Modeling seasonal velocity variability and assessing the influence of glacial hydrology and sea-ice buttressing at the Belcher Glacier, Arctic Canada
Abstract
Seasonal ice dynamics on marine outlet glaciers can be influenced by the effects of both glacial hydrology and sea-ice buttressing. In summer surface meltwater finds its way through crevasses and moulins into the subglacial drainage system thereby modulating the extent of glacier sliding. Whereas in winter sea-ice build-up in front of the glacier terminus provides a buttressing effect exerting a back stress on the glacier ice. In this study we seek to distinguish between contributions from these two processes at a large fast-flowing tidewater-terminating Arctic glacier. The Belcher Glacier is the largest outlet glacier of the Devon Island Ice Cap in the Canadian high-Arctic. We employ the use of a hydrologically coupled higher-order ice-flow model together with field data collected in 2008 and 2009. Model output is compared against surface GPS observations as well as remotely sensed velocities derived using speckle tracking methods on Radarsat-2 imagery. Five major drainage sub-catchments have been identified on the Belcher and a melt model is used to generate daily surface runoff for each sub-catchment. The observed timing of lake drainage and moulin openings in each sub-catchment allow a seasonal timeseries of meltwater inputs to the subglacial drainage system to be constructed. Model simulations for 2008 and 2009 forced with this meltwater input timeseries are presented. Model responses to tidal forcing and changes in sea-ice back stress at the terminus are examined and compared alongside hydrologically driven accelerations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.C23D0529P
- Keywords:
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- 0720 CRYOSPHERE / Glaciers;
- 0774 CRYOSPHERE / Dynamics;
- 0776 CRYOSPHERE / Glaciology;
- 0798 CRYOSPHERE / Modeling