Integrated Climate Data Center
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Ice velocity of Antarctic Ice Sheet

Access

Internal access for ZMAW users:

Data access via file system: /data/icdc/ice_and_snow/antarctic_glac/

or email to: icdc@zmaw.de

 

No access limitations:

Obtain data directly from NSIDC

Description

The ice velocity of the Antarctic ice sheet's outlet glaciers and the areas feeding these glaciers are an important parameter for the quantification of the mass balance of the ice sheet and ice shelves, and for its future development. The break-up or disintegration of such an entire ice shelf like the Larsen Ice Shelf, or the Wilkens Ice Shelf can substantially impact the ice velocity of the glaciers that (used to) feed these ice shelves. A correct quantification of the ice velocity is therefore important also to gain a better knowledge about the future stability of the glacier itself and of the ice sheet areas upstream feeding this glacier.


Ice velocities are derived using Synthetic Aperture Radar (SAR) data. One way is to track speckle in both along (azimuth) and across (range) track directions and by calculation of the two dimensional offsets in amplitude imagery derive the ice velocity. The second approach is to combine the interferometric phases of two independent tracks to retrieve the surface flow vector.


Data from a number of different SAR sensors are used for this dataset: RADARSAT-1 und -2 SAR, Envisat ASAR, ALOS Palsar und ERS1/2 SAR.


Details can be taken from the references down below.

 

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Parameters

Name Unit
velocity x-direction m/year
velocity y-direction m/year
velocity uncertainty m/year
   

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Coverage, spatial and temporal resolution

Period and temporal resolution:

  • 1996 to 2011
  • no temporal resolution; composit of data from the above-mentioned years

Coverage and spatial resolution:

  • Antarctic
  • Spatial resolution: 900 m x 900 m, polar-stereographic grid, centred at 71°S
  • Geographic longitude: 0°E to 360°E
  • Geographic latitude: south of 60°S
  • Dimension:
  • Altitude: following terrain

Format:

  • NetCDF (one file, size: 350 Mbyte)

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Data quality

The dataset contains an uncertainty estimation. The precision of ice flow mapping varies with the sensor, the geographic location, the technique of interferometric analysis, the time period of analysis, the repeat cycle, and the amount of data stacking. The total error is the square root of the sum of the independent errors squared and ranges between about 1 m/year for ERS1/2 and around 10 m/year for ALOS Palsar. These estimates, however, should be used more as an indication of relative quality rather than absolute error.

We recommend the documentation and the publications listed in references down below for further reading.

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Contact

Dr. Eric Rignot
University of California, Irvine
Department of Earth System Science
Croul Hall, Irvine, California 92697, USA 

email: eric.rignot@jpl.nasa.gov or erignot@uci.edu 

NSIDC User Services 
 National Snow and Ice Data Center 
 CIRES, 449 UCB 
University of Colorado 
 Boulder, CO 80309-0449, USA

e-mail: nsidc@nsidc.org

 

Stefan Kern 
CliSAP / KlimaCampus / ICDC 
Email: stefan.kern@zmaw.de

 

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References

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Data citation

Please cite usage of this data as follows:

Rignot, E., J. Mouginot, and B. Scheuchl. 2011. MEaSUREs InSAR-Based Antarctica Velocity Map. Boulder, Colorado USA:
NASA EOSDIS Distributed Active Archive Center at NSIDC. [list dates of data used]. nsidc.org/data/nsidc-0484.html

and additionally:

Rignot, E., J. Mouginot, and B. Scheuchl. 2011. Ice Flow of the Antarctic Ice Sheet, Science, Vol. 333(6048): 1427-1430. doi 10.1126/science.1208336.

 
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