ABSTRACT: Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets.

CGRG Bibliography of Canadian Geomorphology
Search Results

Author :

Date :

Title :

Publication :

Issue :

Page(s) :

Abstract

By using a simple parameterized model of thermomechanically coupled flow in cold ice sheets, together with a physically based sliding law which includes a description of basal drainage, it is shown that relationships between ice flux and ice thickness can be multi-valued, and hence that hydraulically induced surges can occur. This mechanism is termed hydraulic run-away, as it relies on the positive feedback between sliding velocity and basal melt production. For this feedback to operate, it is essential that water pressure increases with water storage. This is consistent with various recent ideas concerning drainage under ice sheets, be it through a system of canals, a distributed film or a subglacial aquifer. For confined flows, such as valley glaciers (e.g. Trapridge Glacier) or topographically constrained ice streams (e.g. Hudson Strait in the Laurentide ice sheet), which are underlain by sufficiently deformable sediment, thermally regulated surges are expected, while in a laterally unconfined drainage basin (such as that which flows into the Ross Ice Shelf), ice streams may develop. (Auth. mod.)

Bibliography of Canadian Geomorphology