Subglacial processes and their large-scale consequences

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The leading aim of our research is to understand the operation of subglacial processes and to apply this understanding to improve computer models of the dynamics and hydrology of ice sheets. Inadequate representation of subglacial processes is a major shortcoming of the models that are currently used to predict Earth's glacial future. We need the best possible estimates of future rates of mass loss from polar ice sheets and the consequent rise in global sea level. Additionally, we need good models to increase understanding of past abrupt climate change events. Our strategy is to install instruments within and beneath glaciers to observe processes and their interactions, develop theory to encapsulate the results of these measurements and build numerical models to simulate the natural systems. We aim to extend the classical theory of subglacial drainage systems, based on water flow through circular ice-walled conduits, to include more realistic geometries. Applying these results, we can immediately improve physical models of subglacial and supraglacial outburst floods and develop, for the first time, a realistic model for eskers (a landscape feature) and, we hope, for other subglacial landforms. At a larger scale, we will continue our research on mechanisms of abrupt climate change, focussing on the role of megafloods, such as that from glacial Lake Agassiz, and on "Heinrich events" which seem to involve a coupled instability of water and ice flow. To complement our research on megafloods we will launch a modest field program to study the outburst floods and flood bedforms of Neoglacial Lake Alsek, Yukon.