Ice flux divergence anomalies on 79north Glacier, Greenland

Publication: Research - peer-reviewJournal article – Annual report year: 2011

Documents

DOI

  • Author: Seroussi, H.

    California Institute of Technology

  • Author: Morlighem, M.

    California Institute of Technology

  • Author: Rignot, E.

    California Institute of Technology

  • Author: Larour, E.

    California Institute of Technology

  • Author: Aubry, D.

    École Centrale Paris, Laboratoire MSSMat

  • Author: Ben Dhia, H.

    École Centrale Paris, Laboratoire MSSMat

  • Author: Kristensen, Steen Savstrup

    IT-Department, National Space Institute, Technical University of Denmark, Ørsteds Plads, 2800, Kgs. Lyngby, Denmark

View graph of relations

The ice flux divergence of a glacier is an important quantity to examine because it determines the rate of temporal change of its thickness. Here, we combine high-resolution ice surface velocity observations of Nioghalvfjerdsfjorden (79north) Glacier, a major outlet glacier in north Greenland, with a dense grid of ice thickness data collected with an airborne radar sounder in 1998, to examine its ice flux divergence. We detect large variations, up to 100 m/yr, in flux divergence on grounded ice that are incompatible with what we know of the glacier surface mass balance, basal mass balance and thinning rate. We examine the hypothesis that these anomalies are due to the three-dimensional flow of ice around and atop bumps and hollows in basal topography by comparing the flux divergence of three-dimensional numerical models with its surface equivalent. We find that three-dimensional effects have only a small contribution to the observed anomalies. On the other hand, if we degrade the spatial resolution of the data to 10 km the anomalies disappear. Further analysis shows that the source of the anomalies is not the ice velocity data but the interpolation of multiple tracks of ice thickness data onto a regular grid using a scheme (here block kriging) that does not conserve mass or ice flux. This problem is not unique to 79north Glacier but is common to all conventional ice thickness surveys of glaciers and ice sheets; and fundamentally limits the application of ice thickness grids to high-resolution numerical modeling of glacier flow. Citation: Seroussi, H., M. Morlighem, E. Rignot, E. Larour, D. Aubry, H. Ben Dhia, and S. S. Kristensen (2011), Ice flux divergence anomalies on 79north Glacier, Greenland, Geophys. Res. Lett., 38, L09501, doi: 10.1029/2011GL047338.
Original languageEnglish
JournalGeophysical Research Letters
Publication date2011
Volume38
PagesL09501
ISSN0094-8276
DOIs
StatePublished
CitationsWeb of Science® Times Cited: 27
Download as:
Download as PDF
Select render style:
APAAuthorCBEHarvardMLAStandardVancouverShortLong
PDF
Download as HTML
Select render style:
APAAuthorCBEHarvardMLAStandardVancouverShortLong
HTML
Download as Word
Select render style:
APAAuthorCBEHarvardMLAStandardVancouverShortLong
Word

Download statistics

No data available

ID: 5588986