Title 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
Author 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.; Young, N.
Author Affil Bindschadler, R., NASA, Goddard Space Flight Center, Greenbelt, MD. Other: University of Aberdeen, United Kingdom; University of Colorado at Boulder; British Antarctic Survey, United Kingdom; Alfred Wegener Institute for Polar and Marine Research, Germany; Scripps Institute of Oceanography; University of Maine; Norwegian Polar Institute, Norway; Earth and Space Research; University of Canterbury, New Zealand; Istituto Nazionale di Geofisica e Vulcanologia, Italy; University of Tasmania, Australia
Source The Cryosphere (Online), 5(3), p.569- 588, . Publisher: Copernicus on behalf of the European Geosciences Union, Katlenburg- Lindau, International. ISSN: 1994- 0424
Publication Date 2011
Notes In English. 35 refs. CRREL Acc. No: 66001788
Index Terms computer programs; computer applications; glacial geology; ice; ice cover; ice cover thickness; ice sheets; ice shelves; LANDSAT; lasers; remote sensing; tides; Antarctica--Antarctic ice sheet; Southern Ocean; altimetry; Antarctic ice sheet; Antarctica; Bakutis Coast; data processing; digital terrain models; Ekstrom ice shelf; ICESat; International Polar Year 2007-08; IPY 2007-08 Research Publications; Landsat; laser methods; ocean circulation; Princess Martha Coast; satellite methods; Scott Peninsula
Abstract Two ice-dynamic transitions of the Antarctic ice sheet - the boundary of grounded ice features and the freely-floating boundary - are mapped at 15-m resolution by participants of the International Polar Year project ASAID using customized software combining Landsat-7 imagery and ICESat/GLAS laser altimetry. The grounded ice boundary is 53 610 km long; 74% abuts to floating ice shelves or outlet glaciers, 19% is adjacent to open or sea-ice covered ocean, and 7% of the boundary ice terminates on land. The freely-floating boundary, called here the hydrostatic line, is the most landward position on ice shelves that expresses the full amplitude of oscillating ocean tides. It extends 27 521 km and is discontinuous. Positional (one-sigma) accuracies of the grounded ice boundary vary an order of magnitude ranging from 52 m for the land and open-ocean terminating segments to 502 m for the outlet glaciers. The hydrostatic line is less well positioned with errors over 2 km. Elevations along each line are selected from 6 candidate digital elevation models based on their agreement with ICESat elevation values and surface shape inferred from the Landsat imagery. Elevations along the hydrostatic line are converted to ice thicknesses by applying a firn-correction factor and a flotation criterion. BEDMAP-compiled data and other airborne data are compared to the ASAID elevations and ice thicknesses to arrive at quantitative (one-sigma) uncertainties of surface elevations of 3.6, 9.6, 11.4, 30 and 100 m for five ASAID-assigned confidence levels. Over one-half of the surface elevations along the grounded ice boundary and over one-third of the hydrostatic line elevations are ranked in the highest two confidence categories. A comparison between ASAID-calculated ice shelf thicknesses and BEDMAP-compiled data indicate a thin-ice bias of 41.2 71.3 m for the ASAID ice thicknesses. The relationship between the seaward offset of the hydrostatic line from the grounded ice boundary only weakly matches a prediction based on beam theory. 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.
URL http://www.the-cryosphere.net/5/569/2011/tc-5-569-2011.pdf
Publication Type journal article
Record ID 312141