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| Titel |
A model study of Abrahamsenbreen, a surging glacier in northern Spitsbergen |
| VerfasserIn |
J. Oerlemans  , W. J. J. van Pelt |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 9, no. 2 ; Nr. 9, no. 2 (2015-04-27), S.767-779 |
| Datensatznummer |
250116783
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| Publikation (Nr.) |
 copernicus.org/tc-9-767-2015.pdf |
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| Zusammenfassung |
The climate sensitivity of Abrahamsenbreen, a 20 km long surge-type glacier
in northern Spitsbergen, is studied with a simple glacier model. A scheme to
describe the surges is included, which makes it possible to account for the
effect of surges on the total mass budget of the glacier. A climate
reconstruction back to AD 1300, based on ice-core data from Lomonosovfonna
and climate records from Longyearbyen, is used to drive the model. The model
is calibrated by requesting that it produce the correct Little Ice Age
maximum glacier length and simulate the observed magnitude of the
1978 surge.
Abrahamsenbreen is strongly out of balance with the current climate. If
climatic conditions remain as they were for the period 1989–2010, the
glacier will ultimately shrink to a length of about 4 km (but this will take
hundreds of years). For a climate change scenario involving a
2 m year−1 rise of the equilibrium line from now onwards, we
predict that in the year 2100 Abrahamsenbreen will be about 12 km long.
The main effect of a surge is to lower the mean surface elevation and
thereby to increase the ablation area, causing a negative perturbation of
the mass budget. We found that the occurrence of surges leads to a faster
retreat of the glacier in a warming climate.
Because of the very small bed slope, Abrahamsenbreen is sensitive to small
perturbations in the equilibrium-line altitude. If the equilibrium line were lowered
by only 160 m, the glacier would steadily grow into
Woodfjorddalen until, after 2000 years, it would reach Woodfjord and
calving would slow down the advance.
The bed topography of Abrahamsenbreen is not known and was therefore
inferred from the slope and length of the glacier. The value of the
plasticity parameter needed to do this was varied by +20 and −20%.
After recalibration the same climate change experiments were performed,
showing that a thinner glacier (higher bedrock in this
case) in a warming climate retreats somewhat faster. |
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