Journal of Geophysical Research: Earth Surface

Volume and area changes of the Milne Ice Shelf, Ellesmere Island, Nunavut, Canada, since 1950

Authors

  • Colleen A. Mortimer,

    1. Department of Geography, University of Ottawa, Ottawa, Ontario, Canada
    2. Now at Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada
    Search for more papers by this author
  • Luke Copland,

    Corresponding author
    1. Department of Geography, University of Ottawa, Ottawa, Ontario, Canada
      Corresponding author: L. Copland, Department of Geography, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada. (luke.copland@uottawa.ca)
    Search for more papers by this author
  • Derek R. Mueller

    1. Department of Geography and Environmental Studies, Carleton University, Ottawa, Ontario, Canada
    Search for more papers by this author

Corresponding author: L. Copland, Department of Geography, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada. (luke.copland@uottawa.ca)

Abstract

[1] Ground penetrating radar (GPR) surveys of the 205 km2Milne Ice Shelf conducted in 2008 and 2009 are compared with radio echo sounding (RES) data from 1981 to provide the first direct measurements of thinning for any northern Ellesmere Island ice shelf. Our results show an average thinning for the ice shelf as a whole of 8.1 ± 2.8 m, with a maximum of >30 m, over this 28-year period. Direct-line comparisons along a 7.5 km transect near the front of ice shelf indicate a mean thinning of 2.63 ± 2.47 m over the same period. Reductions in areal extent (29%, 82 ± 8.4 km2: 1950–2009) and volume (13%, 1.5 ± 0.73 km3 water equivalent (w.e.): 1981–2008/2009) indicate that the Milne Ice Shelf has been in a state of negative mass balance for at least the last 59 years. A comparison of mean annual specific mass balance measurements with the nearby Ward Hunt Ice Shelf (WHIS) suggests that basal melt is a key contributor to Milne Ice Shelf thinning. Glacier inflow to the ice shelf has also reduced markedly over the past 28 years. The transition of ice shelf ice to lake ice was the most important source of mass loss. A 28.5 km2 epishelf lake now exists on the landward side of the ice shelf. Given these recent changes, disintegration of the Milne Ice Shelf will almost certainly continue in the future.

Ancillary