Data Set ID:
NSIDC-0626

Inverted Basal Shear Stress of Antarctic and Greenland Ice Streams and Glaciers, Version 1

This data set includes basal shear distributions inferred from surface observations - surface ice velocities (Joughin et al., 2010, Rignot et al., 2011), bed and surface elevations (Fretwell et al., 2013) under ten selected locations in Greenland and Antarctica. In Greenland, the locations were: 79° North and Zachariae Glaciers, Jakobshan Isbrae, North East Greenland Ice Stream, Petermann Glacier. The Antarctica locations were Bindschadler Ice Stream, Lambert Ice Stream, MacAyeal Ice Stream, Pine Island Glacier, Thwaites Glacier, and an unnamed location around ~40° E 84° S.

Get Data

NSIDC does not archive these data.

Geographic Coverage

Parameter(s):
  • Glaciers/Ice Sheets > Basal Shear Stress
Spatial Coverage:
  • N: -75, S: -90, E: 60, W: -150

  • N: 84, S: 60, E: -20, W: -75

Spatial Resolution:
  • 500 m
Temporal Coverage:
  • 1 June 2009 to 31 July 2013
Temporal Resolution: Not specified
Data Format(s):
  • MATLAB
  • NetCDF
Platform(s) GROUND-BASED OBSERVATIONS
Sensor(s): VISUAL OBSERVATIONS
Version: V1
Data Contributor(s): Olga Sergienko
Please contact the data provider for the correct Data Citation for this data set.

Literature Citation

As a condition of using these data, we request that you acknowledge the author(s) of this data set by referencing the following peer-reviewed publication.

  • Sergienko, O. and R. C. Hindmarsh. 2013. Regular Patterns in Frictional Resistance of Ice-Stream Beds Seen by Surface Data Inversion, Science. 342. 11086-1089. https://doi.org/10.1126/science.1243903.

  • Sergienko, O., T. T. Creyts, and R. C. Hindmarsh. 2014. Similarity of organized patterns in driving and basal stresses of Antarctic and Greenland ice sheets beneath extensive areas of basal sliding, Geophysical Research Letters. 41. 3925–3932. https://doi.org/10.1002/2014GL059976

Back to Top

Collapse All / Open All

Detailed Data Description

This data set includes basal shear distributions inferred from surface observations - surface ice velocities (Jougin et al, 2010Rignot et al, 2011), bed and surface elevations (Fretwell et al, 2013) under ten selected locations in Greenland and Antarctica. In Greenland, the locations were: 79° North and Zachariae Glaciers, Jakobshan Isbrae, North East Greenland Ice Stream, Petermann Glacier. The Antarctica locations were Bindschadler Ice Stream, Lambert Ice Stream, MacAyeal Ice Stream, Pine Island Glacier, Thwaites Glacier, and an unnamed location around ~40° E 84° S. Figure 1 shows the driving stress (kPa) of Antarctica and Greenland. Rectangles outline areas where inversion for basal traction were preformed. See Table 1 for the specific ice stream or glacier outlined. (Sergienko 2014)

filedirectory
Figure 1. Driving stress (kPa) of (a) Antarctic ice sheet and (b) Greenland ice sheet
Table 1. Outlined Glaciers/Ice Streams Designation
Rectangle Ice Stream/Glacier Name
Antarctica
B Bindschadler Ice Stream
M MacAyeal Ice Stream
E Unnamed location at 40° E, 84° S
L Lambert Ice Stream
Greenland
P Petermann Glacier
J Jakobshavn Isbræ
NZ 79° North and Zachariæ glaciers
N North-East Greenland Ice Stream (NEGIS)

The detailed description of the inversion procedure and discussion of the results are provided in Sergienko and Hindmarsh (2013) for Pine Island and Thwaites Glaciers (Antarctica) and Sergienko, Creyts and Hindmarsh (2014) for all other locations. The inversion procedure utilized a full-Stokes, three-dimensional finite-element model of variable horizontal resolutions (1/6 to 1/3 of the local ice thickness) using irregular domains (Sergienko and Hindmarsh 2013, Sergienko et al. 2014). Tikhonov regularizations have been utilized in all inversions.

Format

Data are in MATrix LABoratory (MATLAB) (.mat) and Network Common Data Form (netCDF) (.nc) formats.

Background color on
File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0626_sergienko/ directory. Within this directory, there is one .zip file, NSF0934534.zip. Within the .zip file, there are two folders, Antarctica and Greenland. The Antarctica folder contains 12 files and the Greenland folder contains 8 files.

Background color on
File Naming Convention

There are two files for each location: .mat and .nc. See Figure 2 for a listing of the files.

filedirectory
Figure 2. File Directory

Data are in rectangular arrays. Table 2 describes the arrays.

Table 2. Rectangular Array Descriptions
Variable Description
X Easting coordinate (m)
Y Northing coordinate (m)
Taub Basal shear stress (kPa)
Background color on
File Size

File size ranges from 111 KB to 4,827 KB.

Background color on
Volume

The data set is ~20 MB.

Background color on
Spatial Coverage

The data represents multiple glaciers and ice streams at the following locations:
Greenland: 84° N 20° W to 60° N 75° W
Antarctica: 75° S 60° E to 90° S 150° W

Spatial Resolution

Spatial resolution is 500 m.

Projection and Grid Description

Data sets are on polar stereogarphic projections described by Fretwell et al. (2013) for Antarctic locations and Bamber et al. (2013) for Greenland locations.

Background color on
Temporal Coverage

Data were collected from 01 June 2009 to 31 July 2013.

Background color on
Parameter or Variable

Basal Shear Stress

Sample Data Record

Refer to Figures 3 and 4 for examples of the data.

.mat files
Figure 3. Sample of .mat files
.mat files
Figure 4. Sample of .nc files
Background color on

Software and Tools

In order to view the netCDF files, you can download a free tool from NASA: Panoply netCDF, HDF, and GRIB Data Viewer.
The MATLAB files can be accessed using MATLAB.

Background color on

Data Acquisition and Processing

Data Acquisition Methods

Basal shear distributions under ten selected locations in Greenland (79° North and Zacharia Glaciers, Jakobshan Isbrae, North East Greenland Ice Stream, Petermann Glacier) and Antarctica (Bindschadler Ice Stream, Lambert Ice Stream, MacAyeal Ice Stream, Pine Island Glacier, Thwaites Glacier, Unnamed location around ~40° E 84° S) were inferred from surface observations - surface ice velocities (Jougin et al. 2010Rignot et al. 2011), and bed and surface elevations (Fretwell et al. 2013Bamber et al. 2013).

Background color on
Derivation Techniques and Algorithms

Processing Steps

The inversion procedure utilized a full-Stokes, three-dimensional finite-element model of variable horizontal resolutions (1/6 to 1/3 of the local ice thickness) using irregular domains (Sergienko and Hindmarsh (2013), Sergienko, Creyts, and Hindmarsh (2014)). Tikhonov regularizations have been utilized in all inversions. The detailed description of the inversion procedure and discussion of the results are provided in Sergienko and Hindmarsh (2013) for Pine Island and Thwaites Glaciers (Antarctica) and Sergienko, Creyts. (2014) for all other locations.

For this data set, inversion outputs were bi-linearly interpolated (with interp2 Matlab command) on a rectangular, 500 m resolution grid. Values outside the study domains are NaN in the Matlab format files (.mat) and -9999 in the Network Common Data Form (.nc) files.

Background color on

References and Related Publications

Contacts and Acknowledgments

Olga Sergienko
Princeton University
Atmospheric and Oceanic Science
GFDL, 201 Forrestal Rd, Office 347
Princeton, NJ 08544 USA

Acknowledgments: 

This research was funded by National Science Foundation (NSF) grant number 034534.

Document Information

Document Creation Date

15 June 2015

No technical references available for this data set.
No FAQs or How Tos available for this data set.

Access complete Knowledge Base

Questions? Please contact:
NSIDC User Services
Phone: 1 303 492-6199
Email: nsidc@nsidc.org