Models for polythermal ice sheets and glaciers

Polythermal ice sheets and glaciers contain both cold ice and temperate ice. We present two new models to describe the temperature and water content of such ice masses, accounting for the possibility of gravity- and pressure-driven water drainage according to Darcy's law. Both models are based...

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Bibliographic Details
Published in:The Cryosphere
Main Authors: I. J. Hewitt, C. Schoof
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2017
Subjects:
Online Access:https://doi.org/10.5194/tc-11-541-2017
https://doaj.org/article/1648a1c508d5432b867a519586c8e383
Description
Summary:Polythermal ice sheets and glaciers contain both cold ice and temperate ice. We present two new models to describe the temperature and water content of such ice masses, accounting for the possibility of gravity- and pressure-driven water drainage according to Darcy's law. Both models are based on the principle of energy conservation; one additionally invokes the theory of viscous compaction to calculate pore water pressure, and the other involves a modification of existing enthalpy gradient methods to include gravity-driven drainage. The models self-consistently predict the evolution of temperature in cold ice and of water content in temperate ice. Numerical solutions are described, and a number of illustrative test problems are presented, allowing comparison with existing methods. The suggested models are simple enough to be incorporated in existing ice-sheet models with little modification.