Investigating the association of thermal structure and glacier surging on the continental side of the St. Elias Mountains in Yukon, Canada

Abstract:

Glacier surges---quasi-periodic internal flow instabilities---remain among the most intriguing phenomena associated with a small fraction of the world’s glaciers. Surges occur across a range of geographical and environmental settings but are favored by a climate envelope in which polythermal glaciers are common. Thermally regulated surge events, which are restricted to polythermal glaciers, involve the transition from frozen (quiescence) to temperate (surging) basal conditions. Previous research from Svalbard has shown that surge-type glaciers there are likely to be polythermal, but little work has been done to investigate the connections between thermal structure and surging in other parts of the world. Here we focus on the St. Elias Mountains, which has one of the highest concentrations of surge-type glaciers in the world and has been among the highest regional contributors to sea-level rise in recent decades. We investigate how thermal structure varies with glacier geometry and size, along with the particular environmental setting that characterizes the continental side of the St. Elias Mountains in Yukon, Canada. As a first step, we will characterize the geometric attributes of surge-type glaciers in our study area using an existing compilation of surge-type glaciers to extract geometric characteristics (e.g. length, slope, elevation range, etc.) from open access data sets. We will then use extracted geometric attributes to create synthetic glacier geometries, representative of surge-type glaciers in the Yukon. In future work, the synthetic glacier geometries will be used as input to a thermomechanically coupled ice-flow model, along with representative climate conditions, to determine plausible steady-state thermal structures of surge-type glaciers within in our study area.