Better boundary conditions for glacier and ice-sheet modelling

点击翻译按钮获取中文摘要

Glaciers and ice sheets store two-thirds of Earth's freshwater and are currently contributing to rising sea levels. While these ice masses act as long-term integrators of climate, their internal dynamics can complicate their behaviour on the short timescales relevant to society. Fundamental to our ability to decipher the underlying causes of glacier and ice-sheet change, and therefore pre-requisite to its reliable future projection, are accurate "boundary conditions" for glacier and ice-sheet models. The motivation for the proposed research is therefore to inform models we use to make projections of glacier change through process-based studies at the glacier surface and bed, and where the glacier comes into contact with freshwater reservoirs. The specific objectives of the research program are to (1) evaluate the robustness of glacier mass-balance models to uncertainties in accumulation processes, (2) develop statistical models of subglacial processes at scales commensurate with ice-sheet models and (3) investigate the influence of glacier-freshwater interactions on glacier dynamics and retreat. A fourth cross-cutting objective is to develop statistically robust practices for model calibration and to quantify associated model uncertainties. Observational, computational and statistical methods will be combined to achieve the above objectives in a number of individual studies suitable for graduate-level research. These studies involve new field work in British Columbia and Yukon to measure meteorological quantities, glacier mass balance, subglacial variables and properties of ice-marginal lakes. This research program capitalizes on emergent collaborations with local and international colleagues, as well as a new collaboration based at SFU between statisticians and earth scientists. It also involves partnership with local industry to develop novel instrumentation for monitoring subglacial properties. Built into the program are training opportunities for 6 new graduate students, along with 2 undergraduates and 1 northern community member per year. The anticipated impact of the research program will be an improved ability to (1) accurately model regional glacier mass-balance, (2) implement realistic representations of subglacial processes in large-scale ice-sheet models and (3) include glacier-freshwater feedbacks in future assessments of glacier change. Collectively, the proposed research will advance our understanding of externally driven- versus internally forced glacier change, toward more confident interpretations of short-term glacier variations and improved future projections. These projections are broadly relevant to issues of Canada's water security, economic development and environmental resilience.*** **