A theory of glacier dynamics and instabilities Part 1: Topographically confined glaciers

• Published in: Journal of Glaciology
• Main Author: Hsien-Wang Ou
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2022
• Subjects: Glacier flow; glacier modeling; glacier surges; ice dynamics; subglacial processes; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; Svalbard; Greenland; Hudson; Hudson Strait; glacier; Journal of Glaciology
• Online Access: https://doi.org/10.1017/jog.2021.20; https://doaj.org/article/4578f726e04645acb2bf1fc4f4c247a0

We present a theoretical framework that integrates the dynamics of glaciers with and without the topographic confinement. This Part 1 paper concerns the former, which may exhibit surge cycles when subjected to thermal switches associated with the bed condition. With the topographic trough setting the glacier width and curbing the lateral drainage of the meltwater, the problem falls under the purview of the undrained plastic bed (UPB) formalism. Employing the UPB, we shall examine the external controls of the glacial behavior and test them against observations. Through our non-dimensionalization scheme, we construct a 2-D regime diagram, which allows a ready prognosis of the glacial properties over the full range of the external conditions, both climate- and size-related. We first discern the boundaries separating the glacial regimes of steady-creep, cyclic-surging and steady-sliding. We then apply the regime diagram to observed glaciers for quantitative comparisons. These include the Svalbard glaciers of both normal and surge types, Northeast Greenland Ice Stream characterized by steady-sliding, and Hudson Strait Ice Stream exhibiting cyclic surges. The quantitative validation of our model containing no free parameters suggests that the thermal switch may unify the dynamics of these diverse glaciers.