Ice stream Research Papers - Academia.edu (original) (raw)

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- Physical Geography, Earth Sciences, Geology, Geophysics
- by Olav Lian
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- Geology, Earth Surface Processes, Ice stream
- by Jonathan Bamber
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- Remote Sensing, Multidisciplinary, Topography, Volume

- by Doug Mair
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- Cartography, Glaciology, Synthetic Aperture Radar, Iceberg
- by Hester Jiskoot
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- Remote Sensing, Image Analysis, Comparative Study, Multidisciplinary
- by Hester Jiskoot
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- Remote Sensing, Image Analysis, Comparative Study, Multidisciplinary
- by Bernd Kulessa
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- Glaciology, Hydrogeology, Sensitivity Analysis, Uncertainty

The surface velocity field of Devon Ice Cap, Nunavut, Canada, was mapped using interferometric synthetic aperture radar (InSAR). Ascending European Remote-sensing Satellite 1 and 2 (ERS-1/-2) tandem mode data were used for the western and southeast sectors, and 3 day repeat pass ERS-1 imagery for the northeast sector. Speckle-tracking procedures were used with RADARSAT 1 imagery to obtain surface velocities over the terminus of Belcher Glacier (a major calving front) where decorrelation between ERS data occurred. The InSAR data highlight a significant contrast in ice-flow dynamics between the east and west sides of the ice cap. Ice movement west of the main north south divide is dominated by relatively uniform 'sheet' flow, but three fast-flowing outlet glaciers that extend 14 23 km beyond the ice-cap margin also drain this region. Several outlet glaciers that extend up to 60 km inland from the eastern margin drain the eastern side of the ice cap. The dominant ice-flow regimes were classified based on the relationship between the driving stress (averaged over a length scale of ten ice thicknesses) and the ratio of surface velocity to ice thickness. The mapped distribution of flow regimes appears to depict the spatial extent of basal sliding across the ice cap. This is supported by a close relationship between the occurrence of flow stripes on the ice surface and flow regimes where basal sliding was found to be an important component of the glacier motion. Iceberg calving rates were computed using measured surface velocities and ice thicknesses derived from airborne radio-echo sounding. The volume of ice calved between 1960 and 1999 was estimated to be 20.5 ± 4.7 km3 (or 0.57 km3 a-1). Approximately 89% of this loss occurred along the eastern margin. The largest single source is Belcher Glacier, which accounts for ˜50% of the total amount of ice calved.

- by David Burgess
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- Cartography, Glaciology, Synthetic Aperture Radar, Iceberg
- by S. Tulaczyk
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- Geology, Earth Surface Processes, Ice stream
- by Hermann Engelhardt
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- Glaciology, Borehole, Ice stream, SLIP
- by Daniela Accettella
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- Earth Sciences, Climate Change, Marine Geology, Climate variability
- by Christian Vincent
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- Climate Change, Climate variability, Climate, Multidisciplinary
- by S. Tulaczyk
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- Water, Hydraulics, Nonlinear dynamics, Theory
- by Ilker Fer
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- Oceanography, Microstructure, Turbulence, Heat Transfer
- by Emmanuel Le Meur
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- Climate Change, Climate variability, Climate, Multidisciplinary

Evans Ice Stream, West Antarctica, has five tributaries and a complex grounding zone. The grounding zone of Evans Ice Stream, between the landward and seaward limits of tidal flexing, was mapped using SAR interferometry. The width of the mapped grounding zone was compared with that derived from an elastic beam model, and the tidal height changes derived from interferometry were compared with the results of a tidal model. Results show that in 1994 and 1996 the Evans grounding zone was located up to 100 km upstream of its location in the BEDMAP dataset. The grounding line of Evans Ice Stream is subjected to 5 m vertical tidal forcing, which would clearly affect ice-stream flow.

- by Tavi Murray
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- Cartography, Geophysics, Modeling, Localization
- by Dana Floricioiu
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- Glaciology, Multidisciplinary, Glacier, Geophysical
- by Martin Siegert
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- Glaciology, Sea Level, Topography, Glaciers

Radio-echo sounding data are used to investigate bed roughness beneath the three enhanced-flow tributaries of Slessor Glacier, East Antarctica. Slow-moving inter-tributary areas are found to have rough beds, while the bed of the northernmost tributary is relatively smooth. A reconstruction of potential subglacial drainage routing indicates that water would be routed down this tributary, and investigations of basal topography following isostatic recovery reveal that the bed would have been below sea level in preglacial times, so marine sediments may have accumulated here. Together, these factors are further support for the dominance of basal motion in this tributary, reported elsewhere. Conversely, although the other two Slessor tributaries may have water routed beneath them, they would not have been below sea level before the growth of the ice sheet, so cannot be underlain by marine sediments. They are also found to be rough, and, within the range of uncertainties, it is likely that basal motion does not play a major role in the flow of these tributaries. Perhaps the most interesting area, however, is a deep trough where flow rates are currently low but the bed is as smooth as the northern Slessor trough. It is proposed that, although ice deformation currently dominates in this trough, basal motion may have occurred in the past, when the ice was thicker.

- by Jonathan Bamber
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- Glaciology, Sea Level, Topography, Glaciers
- by Jonathan Bamber
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- Remote Sensing, Finite element method, Multidisciplinary, Interferometry
- by David Rippin
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- Glaciology, Sea Level, Topography, Glaciers
- by Maarit Middleton
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- Geology, Flute, Younger Dryas, Sedimentary Geology