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AGU: Geophysical Research Letters

 

Keywords

  • Greenland
  • ice sheet
  • mass balance

Index Terms

  • Cryosphere: Mass balance
  • Cryosphere: Ice sheets
  • Cryosphere: Remote sensing
  • Cryosphere: Glaciology
  • Cryosphere: Glaciers

Abstract

Rates of southeast Greenland ice volume loss from combined ICESat and ASTER observations

Ian M. Howat

School of Earth Sciences and Byrd Polar Research Center, Ohio State University, Columbus, Ohio, USA

Ben E. Smith

Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA

Ian Joughin

Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA

Ted A. Scambos

National Snow and Ice Data Center, University of Colorado, Boulder, Colorado, USA

Repeat satellite laser altimetry is critical for observing the rapidly changing mass balance of the Greenland Ice Sheet. However, sparse sampling and high surface slopes over rapidly thinning, coastal outlet glaciers may result in underestimation of mass loss. Here we supplement ICESat-derived surface elevation changes with differenced ASTER digital elevation models of outlet glaciers in southeastern Greenland, the region with the largest concentrated change in outlet glacier mass loss. We estimate a 2002–2005 regional volume-loss rate of 108 km3/yr. Our results are consistent with drainage-scale GRACE and mass-budget estimates when differences in observation periods are taken into account. The two largest glaciers, Kangerdlugssuaq and Helheim, account for only 28% of the mass loss, illustrating the combined importance of smaller glaciers and the need for complete observational coverage. Additionally, we find that rapid, concentrated thinning within the outlets represents a small contribution to the total volume change compared to dispersed inland thinning.

Received 28 April 2008; accepted 29 July 2008; published 9 September 2008.

Citation: Howat, I. M., B. E. Smith, I. Joughin, and T. A. Scambos (2008), Rates of southeast Greenland ice volume loss from combined ICESat and ASTER observations, Geophys. Res. Lett., 35, L17505, doi:10.1029/2008GL034496.

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