ABSTRACT: A glimpse at Canada’s deglacial future using regional glaciation modelling.

CGRG Bibliography of Canadian Geomorphology
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Abstract

Accurate predictions of the future volume and extent of glacier ice in Canada are essential for understanding the local impacts of glacial changes on agriculture, silvaculture, fisheries and hydroelectric power generation as well their contribution to global sea level rise. We have undertaken a modelling study of all (tens of thousands) of western Canada’s mountain glaciers with the aim of predicting their rates of change and future state. The ice flow model assumes the shallow-ice approximation and solves vertically-integrated two-dimensional balance equations for mass and momentum at a resolution of 200 m. Additional transport equations for thermal energy and for surface and englacial debris can be solved when warranted. Numerical modelling of glacier flow is straightforward but to do it well entails many challenges. Knowledge of subglacial topography is required as a boundary condition and thus strategies for estimating the thickness of existing ice cover need to be devised. Ice flow models are forced by climate but not in a direct manner: it is the imbalance of winter accumulation and summer melting that drives changes in glacial extent. Surface mass balance models, which relate the local accumulation or ablation of ice to large-scale climate fields, demand careful attention to the testing and validation of downscaling methodologies. We have demonstrated that climate fields extracted from the NCEP North American Regional Reanalysis (1979-present at 32 km resolution) can be successfullydownscaled and used to construct mass balance forcings that reproduce observed conditions. By applying the same downscaling strategies to computer-projected climate

Bibliography of Canadian Geomorphology