What do Paleoclimate . records tell us about . WAIS stability?
What Do West Antarctic Ice Cores Say About Rapid Ice Flow?
Ken TaylorRichard AlleyEd BrookHoward Conway Jeff Severinghaus Paul Mayewski Jim White
Byrd vs SDM
White & Brook
Warmer
Colder
Byrd vs SDM
White & Brook
Warmer
Colder
Byrd vs SDM
White & Brook
15 ka
22 ka
Warmer
Colder
Byrd vs SDM
White & Brook
Warmer
Colder
Gas records
kkks
Must be local change at Siple Dome because:
1) Change does not show up at Byrd
2) Proxies of distant climate (Dexcess and chemistry) do not show significant changes
Siple Dome Records
Gas records
kkks
Must be local change at Siple Dome because:
1) Change does not show up at Byrd
2) Proxies of distant climate (Dexcess and chemistry) do not show significant changes
Siple Dome Records
Disrupted stratigraphy
Regional Climate Change:Would see something at Byrd and in other climate proxies from SDM.
Regional Climate Change:Would see something at Byrd and in other climate proxies from SDM.
Mishandling of Core: Gas record/Deuterium record offset is correct
Regional Climate Change:Would see something at Byrd and in other climate proxies from SDM.
Mishandling of Core: Gas record/Deuterium record offset is correct
Folded Stratigraphy:No suitable ice to fold into record
Regional Climate Change:Would see something at Byrd and in other climate proxies from SDM.
Mishandling of Core: Gas record/Deuterium record offset is correct
Folded Stratigraphy:No suitable ice to fold into record
Ice Flow Overrode Siple DomeChange in record is too abruptNo other ice with right characterisitics
Regional Climate Change:Would see something at Byrd and in other climate proxies from SDM.
Mishandling of Core: Gas record/Deuterium record offset is correct
Folded Stratigraphy:No suitable ice to fold into record
Ice Flow Overrode Siple DomeChange in record is too abrupt
Interpretation 1: Elevation of Siple Dome Changed Lapse Rate
22 ka B.P. 6oC warming, ~200 years 600 m elevation decrease at SDM
15 ka B.P.3.5oC warming < 1,000? years350 m elevation decrease at
SDM
Ice Flow Modeling: Rapid 350 m decrease of Siple Dome
at 15 ka (Price et. al., 2007)
Atmospheric Modeling: Elevation of ice streams has large influence on temperature at Summit of Siple Dome(Monaghan & Bromwich, 2006)
Interpretation 1: Elevation of Siple Dome Changed Lapse Rate
22 ka B.P. 6oC warming, ~200 years 600 m elevation decrease at SDM
15 ka B.P.3.5oC warming < 1,000? years350 m elevation decrease at
SDM
Ice Flow Modeling: Rapid 350 m decrease of Siple Dome
at 15 ka (Price et. al., 2007)
Atmospheric Modeling: Elevation of ice streams has large influence on temperature at Summit of Siple Dome(Monaghan & Bromwich, 2006)
Interpretation 2: Elevation of Ice Streams Changed Air Flow Changed
Atmospheric Modeling: Elevation of ice streams has large influence on temperature at Summit of Siple Dome (Monaghan & Bromwich, 2006)Ice Sheet Model: Siple Dome was a bump (Dave Pollard)
SDMSDM
BYRDBYRD
Current situation Paleo situation
Some combination of:1) Changes in SDM surface elevation . (lapse rate)
2) Changes in ice stream elevation . (air flow patterns/katabatic winds)
At 15 ka and 22 ka there were large and rapid drawn downs of ice on the Siple Coast.
What caused ice draw down?
Sea level rise
Sub-ice flood
Ice shelf collapse
Ice stream internal dynamics
• ocean Explaination
Siple: White et al
Sea Level
The Siple Dome events precede the step increases in sea level.
What caused ice draw down?
Sea level rise
Sub-ice flood
Ice shelf collapse
Ice stream internal dynamics
`Eastern Ross SeaMosola & Anderson, 2006
Slope Gullies
Sub-ice water system
What caused ice draw down?
Sea level rise
Sub-ice flood
Ice shelf collapse
Ice stream internal dynamics
• MAP SHOWING
• Tdome, SDM, BYRD, Moulton, OCEAM COres
Roosevelt Island
RossIce Shelf
Siple Dome
http://lima.usgs.gov/access.php
• MAP SHOWING
• Tdome, SDM, BYRD, Moulton, OCEAM COres
Roosevelt Island
RossIce Shelf
Siple Dome
http://lima.usgs.gov/access.php
Water Temperature
Ice ShelfThickness
Bathymetry Siple and ShiraseCoasts are most vulnerable
David Holland
Water Temperature
Ice ShelfThickness
Bathymetry Siple and ShiraseCoasts are most vulnerable
David Holland
Water Temperature
Ice ShelfThickness
Bathymetry Siple and ShiraseCoasts are most vulnerable
David Holland
Water Temperature
Ice ShelfThickness
Bathymetry Siple and ShiraseCoasts are most vulnerable
David Holland
`Eastern Ross SeaMosola & Anderson, 2006
Iceberg furrows at 650 mNo sub-ice shelf deposits
Rapid retreat of grounded ice
• MAP SHOWING
• Tdome, SDM, BYRD, Moulton, OCEAM COres
Roosevelt Island
RossIce Shelf
Siple Dome
http://lima.usgs.gov/access.php
What caused ice draw down?
Sea level rise
Sub-ice flood
Ice shelf collapse
Ice stream internal dynamics
Siple Coast ice had large and rapid changes at 15 ka and 22 ka
Basal floodingBreak up of a portion of the Ross Ice ShelfIce stream internal dynamics
Amanda Mosola & John Anderson
Andy Monaghan, Dave Brom
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