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Thanks SO Much for ALL the Data: The Amundsen Sea Sector Data Set: Applications with UMISM: Where and How Much WATER? What WILL happen in the future?. James L Fastook University of Maine

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James L Fastook University of Maine

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James l fastook university of maine

Thanks SO Much for ALL the Data: The Amundsen Sea Sector Data Set: Applications with UMISM: Where and How Much WATER? What WILL happen in the future?

James L Fastook

University of Maine

We thank the NSF, which has supported the development of this model over many years through several different grants.


Bedmap vs agasea bbas

BEDMAP vs AGASEA/BBAS*

  • Airborne Geophysical survey of the Amundsen Sea Embayment (Holt et al., 2006 & Vaughan et al., 2006)


Embedded models

Embedded Models

  • High-resolution, limited domain

    • runs inside

  • Low-resolution, larger domain model.

  • Modeling the whole ice sheet allows margins to be internally generated.

    • No need to specify flux or ice thickness along a boundary transecting an ice sheet.

  • Specification of appropriate Boundary Conditions for limited-domain model, based on spatial and temporal interpolations of larger-domain model.


Nested grids 16263 nodes 40 km

Nested Grids: 16263 nodes, 40 km


Nested grids 9000 nodes 10 km

Nested Grids: 9000 nodes, 10 km


Nested grids 10920 nodes 5 km

Nested Grids: 10920 nodes, 5 km


Nested grids 6402 nodes 5 km

Nested Grids: 6402 nodes, 5 km


Nested grids 9000 nodes 10 km1

Nested Grids: 9000 nodes, 10 km


Nested grids 10920 nodes 5 km1

Nested Grids: 10920 nodes, 5 km


Nested grids 6402 nodes 5 km1

Nested Grids: 6402 nodes, 5 km


Nested grids 10920 nodes 5 km2

Nested Grids: 10920 nodes, 5 km


Nested grids 6402 nodes 5 km2

Nested Grids: 6402 nodes, 5 km


Nested grid summary runtimes

Nested Grid: Summary & runtimes


Vostok temperature proxy

Vostok Temperature Proxy


Area growth and retreat

Area-growth and retreat


Volume growth and retreat

Volume-growth and retreat


Water peak during retreat

Water Peak during retreat


Data rignot 2004 and results

2

1

4

3

6

5

7

9

Data (Rignot 2004) and Results


Data lang 2004 and results

1

2

3

4

5

6

Data (Lang 2004) and Results


Pig velocity

PIG: velocity


Pig bed

PIG: bed


Pig thickness

PIG: thickness


Pig water

PIG: water


Pig velocity1

PIG: velocity


Thwaites velocity

Thwaites: velocity


Thwaites bed

Thwaites: bed


Thwaites thickness

Thwaites: thickness


Thwaites water

Thwaites: water


Thwaites velocity1

Thwaites: velocity


Growth and retreat thickness

Growth and retreat: thickness

  • See AGASEA:Thick

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/AGASEA%3AThick.html


Growth and retreat velocity

Growth and retreat: velocity

  • See AGASEA:Velo

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/AGASEA%3AVelo.html


Growth and retreat water

Growth and retreat: water

  • See AGASEA:Water

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/AGASEA%3AWater.html


Thwaites thickness1

Thwaites: thickness

  • See Thwaites:Thick

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Thwaites%3AThick.html


Thwaites velocity2

Thwaites: velocity

  • See Thwaites:Velo

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Thwaites%3AVelo.html


Thwaites water1

Thwaites: water

  • See Thwaites:Water

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Thwaites%3AWater.html


Pig thickness1

PIG: Thickness

  • See PIG:Thick

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/PIG%3AThick.html


Pig velocity2

PIG: velocity

  • See PIG:Velo

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/PIG%3AVelo.html


Pig water1

PIG: water

  • See PIG:Water

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/PIG%3AWater.html


Future retreat scenarios

Future Retreat Scenarios

  • Beginning with end of glacial cycle

    • Run 100 years with conditions that produced present grounding line position.

    • Then 1900 years with 1.00 Weertman thinning at grounding line wherever the bed is below 550 m.


Weertman parameter

Weertman Parameter


Future retreat scenarios1

Future Retreat Scenarios

  • Beginning with end of glacial cycle

    • Run 100 years with conditions that produced present grounding line position.

    • Then 1900 years with 1.00 Weertman thinning at grounding line wherever the bed is below 550 m.

  • Two Cases:

    • Condition is applied everywhere.

      • Ross and Filchner-Ronne, as well as East Antarctica.

    • Condition is only applied in Amundsen Sea Sector.

  • Two distinct patterns of retreat emerge for these two cases.


Case 1 thickness

Case 1: thickness

  • See Case 1:Thick

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Case 1%3AThick.html


Case 1 velocity

Case 1: velocity

  • See Case 1:Velo

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Case 1%3AVelo.html


Case 1 water

Case 1: water

  • See Case 1:Water

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Case 1%3AWater.html


Case 2 thickness

Case 2: thickness

  • See Case 2:Thick

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Case 2%3AThick.html


Case 2 velocity

Case 2: velocity

  • See Case 2:Velo

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Case 2%3AVelo.html


Case 2 water

Case 2: water

  • See Case 2:Water

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Case 2%3AWater.html


Future water percent volume

Future: water percent & volume


1 conclusions past cycle

1. Conclusions: Past cycle

  • From a modeler’s perspective the new data set is great.

  • The nested, embedded model captures the salient features of the Amundsen Sea Sector velocity field.

  • The water system is

    • dendritic,

    • follows bed topography,

    • appears to be decreasing in area as the present is approached,

    • with peak water volumes during or just prior to periods of retreat.


2 conclusions future retreat

2. Conclusions: Future retreat

  • Retreat scenarios depend strongly on whether grounding-line thinning is confined to the Amundsen Sector (Case 2) or involve the Ross and Filchner-Ronne too (Case 1).

    • In Case 1, retreat is much faster and more extensive, and comes in from behind the Amundsen Sea Sector.

    • Case 2 looks more like the classic “weak underbelly” with retreat in Thwaites and up the PIG with a non-smooth episodic retreat punctuated by pulses of water production that seem to precede retreat steps.


Case 1 rate

Case 1: Rate

  • Case 1:Rate

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Case 1%3ARate.html


Case 2 rate

Case 2: Rate

  • See Case 2:Rate

  • Requires bandwidth, movies are large…

  • http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2006/Case 2%3ARate.html


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