On the surging potential of polar ice streams: Antarctic surges: A clear and present danger
Antarctic ice streams typically move hundreds of meters in a year. This investigation was carried out to determine whether polar ice streams can accelerate their motion from time to time by one or two orders of magnitude in the span of a few years, with appreciable effects on global sea level. The m...
| Main Authors: | , , |
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| Language: | unknown |
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2021
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| Subjects: | |
| Online Access: | http://www.osti.gov/servlets/purl/6020207 https://www.osti.gov/biblio/6020207 https://doi.org/10.2172/6020207 |
| Summary: | Antarctic ice streams typically move hundreds of meters in a year. This investigation was carried out to determine whether polar ice streams can accelerate their motion from time to time by one or two orders of magnitude in the span of a few years, with appreciable effects on global sea level. The mass gains and losses of the Antarctic ice sheet as a whole closely balance one another. Three-dimensional steady-state fields of ice velocity and temperature in broad agreement with the as yet very scant observational record for the ice sheet. A numerical model which links the sliding motion of the ice to the energy dissipated by the friction between the ice and the underlying rock, was used to simulate the time-dependent behavior of eight ice streams representing the full range of Antarctic conditions. In contrast to the realistic alternation between fast advances and stagnating retreats which the model had produced for some mountain glaciers known to surge, the modeled ice streams instead went from steady to irregular continuous fast sliding when the prescribed ice deformability was reduced and/or the implied lubrication by frictional heating was increased. Substantial rapid advances did not develop, except as transient phases in two experiments. The inability of the model in general to create surges in ice streams could be due solely to its over-simplified treatment of the complex hydraulic processes taking place below the ice. More adequate treatments of these processes are being developed and, when expanded into new self-propelled models, could show ice stream surges to be feasible. |
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