80 Years of Frontal Changes of Marine-Terminating Glaciers in South-East Greenland
Abstract
Remote sensing data show that over the last decade the greatest mass loss from the Greenland Ice Sheet (GrIS) has been from the south-east (SE) region, primarily due to synchronous acceleration, thinning and retreat of marine-terminating outlet glaciers. These large dynamic changes have raised concerns about the future stability of the GrIS. We present an 80-year time-series of glacier margin positions for SE Greenland from the 1930s to 2010, together with snapshots of glacial thicknesses from trimlines and DEMs. Calving fronts were digitised from satellite imagery (Landsat, DISP, SAR), aerial photographs, as well as maps and oblique photographs from various expeditions. To extend the time-series beyond the observational record we additionally infer maximum Little Ice Age (LIA; 1150-1850) dimensions from vegetational trimlines. The two largest glaciers in the SE, Helheim and Kangerdlugssuaq, behave very differently over this timescale: Kangerdlugssuaq Glacier has gradually retreated ~20 km, whereas Helheim Glacier's August 2010 margin is within 2 km of the August 1933 position. Over the 80-year period Helheim was most retreated in 2005 and most advanced in 1985. From trimline evidence, the 1980s extent is comparable with the Little Ice Age maximum. Based on these data it is unlikely that Helheim Glacier has contributed to overall mass loss from the ice sheet since the LIA, whereas Kangerdlugssuaq has exhibited significant steady retreat. We compare the frontal positions of other glaciers in the SE including Gyldenlove, Bernstorff and Ikertivaq to determine whether the regionally widespread 2000s mass loss in SE Greenland is indicative of a longer-term contribution to sea-level rise from the region, or simply a rapid but short-lived fluctuation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.C23C0511G
- Keywords:
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- 0720 CRYOSPHERE / Glaciers;
- 0758 CRYOSPHERE / Remote sensing;
- 0776 CRYOSPHERE / Glaciology