Histories of Accumulation, Thickness, and WAIS Divide Location, Antarctica

Summary

This data set contains radar internal layer and ice sheet topography data for two sites in Antarctica, along with associated model results from two studies. This project used geophysical inverse theory and a 2.5 D flowband ice-flow forward model to extract robust transient accumulation patterns from multiple deeper layers. Histories of divide migration, or the movement of the ice sheet and ice-surface evolution are also provided. The data used to solve the inverse problem, and the model solutions are provided. Internal layers, modern ice-surface velocities, and modern ice-sheet geometry at Taylor Mouth are available, as well as the pattern of accumulation inferred by Waddington et al. (2007).

Data are available via FTP in Matlab (.mat) format. Supporting information is available as text files (.rtf and .txt).

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, publisher: NSIDC, and digital media.

Waddington, E., and M. Koutnik. 2010. Histories of Accumulation, Thickness, and WAIS Divide Location, Antarctica. Boulder, Colorado, USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5QR4V2J.

Overview Table

Category	Description
Data format	Matlab (.mat), Rich Text Format (.rtf), and text (.txt)
Spatial coverage and resolution	Taylor Mouth Southernmost Latitude: 77º 47' S Northernmost Latitude: 77º 47' S Westernmost Longitude: 158º 43' E Easternmost Longitude: 158º 43' E West Antarctic Ice Sheet Divide Southernmost Latitude: 79° 25' S Northernmost Latitude: 79° 25' S Westernmost Longitude: 111° 49' W Easternmost Longitude: 111° 49' W
Temporal coverage and resolution	Radar data were collected during two Antarctic field seasons, 2002 to 2003 and 2003 to 2004.
File naming convention	tm_data.mat tm_data.rtf tm_results.mat tm_results.rtf
File size	Files range in size from 2 KB to 19 KB.
Parameter(s)	Ice Surface Velocity Accumulation Rate Bedrock Elevation Ice Surface Slope Ice Thickness Layer Ages Layer Depth
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

Investigators

Dr. Edwin D. Waddington
Department of Earth and Space Sciences
University of Washington
Seattle, Washington 98195
USA

Dr. Michelle Koutnik
Department of Earth and Space Sciences
University of Washington
Seattle, Washington 98195
USA

Technical Contact

Acknowledgements

This research was supported by NSF OPP grant 0440666.

2. Detailed Data Description

Format

Data and models are available in Matlab (.mat) format. Each Matlab file also has an associated text file with supporting information, available in .rtf or .txt format.

File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/DATASETS/AGDC/nsidc0473_waddington_v01/ directory. Within this directory, there are three Matlab files, each with an associated .rtf file that describes the data columns. There are also two associated text files, wais_u_geometry.txt and wais_bdot.txt.

File Naming Convention

Files are named according to the following convention and as described in Table 1:

SN_type.mat

Where:

Table 1. File Naming Convention

Variable	Description
SN	Site Name: tm: Taylor Mouth wais: West Antarctic Ice Sheet Divide
type	Record type: data or results
.mat	Matlab file extension

Example: wais_data.mat is a Matlab file containing data from the West Antarctic Ice Sheet divide site. Descriptions of each variable in the file are provided in the associated wais_data.rtf file.

File Size

Files range in size from 2 KB to 19 KB.

Spatial Coverage

Data are based on radar data collected at two locations in Antarctica:

Taylor Mouth
Southernmost Latitude: 77º 47' S
Northernmost Latitude: 77º 47' S
Westernmost Longitude: 158º 43' E
Easternmost Longitude: 158º 43' E

West Antarctic Ice Sheet Divide
Southernmost Latitude: 79° 25' S
Northernmost Latitude: 79° 25' S
Westernmost Longitude: 111° 49' W
Easternmost Longitude: 111° 49' W

Temporal Coverage

Radar data were collected during two Antarctic field seasons, 2002 to 2003 and 2003 to 2004.

Parameter or Variable

Variables in this model data set include Ice Surface Velocity, Accumulation Rate, Bedrock Elevation, Ice Surface Slope, Ice Thickness, Layer Ages, and Layer Depth. The variables for each of the Matlab (.mat) files are described in the text file of the same name. Model data are based upon radar measurements of surface velocity, surface topography, and ice thickness, collected by H. Conway and L. A. Rasmussen.

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

Total volume of the data set is approximately 52 KB.

Software and Tools

Data are accessible using Matlab software.

4. Data Acquisition and Processing

Theory of Measurements

This data set provides model data and model results, from a study of accumulation patterns from deep layers of Antarctic ice sheets. The investigators built models based on radar data. For more information on methods, see Waddington, et. al., 2007 and Neumann, et al., 2008.

Sensor or Instrument Description

These model data are based upon radar data collected with ice-penetrating radar, on the Antarctic Ice Sheet.

5. References and Related Publications

Conway, H. and L. A. Rasmussen. 2009. Recent thinning and migration of the Western Divide, central West Antarctica. Geophysical Research Letters 36, doi: 10.1029/2009GL038072.

Neumann, T. A., H. Conway, S. F. Price, E. D. Waddington, G. A. Catania, and D. L. Morse. 2008. Holocene accumulation and ice sheet dynamics in central West Antarctica. Journal of Geophysical Research 113, doi: 10.1029/2007JF000764.

Steen-Larsen, H. C., E. D. Waddington, and M. R. Koutnik. 2010. Formulating an inverse problem to infer the accumulation-rate pattern from deep internal layering in an ice sheet using a Monte-Carlo approach. Journal of Glaciology. In Press.

Waddington, E. D., T. A. Neumann, M. R. Koutnik, H. P. Marshall, and D. L. Morse. 2007. Inference of accumulation-rate patterns from deep layers in glaciers and ice sheets. Journal of Glaciology 53(183), 694-712.

6. Document Information

Acronyms

The acronyms used in this document are listed in Table 2.

Table 2. Acronyms and Abbreviations

Acronym	Description
FTP	File Transfer Protocol
.MAT	Matlab File Extension
NSIDC	National Snow and Ice Data Center
URL	Uniform Resource Locator

Document Creation Date

8 July 2010

Document URL

http://nsidc.org/data/docs/agdc/nsidc0473_waddington/index.html