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• 1. [Article] Anisotropic Ice Flow Leading to the Onset of Ice Stream D, West Antarctica: Numerical Modelling Based on the Observations from Byrd Station Borehole

  An ice-sheet flowline model is used to simulate the flow of ice along two particle paths toward the onset to Ice Stream D,West Antarctica. One path is near the centre line of the main tributary to the ...

  Citation × Citation Citation Abstract Copy Title: Anisotropic Ice Flow Leading to the Onset of Ice Stream D, West Antarctica: Numerical Modelling Based on the Observations from Byrd Station Borehole Author: Wang, Weili, Zwally, H. Jay, Hulbe, Christina L., Siegert, Martin J., Joughin, Ian R. Year: 2003 An ice-sheet flowline model is used to simulate the flow of ice along two particle paths toward the onset to Ice Stream D,West Antarctica. One path is near the centre line of the main tributary to the ice stream, while the second passes by the Byrd Station borehole site. In this paper, we analyze the flow of the moderately fast-flowing tributaries in terms of ice-fabric anisotropy and estimate the steady-state ice-flow regions with the compatible developed crystal orientation fabrics along two particle paths. Comparison between modelled isochrones and internal layers detected from radio-echo sounding surveys in the area is used to suggest that flow upstream of the onset to Ice Stream D appears to have been stable since at least the Last Glacial Maximum. Title: Anisotropic Ice Flow Leading to the Onset of Ice Stream D, West Antarctica: Numerical Modelling Based on the Observations from Byrd Station Borehole Author: Wang, Weili, Zwally, H. Jay, Hulbe, Christina L., Siegert, Martin J., Joughin, Ian R. Year: 2003 An ice-sheet flowline model is used to simulate the flow of ice along two particle paths toward the onset to Ice Stream D,West Antarctica. One path is near the centre line of the main tributary to the ice stream, while the second passes by the Byrd Station borehole site. In this paper, we analyze the flow of the moderately fast-flowing tributaries in terms of ice-fabric anisotropy and estimate the steady-state ice-flow regions with the compatible developed crystal orientation fabrics along two particle paths. Comparison between modelled isochrones and internal layers detected from radio-echo sounding surveys in the area is used to suggest that flow upstream of the onset to Ice Stream D appears to have been stable since at least the Last Glacial Maximum. Close

• 2. [Article] Evaluation of strain rates on Ice Stream B, Antarctica, obtained using differential GPS

  The "stop-and-go" kinematic Global Positioning System (CPS) technique was used to survey 270 stations twice within a 25 km by 10 km strain grid on the surface of Ice Stream B. One or two geodetic quality ...

  Citation × Citation Citation Abstract Copy Title: Evaluation of strain rates on Ice Stream B, Antarctica, obtained using differential GPS Author: Hulbe, Christina L., Whillans, I. M. Year: 1994 The "stop-and-go" kinematic Global Positioning System (CPS) technique was used to survey 270 stations twice within a 25 km by 10 km strain grid on the surface of Ice Stream B. One or two geodetic quality receivers operated as reference pivots, while two similar receivers traveled to grid stations. Each station was occupied for 25 s. The method is rapid and reliable. Each survey was completed within 2 weeks. Calculated horizontal strain rates are accurate to 1%. Relative vertical velocities are accurate to 20 mm kmI a-1. Maps of the four horizontal velocity gradients, relative vertical velocity and surface elevation are presented. The vertical velocity pattern is used to identify the part of the topography that forms stationary waves and that which is migrating. No strong quantitative link is found between the pattern in horizontal strain rate and surface topography. In particular, there is no evidence that the topography is relaxing toward isostasy. None of the "weir-type" sticky spots, which are commonly observed with other glaciers, is found but there could be two of the "submerged-boulder type", which cause lateral flow diversion. Evidence for "hot stripes" and zones of preferred crystal orientation is not found. Title: Evaluation of strain rates on Ice Stream B, Antarctica, obtained using differential GPS Author: Hulbe, Christina L., Whillans, I. M. Year: 1994 The "stop-and-go" kinematic Global Positioning System (CPS) technique was used to survey 270 stations twice within a 25 km by 10 km strain grid on the surface of Ice Stream B. One or two geodetic quality receivers operated as reference pivots, while two similar receivers traveled to grid stations. Each station was occupied for 25 s. The method is rapid and reliable. Each survey was completed within 2 weeks. Calculated horizontal strain rates are accurate to 1%. Relative vertical velocities are accurate to 20 mm kmI a-1. Maps of the four horizontal velocity gradients, relative vertical velocity and surface elevation are presented. The vertical velocity pattern is used to identify the part of the topography that forms stationary waves and that which is migrating. No strong quantitative link is found between the pattern in horizontal strain rate and surface topography. In particular, there is no evidence that the topography is relaxing toward isostasy. None of the "weir-type" sticky spots, which are commonly observed with other glaciers, is found but there could be two of the "submerged-boulder type", which cause lateral flow diversion. Evidence for "hot stripes" and zones of preferred crystal orientation is not found. Close