Rapid circulation of warm subtropical waters in a major glacial fjord in East Greenland

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Date
2009-12-17Author
Straneo, Fiamma
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Hamilton, Gordon S.
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Sutherland, David A.
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Stearns, Leigh A.
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Davidson, Fraser J. M.
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Hammill, Mike O.
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Stenson, Garry B.
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Rosing-Asvid, Aqqalu
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https://hdl.handle.net/1912/3908As published
https://doi.org/10.1038/ngeo764Abstract
The recent rapid increase in mass loss from the Greenland Ice Sheet is primarily
attributed to an acceleration of outlet glaciers. One possible cause is increased
melting at the ice/ocean interface driven by the synchronous warming of
subtropical waters offshore of Greenland. This hypothesis is largely untested,
however, because of the lack of observations from Greenland’s glacial fjords and
our limited understanding of their dynamics. Here, we present new ship-based and
moored oceanographic data, collected in Sermilik Fjord, a large glacial fjord in East
Greenland, showing that subtropical waters are present throughout the fjord and
are continuously replenished via a wind-driven exchange with the shelf, where they
occur year-round. The temperature and rapid renewal of these waters suggest that,
at present, they drive enhanced submarine melting at the terminus. Key controls on
the melting rate are the volume and properties of subtropical waters on the shelf
and the patterns of the along-shore winds, suggesting the glaciers’ acceleration
was triggered by a combination of atmospheric and oceanic changes. These
measurements provide evidence of rapid advective pathway for the transmission of
oceanic variability to the ice-sheet margins and highlight an important process that
is missing from prognostic ice-sheet models.
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Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Geoscience 3 (2010): 182-186, doi:10.1038/ngeo764.