Glaciological Investigations of the Bulge and Trunk of Kamb Ice Stream, West Antarctica

Summary

This data set contains radar data from the Kamb Ice Stream (KIS), formerly known as Ice Stream C, in West Antarctica. The project was part of a larger study to assess the likelihood of ice stream reactivation. Parameters include latitude, longitude, distance along profile, ice thickness pick, bright layer depth, and surface elevation, from approximately 1600 km of ground-based radar traverses recorded during the 2004 and 2005 Antarctic field seasons.

Data are available via FTP as ASCII text files (.txt). Profile location maps and sample profile sections are available as Joint Photographic Experts Group (.jpg) image files. The data are also available as binary data on DVD, upon request.

Citing These Data

The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.

The following example shows how to cite the use of this data set in a publication. List the principal investigators, year of data set release, data set title and version number, publisher: NSIDC, and digital media.

Jacobel, R. 2009. Glaciological Investigations of the Bulge and the Trunk of Kamb Ice Stream, West Antarctica. Boulder, Colorado, USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5ZC80SH.

Overview Table

Category	Description
Data format	ACSII text files (.txt), Joint Photographic Experts Group (.jpg) image files, binary data (available via DVD, on request)
Spatial coverage and resolution	Southernmost Latitude: 83°S Northernmost Latitude: 82°S Westernmost Longitude: 140°W Easternmost Longitude: 130°W
Temporal coverage and resolution	Two Antarctic field seasons (Nov-Dec) in 2004 and 2005
File naming convention	A_line_2004_sample_profile.jpg A_line.txt LAKE_SIPLE_1.txt KIS_2005_profile_location_map.jpg
File size	Files in this data set range in size from 12 KB to 375 KB
Parameter(s)	Latitude and longitude Distance along profile Ice thickness pick Bright layer depth Surface elevation
Procedures for obtaining data	Data are available via FTP.

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts and Acknowledgments

Investigator(s)

Dr. Robert Jacobel
St. Olaf College
Environmental Studies Program
St. Olaf College
1520 St. Olaf Ave.
Northfield, MN 55057

Technical Contact

Acknowledgements

This research was supported by NSF OPP grant 0337567.

2. Detailed Data Description

Format

Data are available as ASCII text files (.txt). Example profiles and location maps are available as image files (.jpg). The data are also available as binary data on DVD, upon request.

File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/jacobel_nsidc_0380/ directory. Within this directory, there are two subdirectories separated by the year of observation, 2004 and 2005. The directory also contains a readme file in both ASCII text format and Microsoft Word format. To request the data set as binary data, please contact NSIDC User Services.

Each data folder contains data files for each profile segment, a .jpg map file showing profile segment locations and one .jpg radar profile showing a z-scope example of the raw data.

File Naming Convention

Files are named according to the following convention:

XXX-line.txt

• Where: XXX corresponds to the profile identified in the location maps. The specific location (latitude and longitude) of each profile is described in its corresponding data file.

File Size

Files in this data set range in size from 12 KB to 375 KB.

Spatial Coverage

Data were collected on the Kamb Ice Stream in West Antarctica.

Southernmost Latitude: 83°S
Northernmost Latitude: 82°S
Westernmost Longitude: 140°W
Easternmost Longitude: 130°W

Spatial Coverage Maps

2004 Location Map

2005 Location Map

 

Temporal Coverage

Data in this collection were obtained during two Antarctic field seasons (Nov-Dec) in 2004 and 2005.

Parameter or Variable

 

Table 1. Parameters in the Profile Data Files

Parameter	Description
Latitude/Longitude	Location of radar measurement
Distance	Distance along profile (km)
Bed Depth	Ice sheet depth, or thickness (m)
Layer Depth	Depth (m) of bright layer, which corresponds to a volcanic eruption about 17,500 YBP based on dating from the Byrd Ice Core. For more information see Jacobel and Welch, 2005.
Elevation	Surface elevation (m)

 

Sample Data Record

The following example shows sample data from the LakeA7_camp.txt file in the 2004 folder.

Latitude	Longitude	Distance	Bed Depth	Layer Depth	Elevation
-82.05	-131.8962	0.009	1364.67	5 748.67	649.2322

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

The total volume of the data set is less than 3 MB.

Software and Tools

Data are accessible using standard spreadsheet software.

Related Data Collections

• Antarctic Glaciological Data Center (AGDC)

4. Data Acquisition and Processing

Theory of Measurements

Researchers conducted ground-based ice-penetrating radar surveys on the Kamb Ice Stream to detect regions of wet and dry bed conditions based on differences in the radar reflectivity, as part of a larger study to assess the likelihood of ice stream reactivation.

Sensor or Instrument Description

Researchers used a 3 MHz radio echo-sounding system to transmit and receive radio waves through as much as three kilometers of ice. For more information, visit the St. Olaf College Radar Program Web site.

Data Acquisition Methods

The system and operator were towed by a snow machine. The receiver and operator were housed in a small shelter built on a wooden Komatik sled. Power for the receiver, and for battery chargers, was provided either by a solar-powered battery system, or a small gas-powered generator mounted on the back of the sled. The transmitter batteries were recharged by the solar panels or generator. The shelter was also equipped with a GPS receiver to locate the data points.

The transmitter was towed 100 m or more behind the receiver sled. The transmitter and its battery sat in a small sled, protected from the elements by the sled's nylon cover. The antennas for the transmitter and receiver were housed in strong rubber hoses and tied to the tow ropes to keep the antennas as straight and parallel as possible.

 

5. References and Related Publications

Jacobel, R. W., A. M. Gades, D. L. Gottschling, S. M. Hodge and D. L. Wright. 1993. Interpretation of radar-detected internal layer folding in West Antarctic ice streams. Journal of Glaciology, 39(133), 528–537.

Jacobel, R. W., T. A. Scambos, C. F. Raymond and A. M. Gades. 1996. Changes in the configuration of ice stream flow from the West Antarctic Ice Sheet. Journal of Geophysical Research, 101(B3), 5499–5504.

Jacobel, R. W., T. A. Scambos, N. A. Nereson and C.F. Raymond. 2000. Changes in the margin of Ice Stream C, Antarctica. Journal of Glaciology, 46(152), 102–110

Jacobel, R. W. , B. C. Welch, D.J. Osterhouse, R. Pettersson and J.A. MacGregor. 2007. Spatial Variation of Basal Conditions on Kamb Ice Stream. EOS Transactions American Geophysical Union, 88(52). C54A-03.

Jacobel, R. W., B. C. Welch. 2005. A time marker at 17.5 kyr BP detected throughout West Antarctica. Annals of Glaciology, 41. 47-51.

The following related documents are available on NSIDC's Web site.

Table 2. Related Documents

Document	Description	URL
Antarctic Glaciological Data Center (AGDC)	Product Web site	http://nsidc.org/agdc/
St. Olaf College Center for Geophysical Studies of Ice and Climate	Investigator program Web site	http://www.stolaf.edu/other/cegsic/

6. Document Information

Acronyms

The following acronyms are used in this document.

Table 3. Acronyms and Abbreviations

Acronym	Description
FTP	File Transfer Protocol
KIS	Kamb Ice Stream
NSIDC	National Snow and Ice Data Center
URL	Uniform Resource Locator

Document Creation Date

23 March 2009

Document URL

http://nsidc.org/data/docs/agdc/nsidc0380_jacobel/index.html