Glacier mass balance, dynamics and surface structures explored through numerical modelling, with application to the St. Elias Mountains of Yukon, Canada

This thesis presents an investigation of the impacts of glacier change in the St. Elias Mountains of Northern Canada, by considering both non-surge-type and surge-type glaciers. First, the 2007-2018 mass balance of the Kaskawulsh Glacier is characterized. This work combines geodetic, field, and climate reanalysis datasets to develop a distributed mass balance modelling methodology and determine the extent of the Kaskawulsh Glacier's dynamic response to the early 21st century climate. A mass balance rate for 2007-2018 of -0.46 ± 0.17 m w.e. a-1 is computed, and a committed terminus retreat of 23.2 ± 3.2 km corresponding to a lower bound for ice loss of 46 km3, or ~15% of the total glacier volume is projected. It is identified that the glacier is in the early stages of dynamic readjustment by comparing balance and calculated discharges at 11 transects in the ablation zone. Second, a numerical modelling approach to emulating glacier surges is developed to investigate the macro-scale structural glaciology of surge-type glaciers. The sensitivity of valley-scale fold geometry to both mass balance and basal sliding forcings is assessed in a synthetic system. These results are used to construct and describe the 3-D kinematic evolution of passive folding in surge-type glaciers, folds that correspond to iconic folded medial moraines on the ice surface of glaciers in nature. Additionally, a criterion for qualitatively evaluating the past surge dynamics of surge-type glaciers based on the geometry of their folded moraines is proposed. Third, both the mass balance and the numerical ice flow models developed and tested in the previous steps are combined to reconstruct the surge kinematics of the Dusty Glacier's 2001-2003 surge. The results of this modelling experiment are used to delve into the possible ice flow history of the Dusty Glacier during the past two centuries encompassing five glacier surges, and discuss further application of the method in light of this successful deployment.