The role of atmospheric and oceanic forcing in Greenland outlet glacier behaviour

Satellite-derived sea surface temperature data and surface air temperature records from coastal Greenland weather stations were used to evaluate the respective roles of atmospheric and oceanic forcing on frontal position variations of Helheim, Kangerdlugssuaq Glacier and Jakobshavn Isbrae. At the seasonal scale, sea surface temperatures appear to be the dominant control on the cycle of frontal position changes at Kangerdlugssuaq Glacier and Jakobshavn, as a result of their controlling influence on sea ice concentration within the glacier fjords. At Helheim, glacier frontal position is seasonally sensitive to summer (JJA) air temperatures, likely as a result of meltwater enhancement of calving rates, although sea ice may also influence seasonal behaviour. At the interannual scale, glacier frontal positions show a similar sensitivity to the forcing factors that control seasonal variability, due to their influence on calving rates. Dramatic retreat of Kangerdlugssuaq may be attributed to reduced winter sea ice concentrations during over winter 2004 to 2005, following a two-year period of anomalously warm sea surface temperatures. Frontal retreat at Helheim is sensitive to annual surface air temperature anomalies and its first major retreat phase was concurrent with exceptionally high air temperatures in 2003, potentially as a result of hydrologically enhanced calving rates. In both cases, calving front retreat in excess of the usual seasonal cycle moved the glacier termini beyond a stable position, which subsequently facilitated dramatic retreat. A relatively low sea level pressure gradient between south-east Greenland and Iceland during winter 2002 to 2003 may have caused the sea surface and surface air temperature anomalies observed in the region during the following summers, concurrent the retreat of Helheim and Kangerdlugssuaq Glacier.

Name dc:type.qualificationname

Master of Philosophy (MPhil)

Level dc:type.qualificationlevel

Masters

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2008

Author dc:creator

• Carr, Rachel

• Glaciers
• Greenland
• Atmospheric forcing
• Oceanic forcing

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/649103df-8bac-427f-ba00-dc375bf36173/download
• https://www.rioxx.net/licenses/all-rights-reserved/

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.113250

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/375712