The Cryosphere Discuss., 5, 183-227, 2011
www.the-cryosphere-discuss.net/5/183/2011/
doi:10.5194/tcd-5-183-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal The Cryosphere (TC). Please refer to the corresponding final paper in TC.
Getting around Antarctica: new high-resolution mappings of the grounded and freely-floating boundaries of the Antarctic ice sheet created for the International Polar Year
R. Bindschadler1, H. Choi2, A. Wichlacz2, R. Bingham3, J. Bohlander4, K. Brunt5, H. Corr6, R. Drews7, H. Fricker8, M. Hall9, R. Hindmarsh6, J. Kohler10, L. Padman11, W. Rack7, G. Rotschky10, S. Urbini12, P. Vornberger2, and N. Young13
1Code 614.0, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
2SAIC, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
3University of Aberdeen, Aberdeen, AB24 3FX, UK
4National Snow and Ice Data Center, University of Colorado, Boulder, CO 80309-0449, USA
5Code 614.1, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
6British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
7Gateway Antarctica, University of Canterbury, Private Bag, Christchurch 8140, New Zealand
8Scripps Institute of Oceanography, University of California at San Diego, 9500 Giman Drive, La Jolla, CA 92093, USA
9Climate Change Institute, University of Maine, Orono, ME 04469, USA
10Norwegian Polar Institute, Polar Environmental Centre, 9296 Tromso, Norway
11ESR, 3350 SW Cascade Ave., Corvallis, OR 97333-1536, USA
12Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143 Rome, Italy
13Australian Antarctic Division, University of Tasmania, Kingston, Tasmania 7050, Australia

Abstract. The boundary of grounded ice and the location of ice transitioning to a freely floating state are mapped at 15-m resolution around the entire continent of Antarctica. These data products are produced by participants of the International Polar Year project ASAID using customized software combining Landsat-7 imagery and ICESat laser altimetry. The grounded ice boundary is 53 610 km long; 74% of it abuts to floating ice shelves or outlet glaciers, 19% is adjacent to open or sea-ice covered ocean, and 7% of the boundary are land terminations with bare rock. Elevations along each line are selected from 6 candidate digital elevation models: two created from the input ICESat laser altimetry and Landsat data, two from stereo satellite imagery, and two from compilations of primarily radar altimetry. Elevation selection and an assignment of confidence in the elevation value are based on agreement with ICESat elevation values and shape of the surface inferred from the Landsat imagery. Elevations along the freely-floating boundary (called the hydrostatic line) are converted to ice thicknesses by applying a firn-correction factor and a flotation criterion. The relationship between the seaward offset of the hydrostatic line from the grounding line only weakly matches a prediction based on beam theory. Airborne data are used to validate the technique of grounding line mapping, elevation selection and ice thickness derivation. The mapped products along with the customized software to generate them and a variety of intermediate products are available from the National Snow and Ice Data Center.

Citation: Bindschadler, R., Choi, H., Wichlacz, A., Bingham, R., Bohlander, J., Brunt, K., Corr, H., Drews, R., Fricker, H., Hall, M., Hindmarsh, R., Kohler, J., Padman, L., Rack, W., Rotschky, G., Urbini, S., Vornberger, P., and Young, N.: Getting around Antarctica: new high-resolution mappings of the grounded and freely-floating boundaries of the Antarctic ice sheet created for the International Polar Year, The Cryosphere Discuss., 5, 183-227, doi:10.5194/tcd-5-183-2011, 2011.
 
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