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Titel |
Oceanic and atmospheric forcing of Larsen C Ice-Shelf thinning |
VerfasserIn |
P. R. Holland, A. Brisbourne, H. F. J. Corr, D. McGrath, K. Purdon, J. Paden, H. A. Fricker, F. S. Paolo, A. H. Fleming |
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. 3 ; Nr. 9, no. 3 (2015-05-13), S.1005-1024 |
Datensatznummer |
250116798
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Publikation (Nr.) |
copernicus.org/tc-9-1005-2015.pdf |
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Zusammenfassung |
The catastrophic collapses of Larsen A and B ice shelves on the eastern
Antarctic Peninsula have caused their tributary glaciers to accelerate,
contributing to sea-level rise and freshening the Antarctic Bottom Water
formed nearby. The surface of Larsen C Ice Shelf (LCIS), the largest ice
shelf on the peninsula, is lowering. This could be caused by unbalanced
ocean melting (ice loss) or enhanced firn melting and compaction (englacial
air loss). Using a novel method to analyse eight radar surveys, this study
derives separate estimates of ice and air thickness changes during a 15-year
period. The uncertainties are considerable, but the primary estimate is that
the surveyed lowering (0.066 ± 0.017 m yr−1) is caused by both ice loss
(0.28 ± 0.18 m yr−1) and firn-air loss (0.037 ± 0.026 m yr−1). The ice
loss is much larger than the air loss, but both contribute approximately
equally to the lowering because the ice is floating. The ice loss could be
explained by high basal melting and/or ice divergence, and the air loss by
low surface accumulation or high surface melting and/or compaction. The
primary estimate therefore requires that at least two forcings caused the
surveyed lowering. Mechanisms are discussed by which LCIS stability could be
compromised in the future. The most rapid pathways to collapse are offered by
the ungrounding of LCIS from Bawden Ice Rise or ice-front retreat past a
"compressive arch" in strain rates. Recent evidence suggests that either
mechanism could pose an imminent risk. |
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