographic Coverage

Parameter(s):
  • Glaciers/Ice Sheets > Ablation Zones/Accumulation Zones
  • Glaciers/Ice Sheets > Ice Sheets
  • Radar
  • Snow/Ice
Spatial Coverage:
  • N: -75.7, S: -79.1, E: 80.5, W: 68.4

Spatial Resolution:
  • 1.5 km x 1.5 km
Temporal Coverage:
  • 29 September 2003 to 26 September 2012
Temporal Resolution: Not specified
Data Format(s):
  • ASCII Text
Platform(s) FIELD INVESTIGATION
Sensor(s): RADAR
Version: V1
Data Contributor(s): Joseph MacGregor, Kenichi Matsuoka, Michael Studinger, Edwin Waddington, Dale Winebrenner
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.

MacGregor, J. A., K. Matsuoka, M. S. Studinger, E. D. Waddington, and D. Winebrenner. 2011. Millennially Averaged Accumulation Rates for Lake Vostok, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5F769HV. [Date Accessed].

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Detailed Data Description

Format

Text file (.txt) with columns in comma separated value 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/nsidc0500_macgregor_V01/ directory. The data set consists of one data file, vostok_accum.txt.

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File Naming Convention

The data file, vostok_accum.txt , contains data on inferred accumulation rates for radar layers in the Lake Vostok region of Antarctica

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File Size

3.6 MB

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Volume

The data file is 3705 KB.

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Spatial Coverage

These data span a 150 km by 350 km area in the Lake Vostok region of Antarctica.

Southernmost Latitude: 79.1°S
Northernmost Latitude: 75.7°S
Westernmost Longitude: 68.4°E
Easternmost Longitude: 80.5°E

Spatial Resolution

1.5 km

Projection Description

Locations are provided in latitude/longitude, polar stereographic, as well as a local grid X, Y projection.

Grid Description

The local northing/easting grid was developed by M. Studinger specifically for the Lake Vostok region and is oriented along the long axis of the lake. The grid (229 points in local grid Y, 112 points in local grid X) is repeated three times here, once for each of the three layers (26.2, 34.8 and 41.0 ka) for which accumulation rates were inferred.

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Temporal Coverage

Radar data were collected during the Antarctic field season from 2000 to 2001. The radar layers span three time periods, approximately 26, 35 and 41 thousand years old.

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Parameter or Variable

Parameter Description

Table 1. Parameter Description
Parameter Description
Latitude Longitude in decimal degrees S
Longitude Latitude in decimal degrees W
Polar Sterographic X Polar stereographic X coordinates (km)
Polar Sterographic X Polar stereographic Y coordinates (km)
Grid X Local grid X (km)
Grid Y Local grid Y (km)
Layer Age Layer Age in thousands of years (ka)
Accumulation Rate Accumulation rate in centimeters per year (cm/a), inferred using local-layer approximation (LLA)

Sample Data Record

-79.072
104.86
1151
-305.47
-6
-6
26.2
NaN
-79.059
104.83
1152.5
-305.21
-6
-4.5
26.2
NaN
-79.047
104.8
1154
-304.95
-6
-3
26.2
NaN

Note. Not-a-number (NaN) values for accumulation rate occur when the layer was not traced in the vicinity of that particular grid point, and therefore was not interpolated onto it.

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Software and Tools

Data can be accessed using spreadsheet software.

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Data Acquisition and Processing

Data Source

60 MHz airborne ice-pentrating radar data were collected by the US Support Office for Aerogeophysical Research (SOAR) at the University of Texas Institute for Geophysics in 2000-2001.

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Derivation Techniques and Algorithms

The depths of radar-detected internal layers can be used to infer the spatial variability of accumulation rates. For this data set, researchers inferred accumulation rates from three radar layers, 26, 35 and 41 thousand years (ka) old, in the Vostok Subglacial Lake region using the LLA over a 150 km by 350 km area. The LLA assumes that the strain-rate history of a particle traveling through the ice sheet can be approximated by the vertical strain-rate profile at the current position of the particle, which is further assumed to be uniform. The LLA accumulation-rate map shows higher values in the northwestern corner of our study area and lower values near the downstream shoreline of the lake. The LLA-inferred accumulation-rate patterns over the three time periods are all similar, suggesting that the regional pattern did not change significantly between the start of the Holocene and the last ~20 ka of the last Glacial Period. For more details on methods, see MacGregor, et. al., 2009.

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References and Related Publications

Contacts and Acknowledgments

Dr. Joseph A. MacGregor
University of Texas at Austin
10100 Burnet Road, Bldg. 196
Austin, TX 78758
USA

Dr. Kenichi Matsuoka
Department of Earth and Space Sciences 
University of Washington 
Department of Earth and Space Sciences
Seattle, WA 98105
USA

Dr. Michael Studinger
Lamont-Doherty Earth Observatory
61 Route 9W
Palisades, NY 10964
USA

Dr. Edwin D. Waddington
University of Washington
Department of Earth and Space Sciences 
Box 351310 
Seattle, WA 98195-1310 
USA

Dr. Dale Winebrenner
University of Washington
Applied Physics Laboratory 
Gerberding Hall, Rm. 280
PO. Box 351
Seattle, WA 98195
USA 

Acknowledgments: 

This research was supported by the National Science Foundation (NSF) Office of Polar Programs (OPP) grant number 0538674.

Document Information

DOCUMENT CREATION DATE

5 August 2011

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