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| Titel |
Ice dynamics of Bowdoin tidewater glacier, Northwest Greenland, from borehole measurements and numerical modelling |
| VerfasserIn |
Julien Seguinot, Martin Funk, Claudia Ryser, Guillaume Jouvet, Andreas Bauder, Shin Sugiyama |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250131221
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| Publikation (Nr.) |
 EGU/EGU2016-11604.pdf |
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| Zusammenfassung |
| The observed rapid retreat of ocean-terminating glaciers in southern Greenland in the last two
decades has now propagated to the northwest. Hence, tidewater glaciers in this area, some of
which have remain stable for decades, have started retreating rapidly through iceberg calving
in recent years, thus allowing a monitoring and investigation of ice dynamical changes
starting from the early stages of retreat.
Here, we present an ice dynamical study from Bowdoin Glacier, a tidewater outlet glacier
located at the northwestern margin of the Greenland Ice Sheet. The glacier surface
experiences lowering at a rate of 1.5 m/a since 2007. A rapid calving front retreat of 260 m/a
was also observed since 2008, while no significant changes occurred during the
previous 20 years. From July 2014 to July 2015, we monitored, 2 km upstream
from the calving front, subglacial water pressure changes in boreholes, internal ice
deformation through tilt sensors at different depths, englacial ice temperature profiles
from the glacier bed to the surface, and high resolution surface motion from GPS
records. These measurement show that the glacier is temperate-based, yet internal
deformation accounts for about 10 % of the annual surface motion. A seasonal increase in
both deformation and sliding at the onset of the melt season is associated with a
drop in water pressure in part of the subglacial system. These observations are
used to calibrate the Parallel Ice Sheet Model (PISM) for numerical simulations of
ice flow in the Bowdoin Glacier catchment, aiming for a better understanding of
iceberg calving processes in relation to changes in internal and basal ice dynamics. |
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