Flow dynamics of tidewater glaciers : a numerical modelling approach.

• Published in: Journal of Glaciology
• Main Authors: Vieli, A., Funk, M., Blatter, H.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: International Glaciological Society 2001
• Subjects: Southern Patagonia; Subglacial Water; Columbia Glacier; Hydrologic Basis; Rapid Motion; San-Rafael; Alaska; Switzerland; Stability; Pressure; Patagonia; glacier; glaciers; Journal of Glaciology; Tidewater
• Online Access: http://dro.dur.ac.uk/1234/; http://dro.dur.ac.uk/1234/1/1234.pdf; https://doi.org/10.3189/172756501781831747

The dynamics of grounded tidewater glaciers is investigated with a time-dependent numerical flow model, which solves the full equations for the stress and velocity fields and includes a water-pressure-dependent sliding law. The calving criterion implemented in the model shifts the calving front at each time-step to the position where the frontal ice thickness exceeds flotation height by a prescribed value. With this model, the linear relation between calving rate and water depth proposed on empirical grounds is qualitatively reproduced for the situation of a slowly retreating or advancing terminus, but not for situations of rapid changes. Length changes of tidewater glaciers, i.e.especially rapid changes, are dominantly controlled by the bed topography and are to a minor degree a direct reaction to a mass-balance change. Thus, accurate information on the near-terminus bed topography is required for reliable prediction of the terminus changes due to climate changes. The results also confirm the suggested cycles of slow advance and rapid retreat through a basal depression. Rapid changes in terminus positions preferably occur in places where the bed slopes upwards in the ice-flow direction.