A simplified multi-scale model for predicting climatic variations of the ice-sheet surface elevation in central Antarctica
The equation describing the surface evolution of a large ice sheet is examined on the basis of a scale analysis applied to Antarctic conditions. Changes in the surface elevation are mainly driven by mass-balance fluctuations which approximately follow global atmospheric temperature variations. The e...
| Main Authors: | , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
1996
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| Subjects: | |
| Online Access: | http://dspace.kpfu.ru/xmlui/handle/net/95701 |
| Summary: | The equation describing the surface evolution of a large ice sheet is examined on the basis of a scale analysis applied to Antarctic conditions. Changes in the surface elevation are mainly driven by mass-balance fluctuations which approximately follow global atmospheric temperature variations. The essential spatial non-uniformity of the accumulation rate and the resultant difference between central and coastal regions in reaction time-scales are taken into account. The dynamic interaction of the time-lagging interior with the quasi-stationary margin is described. As a result, a simplified model is deduced to simulate the surface-elevation variations in the central parts of the Antarctic ice sheet caused by mass-balance perturbations corresponding to the main Milankovich cycles with the periods of 19-100 kyears. Special computational tests are performed to validate the model through inter-comparison with the predictions obtained with a two-dimensional thermomechanical model. The sensitivity of the model to physical factors (represented by dimensionless tuning parameters) is discussed. Climatically controlled variations of the ice-sheet thickness in the vicinity of Vostok Station during the past 200 kyears are estimated. |
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