The Science of Climate Change at Siple Dome, West Antarctica

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The Science of Climate Change at Siple Dome, West
Antarctica
NASA-Goddard Space Flight Center Scientific
Visualization Studio
bo_at_u.washington.edu

• Bob Hawley, University of Washington
• Poulsbo TEA workshop- 11 Oct 2003

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Why West Antarctica?
Florida
Southeast asia
Figures Bob Bindschadler
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Marine ice sheet
Figure Howard Conway
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Ice streams
From http//igloo.gsfc.nasa.gov/wais/ismap2.jpg
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Retreat since LGM
From R. Bindschadler
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Grounding line retreat
From Conway et al, 1999
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Why Siple Dome?

• First of 2 WAISCORES cores
• Coast vs inland-spatial gradients
• Ice divide- simpler ice flow pattern

From http//waiscores.dri.edu
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Elements of a BIG project
Many disciplines involved
On the core
At the site

• Chemistry
• - isotopes
• - dust
• - ash
• Electrical properties
• Physical properties

• Ice flow modelling
• Near-surface firn processes
• Passive microwave sensing
• Snow-air transfer function

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Getting started
Surface strain measurements
Ice-penetrating radar
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Radar
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Ice coring operations
Image NICL
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Temperature logging- Borehole Paleothermometry
What can present temperatures tell us about past
temperatures?
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After 10 minutes
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After 1 hour
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Done!
Depth
Temperature
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Borehole thermometry
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Gisp2 T profile
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What is strain?
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Borehole Video
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Measuring Vertical Strain I
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Measuring Vertical Strain II
Caliper measurement
Photo Rolf Tremblay
Caliper measurement (mm)
Apparent radius (pixels)
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Borehole Optical Stratigraphy
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Making a simple Brightness profile
?
?
?
Image sequence
Depth Vs. Intensity
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Optical Stratigraphic Section
Depth (m)
Relative Intensity (arbitrary units)
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Nature of the features
Hawley et al., 2003
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Metamorphism / Deposition
Whats an annual layer anyway?
The Standard Model of firn stratification -
Alley 1988
5 cm
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Visual Stratigraphy
Annual layer counting Accumulation estimates
Photo Rolf Tremblay
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Annual layers
Hawley et al., 2003
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Annual layers continued
Hawley et al., 2003
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Large-scale variability
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Densification
Measurements (eg Fitzpatrick 1994,
Grootes et al. 1994) Modeling studies (eg
Alley 1987, Arnaud et al. 2000)
Depth (m)
Taylor Dome Firn profile From Fitzpatrick,
1994 And Grootes et al. 1994
Density (g/cm3)
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A little speculation
Siple Dome
Depth (m)
G. Lamorey pers. Comm.
Intensity (arbitrary units)
Density (g cm3)
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Back out to the broad picture
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Thanks!
Photo Sue Douglass