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| Titel |
Ice–ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers |
| VerfasserIn |
N. Chauché, A. Hubbard, J.-C. Gascard, J. E. Box, R. Bates, M. Koppes, A. Sole, P. Christoffersen, H. Patton |
| 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. 4 ; Nr. 8, no. 4 (2014-08-08), S.1457-1468 |
| Datensatznummer |
250116260
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| Publikation (Nr.) |
 copernicus.org/tc-8-1457-2014.pdf |
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| Zusammenfassung |
| Warm, subtropical-originating Atlantic water (AW) has been identified as a
primary driver of mass loss across the marine sectors of the Greenland Ice
Sheet (GrIS), yet the specific processes by which this water mass interacts
with and erodes the calving front of tidewater glaciers is frequently modelled
and much speculated upon but remains largely unobserved. We present a suite of
fjord salinity, temperature, turbidity versus depth casts along with
glacial runoff estimation from Rink and Store glaciers, two major marine
outlets draining the western sector of the GrIS during 2009 and 2010. We
characterise the main water bodies present and interpret their interaction
with their respective calving fronts. We identify two distinct processes of
ice–ocean interaction which have distinct spatial and temporal footprints:
(1) homogenous free convective melting which occurs across the calving front
where AW is in direct contact with the ice mass, and (2) localised upwelling-driven
melt by turbulent subglacial runoff mixing with fjord water which
occurs at distinct injection points across the calving front. Throughout the
study, AW at 2.8 ± 0.2 °C was consistently observed in
contact with both glaciers below 450 m depth, yielding homogenous,
free convective submarine melting up to ~200 m depth. Above
this bottom layer, multiple interactions are identified, primarily controlled
by the rate of subglacial fresh-water discharge which results in localised
and discrete upwelling plumes. In the record melt year of 2010, the Store
Glacier calving face was dominated by these runoff-driven plumes which led
to a highly crenulated frontal geometry characterised by large embayments at
the subglacial portals separated by headlands which are dominated by
calving. Rink Glacier, which is significantly deeper than Store has a larger
proportion of its submerged calving face exposed to AW, which results in a
uniform, relatively flat overall frontal geometry. |
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