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| Titel |
Surface velocity and mass balance of Livingston Island ice cap, Antarctica |
| VerfasserIn |
B. Osmanoglu, F. J. Navarro, R. Hock, M. Braun, M. I. Corcuera |
| 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 ; 8, no. 5 ; Nr. 8, no. 5 (2014-10-08), S.1807-1823 |
| Datensatznummer |
250116321
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| Publikation (Nr.) |
 copernicus.org/tc-8-1807-2014.pdf |
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| Zusammenfassung |
| The mass budget of the ice caps surrounding the Antarctica Peninsula and, in
particular, the partitioning of its main components are poorly known. Here we
approximate frontal ablation (i.e. the sum of mass losses by calving and
submarine melt) and surface mass balance of the ice cap of Livingston Island,
the second largest island in the South Shetland Islands archipelago, and
analyse variations in surface velocity for the period 2007–2011. Velocities
are obtained from feature tracking using 25 PALSAR-1 images, and
used in conjunction with estimates of glacier ice thicknesses inferred from
principles of glacier dynamics and ground-penetrating radar observations to
estimate frontal ablation rates by a flux-gate approach. Glacier-wide surface
mass-balance rates are approximated from in situ observations on two glaciers
of the ice cap. Within the limitations of the large uncertainties mostly due
to unknown ice thicknesses at the flux gates, we find that frontal ablation
(−509 ± 263 Mt yr−1, equivalent to
−0.73 ± 0.38 m w.e. yr−1 over the ice cap area of
697 km2) and surface ablation (−0.73 ± 0.10 m w.e. yr−1)
contribute similar shares to total ablation
(−1.46 ± 0.39 m w.e. yr−1). Total mass change
(δM = −0.67 ± 0.40 m w.e. yr−1) is negative despite a slightly
positive surface mass balance (0.06 ± 0.14 m w.e. yr−1). We
find large interannual and, for some basins, pronounced seasonal variations
in surface velocities at the flux gates, with higher velocities in summer
than in winter. Associated variations in frontal ablation (of
~237 Mt yr−1; −0.34 m w.e. yr−1) highlight the
importance of taking into account the seasonality in ice velocities when
computing frontal ablation with a flux-gate approach. |
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