Warming of waters in an East Greenland fjord prior to glacier retreat: Mechanisms and connection to large-scale atmospheric conditions

Christoffersen, P, Mugford, RI, Heywood, KJ, Joughin, I, Dowdeswell, JA, Syvitski, JPM, Luckman, A and Benham, TJ (2011) Warming of waters in an East Greenland fjord prior to glacier retreat: Mechanisms and connection to large-scale atmospheric conditions. The Cryosphere, 5 (3). pp. 701-714. ISSN 1994-0440

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Abstract

Hydrographic data acquired in Kangerdlugssuaq Fjord and adjacent seas in 1993 and 2004 are used together with reanalysis from the NEMO ocean modelling framework to elucidate water-mass change and ice-ocean-atmosphere interactions in East Greenland. The hydrographic data show that the fjord contains warm subtropical waters and that fjord waters in 2004 were considerably warmer than in 1993. The ocean reanalysis shows that the warm properties of fjord waters in 2004 are related to a major peak in oceanic shoreward heat flux into a cross-shelf trough on the outer continental shelf. The heat flux into this trough varies according to seasonal exchanges with the atmosphere as well as from deep seasonal intrusions of subtropical waters. Both mechanisms contribute to high (low) shoreward heat flux when winds from the northeast are weak (strong). The combined effect of surface heating and inflow of subtropical waters is seen in the hydrographic data, which were collected after periods when along-shore coastal winds from the north were strong (1993) and weak (2004). The latter data were furthermore acquired during the early phase of a prolonged retreat of Kangerdlugssuaq Glacier. We show that coastal winds vary according to the pressure gradient defined by a semi-permanent atmospheric high-pressure system over Greenland and a persistent atmospheric low situated near Iceland. The magnitude of this pressure gradient is controlled by longitudinal variability in the position of the Icelandic Low.

Item Type: Article
Additional Information: © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License.
Faculty \ School: Faculty of Science > School of Environmental Sciences
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Depositing User: Rosie Cullington
Date Deposited: 31 May 2011 16:05
Last Modified: 05 Mar 2019 15:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/31623
DOI: 10.5194/tc-5-701-2011

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