A decade of ocean changes impacting the ice shelf of Petermann Gletscher, Greenland

Washam, P.; Münchow, A.; Nicholls, Keith W. ORCID: https://orcid.org/0000-0002-2188-4509. 2018 A decade of ocean changes impacting the ice shelf of Petermann Gletscher, Greenland. Journal of Physical Oceanography, 48 (10). 2477-2493. https://doi.org/10.1175/JPO-D-17-0181.1

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Official URL: http://dx.doi.org/10.1175/JPO-D-17-0181.1

Abstract/Summary

Hydrographic data collected during five summer surveys between 2002 and 2015 reveal that the subsurface ocean near Petermann Gletscher, Greenland warmed by 0.015 ± 0.013°C yr-1. New 2015 - 2016 mooring data from beneath Petermann Gletscher’s ice shelf imply a continued warming of 0.025 ± 0.013°C yr-1 with a modest seasonal signal. In 2015 we measured ocean temperatures of 0.28°C near the grounding line of Petermann Gletscher’s ice shelf, which drove submarine melting along the base of the glacier. The resultant meltwater contributed to ocean stratification, which forced a stronger geostrophic circulation at the ice shelf terminus compared with previous years. This increased both the freshwater flux away from the sub-ice shelf cavity and the heat flux into it. Net summertime geostrophic heat flux estimates into the sub-ice shelf cavity exceed the requirement for steady-state melting of Petermann Gletscher’s ice shelf. Likewise, freshwater fluxes away from the glacier exceed the expected steady-state meltwater discharge. These results suggest that the warmer, more active ocean surrounding Petermann Gletscher forces “non steady-state” melting of its ice shelf. When sustained, such melting thins the ice shelf.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1175/JPO-D-17-0181.1
ISSN:	0022-3670
Additional Keywords:	ocean, Arctic, ice shelves, buoyancy, ocean circulation, in situ oceanic observations
Date made live:	20 Sep 2018 12:56 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/521018

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1175/JPO-D-17-0181.1

ISSN:

0022-3670

Additional Keywords:

ocean, Arctic, ice shelves, buoyancy, ocean circulation, in situ oceanic observations

Date made live:

20 Sep 2018 12:56 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/521018