1Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, UK
2University of Cambridge, Scott Polar Research Institute, Cambridge UK
3University of Kansas, Center for Remote Sensing Ice Sheets, Lawrence, Kansas, USA
4Ohio State University, School of Earth Sciences, Columbus, Ohio, USA
5Ohio State University, Byrd Polar Research Center, Columbus, Ohio USA
6University of California Irvine, Department of Earth System Sciences, Irvine, California, USA
7Jet Propulsion Laboratory, Pasadena, California, USA
8Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
Received: 26 Oct 2012 – Discussion started: 15 Nov 2012
Abstract. We present a new bed elevation dataset for Greenland derived from a combination of multiple airborne ice thickness surveys undertaken between the 1970s and 2012. Around 420 000 line kilometres of airborne data were used, with roughly 70% of this having been collected since the year 2000, when the last comprehensive compilation was undertaken. The airborne data were combined with satellite-derived elevations for non-glaciated terrain to produce a consistent bed digital elevation model (DEM) over the entire island including across the glaciated–ice free boundary. The DEM was extended to the continental margin with the aid of bathymetric data, primarily from a compilation for the Arctic. Ice thickness was determined where an ice shelf exists from a combination of surface elevation and radar soundings. The across-track spacing between flight lines warranted interpolation at 1 km postings for significant sectors of the ice sheet. Grids of ice surface elevation, error estimates for the DEM, ice thickness and data sampling density were also produced alongside a mask of land/ocean/grounded ice/floating ice. Errors in bed elevation range from a minimum of ±10 m to about ±300 m, as a function of distance from an observation and local topographic variability. A comparison with the compilation published in 2001 highlights the improvement in resolution afforded by the new datasets, particularly along the ice sheet margin, where ice velocity is highest and changes in ice dynamics most marked. We estimate that the volume of ice included in our land-ice mask would raise mean sea level by 7.36 m, excluding any solid earth effects that would take place during ice sheet decay.
Revised: 05 Mar 2013 – Accepted: 06 Mar 2013 – Published: 22 Mar 2013
Bamber, J. L., Griggs, J. A., Hurkmans, R. T. W. L., Dowdeswell, J. A., Gogineni, S. P., Howat, I., Mouginot, J., Paden, J., Palmer, S., Rignot, E., and Steinhage, D.: A new bed elevation dataset for Greenland, The Cryosphere, 7, 499-510, doi:10.5194/tc-7-499-2013, 2013.