open access

https://hdl.handle.net/2115/47917

Polythermal modelling of steady states of the Antarctic ice sheet in comparison with the real world

英語

1996

International Glaciological Society

Annals of Glaciology

23

382-387

An approach to simulate the present Antarctic ice sheet with respect to its thermomechanical behaviour and the resulting features is made with the three-dimensional polythermal ice-sheet model designed by Greve and Hutter. It treats zones of cold and temperate ice as different materials with their own properties and dynamics. This is important becausc an underlying layer of temperate ice can influence the ice sheet as a whole, e.g. the cold ice may slide upon the less viscous binary ice-water mixture. Measurements indicate that the geothermal heat flux below the Antarctic ice sheet appears to be remarkably higher than the standard value of 42mWm-2 that si usually applied for Precambrian shields in ice-sheet modelling. Since the extent of temperate ice at the base is highly dependent on this heat input from the lithosphere, an adequate choice is crucial for realistic simulations. We shall present a series of steady-state results with varied geothermal heat flux and demonstrate that the real ice-sheet, topography can be reproduced fairly well with a value in the range 50-60 mW m-2. Thus, the physical parameters of ice (especially the enhancement factor in Glen's flow law) as used by Greve (1995) for polythermal Greenland ice-sheet simulations can be adopted without any change. The remaining disagreements may be explained by the neglected influence of the ice shelves, the rather coarse horizontal resolution (100km), the steady-state assumption and possible shortcomings in the parameterization of the surface mass balance .

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© 1996 International Glaciological Society

0260-3055