Basal conditions and ice thickness on Pine Island Glacier

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Basal conditions and ice thickness on Pine Island
Glacier

• Andy Smith
• Julian Scott

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Objectives

• Seismic surveys what is beneath the ice
• GPS ice flow and variability
• Ice cores snow accumulation and history

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50 km
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Seismic reflection lines
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Seismic reflection lines
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Basal conditions Mixed Bed

• Wet sediments
• Sliding and deforming
• Comparable to Rutford Ice Stream
• Water
• Potential for less restraint?

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Ice thickness
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Ice thickness No change 1960 - 2006

• Thickness accuracy
• Position errors
• Position differences
• Preliminary indications 5-10 m

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Surface elevation (preliminary)

• 1960-2006
• Surface lowering 47 m
• Error estimate 25 m

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Speculation

• Recent thinning does not precede early 1990s
• 1974-87 acceleration restricted or ice
  thickening
• 1960-2006
• surface lowering, constant
  ice thickness
• erosion (0.51 m/a)