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| Titel |
Modelling the spatial variability of accumulation across ice rises in Dronning Maud Land, Antarctica |
| VerfasserIn |
Denis Callens, Kenichi Matsuoka, Howard Conway, Frank Pattyn |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054999
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| Zusammenfassung |
| During two field campaigns (austral summer of 2008 and 2010), we collected radar data
across two ice rises within the ice shelf in Dronning Maud Land (Antarctica), i.e. the
FranKenny ice rise (promontory still connected to the main ice sheet) and the Derwael Ice
Rise, using both a 5 and 2 MHz radar system. Moreover, during the 2010 season, a number of
profiles were carried out with a high-frequency radar (400 MHz), penetrating to depths of
10-20m from the surface. Besides the bed reflection, a number of internal radar reflection
layers could be identified from the low-frequency radar data across both ice rises. These
layers show a remarkable variability in layer depth at both sides of the dome, pointing to a
variability in surface accumulation rates. This difference is also confirmed in the
high-frequency data. Based on several numerical ice sheet models of different complexity
(ranging from the Nye time scale to fully thermomechanically coupled shallow-ice and
higher-order ice sheet models), we modelled the geometry of several identified
isochrones either close to the surface and/or further down. Local accumulation
rates were obtained through inverse modelling. Results show that accumulation rate
vary with more than 40 % across the ridges. Although the precise reason of this
variation is still unknown, the distribution seems closely related with katabatic wind
redistribution. An analysis of the difference in accumulation distribution at both
sites as a function of the general pattern in katabatic wind distribution is presented. |
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