British Antarctic Survey.
Scientific Background The Antarctic ice sheet is the largest ice mass on the planet by an order of magnitude. It has the potential to contribute up to ~70 m to sea level rise. Small changes in mass balance will have an important and substantial impact on global sea level and Southern Ocean freshwate...
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| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.552.54 http://www.lists.reading.ac.uk/archives/met-jobs/2008-01/pdfFCIa1ZJelW.pdf |
| Summary: | Scientific Background The Antarctic ice sheet is the largest ice mass on the planet by an order of magnitude. It has the potential to contribute up to ~70 m to sea level rise. Small changes in mass balance will have an important and substantial impact on global sea level and Southern Ocean freshwater budget and circulation. Such changes may be due to variations in accumulation at the surface but also to changes in ice dynamics. Understanding the flow behaviour of the ice sheet is essential, therefore, to our knowledge of how it will behave in the future. In the last ~decade (primarily since the launch of ERS-1 in 1991) there has been a revolution in the accuracy, spatial and temporal resolution of observations and estimates of ice motion (Bamber et al. 2000; Joughin et al. 2002). From these observations we have discovered that the spatial pattern of ice flow is far more complex than was previously believed and enhanced flow features extend deep into the interior of the ice sheet (Figure 1). The reason for the location, intensity and stability of these enhanced flow features is, however, unclear. They are, in general, related to bedrock troughs that channel flow (e.g. Rippin et al. 2004) but the controls on their existence and extent are not obvious. A key question is the role and importance of subglacial hydrology and basal conditions on the development of enhanced flow features and also whether variations in ice viscosity are important. Fig 1. A plot of an estimate of the steady-state velocity field of the Antarctic ice sheet derived from surface topography, ice thickness and accumulation data (Bamber et al. 2000). |
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