Ice-penetrating radar for glacier dynamics studies

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The ongoing retreat of glaciers and icefields is contributing to sea-level rise and causing reduced streamflow in western Canada and most of the world's alpine regions.  The area of a glacier or icefield can be mapped with great precision through remote sensing, and observed areal changes in recent decades provide good information on glacier retreat.  Unless ice thickness is known, however, this cannot be converted to an estimate of glacier volume change.  It is the volume (or mass) of ice that matters for impacts on water resources and sea-level rise.  Models of glacier dynamics also require detailed spatial knowledge of ice thickness and subglacial bed topography, as the deformation and flux of ice scales with ice thickness to the fourth power.  The proposed ice-penetrating radar system is capable of sounding subglacial bed topography through several 100 m of ice. This will be deployed to map bedrock and ice thickness on several key index glaciers in western Canada.  Glacier thickness is presently unknown at these sites.  The radar system will be shared with groups at UBC, UNBC, SFU, and the University of Calgary and is expected to be fully committed over the next several field seasons, as we acquire this primary information on glaciers that are currently under study in our groups.  These measurements will feed into glaciological studies that have been initiated under the purview of the CFCAS-funded Western Canadian Cryospheric Network, 2006-2010 (B. Menounos, PI).  Part of our mandate within the network is to interpret recent changes and to provide forecasts of likely 21st-century glacier change. This study needs to include modelling efforts to capture important feedbacks associated with changes in ice dynamics as glacier geometry evolves.  Modelling is also needed to study the response time of different glaciers to specific climate perturbations (e.g., a heavy snow year or a warm summer).  Changes in glacier area or terminus position have an intrinsic time lag associated with the dynamical glacier response to climate change, and cannot be interpreted without models of ice dynamics.  Because such models require ice thickness data, the proposed radar system is central to progress within this project.