Documentation for Ice Thickness and Internal Layer Depth Along the 2001 and 2002 US ITASE Traverses, Version 1

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Detailed Data Description


Four ASCII text files contain the data. Each file has columns for longitude and latitude in decimal degrees, ice thickness in meters, and depth to the prominent internal layer in meters. Data spacing along the traverse is approximately 12 m. For each year of the traverse (2001 and 2002), an "info_table.txt" table indicates where the core sites were located along the route as well as any turns (kinks) in the traverse.

Corresonding JPEG image files show graphical plots of the data. Each year of the traverse also has a small "data_sample.jpg" image of radar data and two "map.jpg" files showing maps of the routes each year.

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File Naming Convention

ASCII files:

JPEG files:

File sizes range from 1 KB to 4 MB.

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Spatial Coverage

The traverses fall within the following bounding coordinates:

Southernmost Latitude: 90°S
Northernmost Latitude: 80°S
Westernmost Longitude: 120°W
Easternmost Longitude: 76°W

Spatial Coverage Map

Map: Location of US ITASE traverses

Map: Location of US ITASE traverses

Above is a map of the 1999-2002 traverse routes for the U.S. portion of the International Transantarctic Scientific Expedition (US ITASE).

Spatial Resolution

Data spacing along the traverse is approximately 12 m. Surface elevations along the traverse are available from a companion data set by Hamilton et al. at U. of Maine.

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Temporal Coverage

Data were collected from 01 November 2001 to 10 January 2003.

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Parameter or Variable

Unit of Measurement

Data files contain ice thickness and depth to the prominent internal layer in meters. Thickness and depth data are accurate to ± 10 m, and position values are accurate to within 1 m.

Sample Data Record

The following sample shows the first several lines of "jacobel_usitase_2001_01-6_ellsworth.txt."

Latitude Longitude Distance-kilometers 17.5ka bed_depth
-76.1011 -89.0138 0 -9999 2131.305
-76.1012 -89.0138 0.010691 -9999 2125.425
-76.1014 -89.0137 0.026805 -9999 2125.425
-76.1014 -89.0137 0.035792 -9999 2127.945
-76.1015 -89.0136 0.046494 -9999 2125.425
-76.1016 -89.0136 0.057361 -9999 2125.425
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Software and Tools

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Data Acquisition and Processing

Data Acquisition Methods

A ground-based impulse radar was used to sound the ice. Approximately 1,500 traces were averaged (stacked) for each waveform and recorded at approximately 12 m intervals. Positions were acquired with a dual-frequency precision Global Positioning System (GPS) using kinematic survey mode and differential correction.

A bright, reflective layer from volcanic activity dated 17,500 years ago is visible in all of the major cores (Byrd, Siple, etc.)

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Sensor or Instrument Description

Data were collected with a ground-based impulse radar with a center frequency of approximately 3 MHz.

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References and Related Publications

Contacts and Acknowledgments

Robert Jacobel and Brian Welch
St. Olaf College
Department of Physics
Northfield, MN 55057 USA


This research was supported by NSF OPP award #9814574, "Radar Studies of Internal Stratigraphy and Bedrock Topography Along the US ITASE Traverse."

Document Information


March 2005