Roosevelt Island Bedrock and Surface Elevations


This data set consists of bedrock and surface elevation readings taken by ground penetrating radar (GPR) and Global Positioning System (GPS) on Roosevelt Island, an ice dome within the Ross Ice Shelf. Locations were validated by GPS readings of poles set in the surface snow. The data was collected between November and December, 1997.

Data are available via ftp, and are provided in a text file with an accompanying file that provides GPS locations. Surface and bedrock elevations are given in meters above WGS84.

Citing These Data:

Conway, H. 1998. Roosevelt Island Bedrock and Surface Elevations. Boulder, CO: National Snow and Ice Data Center.

Overview Table

Category Description
Data format Text files
Spatial coverage and resolution Roosevelt Island on the Ross Ice Shelf
Temporal coverage and resolution November and December, 1997
Tools for accessing data No special tools required
File naming convention Data file is named checks.txt. The file listing all the pole locations is named risdgps.txt.
File size 15 Kb, combined
Parameter(s) surface elevation, bedrock 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) Name and Title:

Howard Conway, Research Professor, University of Washington

Technical Contact:

NSIDC User Services
National Snow and Ice Data Center
University of Colorado
Boulder, CO 80309-0449  USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services

2. Detailed Data Description:


Data are available in a text file. There is also a file containing data for elevation profiles.

File Size:

The checks.txt file is 2 Kb. The pole location file (risdgps.txt) is 13 Kb.

Spatial Coverage:

Southernmost_Latitude: 79.5906 S
Northernmost_Latitude: 79.4480 S
Westernmost_Longitude: 161.5307 W
Easternmost_Longitude: 159.8077 W

Temporal Coverage:

Data were collected during November and December, 1997.

Parameter or Variable:

Parameter Description:

Bed and surface elevations were measured at 15 locations.
Profiles in the experiment refer to the traverses the investigator made across the island.

Unit of Measurement:

Bed and surface elevation are measured in meters above WGS84. (WGS 84 is an earth fixed global reference frame. For more information, see

Sample Data Record:

AW208 ATline 79.4839 161.0559 -230 488.8
AW208 Aline 79.4838 161.0554 -236 488.8
A00 Aline 79.3539 160.3233 -276 222.4

Data Access:

Data are available via FTP.


Data are available at no cost.

Software and Tools:

Most browsers and word processing applications can open text files. No special software or tools are necessary.

4. Data Acquisition and Processing:

Data Acquisition Methods:

Readings were taken by GPR and GPS to determine bedrock depth and position.

Bedrock depth chart

Map view of Roosevelt Island radar image of A-line; the bright reflector at the bottom is the bed

Locations were validated by GPS readings of poles set in the surface snow. The data was collected between November and December, 1997. The following map shows an "X" at each poles location and the traverse line in red. The traverse extends onto the ice shelf at each end. The positions are defined in the data file named checks.txt.

Pole location map

Traverse map

5. References and Related Publications:

Conway, H., B.L. Hall, G.H. Denton, A.M. Gades, E.D. Waddington. 1999. Past and Future Grounding-Line Retreat of the West Antarctic Ice Sheet. Science 286:280-283

6. Document Information:

Acronyms and Abbreviations

The following acronyms and abbreviations are used in this document.

FTP File Transfer Protocol
GPR Ground Penetrating Radar
GPS Global Positioning System

Document Creation Date:

2 May 2003

Document URL: