Here is my submitted abstract for the American Geophysical Union (AGU) Fall Meeting, San Francisco, 5-9 December, 2011.
“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.”
by Pimentel*, Flowers, Boon, Clavano, Copland, Danielson, Duncan, Kavanaugh, Sharp, and Van Wychen.
Update: The above abstract has been cancelled as I will no longer be able to attend the meeting.
I’m also an author on another abstract:
“We use local-scale subglacial hydrological models to assess the development of the basal drainage system in response to a rapid lake tapping event on the Russell Glacier catchment, SW Greenland. Water inputs to the model are constrained by in-situ records of the lake drainage rate. Subglacial conditions are estimated from active seismic line analysis including basal topography and substrate characteristics.
A borehole slug test model is used to determine the radial flux of water from the drainage input point. Water flowing in the downstream direction is used to drive a 1-D flowband model, which allows development of interacting channelised and distributed drainage systems. The simulated basal water pressures are applied to an elastic beam model to assess vertical uplift at the lake drainage site. Modelled uplift outputs are compared with results from GPS stations located next to the lake. Initial modelling results suggest that channels are necessary for evacuation of water from rapid lake drainage events, even with the presence of a sediment-based bed, the latter of which is usually associated with distributed drainage.”
by Dow*, Pimentel, Doyle, Booth, Fitzpatrick, Jones, Kulessa and Hubbard.