Models for polythermal ice sheets and glaciers

• Main Authors: Hewitt, I, Schoof, C
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: European Geosciences Union 2017
• Subjects: Ice Sheet
• Online Access: https://doi.org/10.5194/tc-2016-240; https://ora.ox.ac.uk/objects/uuid:9ffeb79d-18c6-472d-b1d9-c1325e6d42a4

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 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.