thanks so much for all the data: the amundsen sea sector data set: applications with umism: where...
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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?
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.
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*
Airborne Geophysical survey of the Amundsen Sea Embayment (Holt et al., 2006 & Vaughan et al., 2006)
Embedded ModelsEmbedded 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.
● 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: 9000 nodes, 10 km
Nested Grids: 10920 nodes, 5 km
Nested Grids: 6402 nodes, 5 km
Nested Grids: 9000 nodes, 10 km
Nested Grids: 10920 nodes, 5 km
Nested Grids: 6402 nodes, 5 km
Nested Grids: 10920 nodes, 5 km
Nested Grids: 6402 nodes, 5 km
Nested Grid: Summary & runtimes
Grid
Nodes
DeltaX
DeltaT
Steps
Time/step(s)
Time(hr)
A116263
40 10 4000
0.81 0.9
E1 9000
10 5 8000
0.80 1.8
F110920
5 140000
0.88 9.8
G1 6402
5 140000
0.54 6.0
Full36000
5 140000
2.9 (est) 32.0
Vostok Temperature Proxy
Area-growth and retreat
●
Volume-growth and retreat
●
Water Peak during retreat
●
Data (Rignot 2004) and Results
1
3
5
7
9
2
4
6
Data (Lang 2004) and Results
65
4
3
2
1
PIG: velocity
●
PIG: bed
●
PIG: thickness
●
PIG: water
●
PIG: velocity
●
Thwaites: velocity
●
Thwaites: bed
●
Thwaites: thickness
●
Thwaites: water
●
Thwaites: velocity
●
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
● See AGASEA:Velo● Requires bandwidth, movies are large…● http://tulip.umcs.maine
.edu/~shamis/iweb/WAIS-2006/AGASEA%3AVelo.html
Growth and retreat: water
● See AGASEA:Water● Requires bandwidth, movies are large…● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2
006/AGASEA%3AWater.html
Thwaites: thickness
● See Thwaites:Thick● Requires bandwidth, movies are large…● http://tulip.umcs.maine
.edu/~shamis/iweb/WAIS-2006/Thwaites%3AThick.html
Thwaites: velocity
● See Thwaites:Velo● Requires bandwidth, movies are large…● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-2
006/Thwaites%3AVelo.html
Thwaites: water
● See Thwaites:Water● Requires bandwidth, movies are large…● http://tulip.umcs.maine
.edu/~shamis/iweb/WAIS-2006/Thwaites%3AWater.html
PIG: Thickness
● See PIG:Thick● Requires bandwidth, movies are large…● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-
2006/PIG%3AThick.html
PIG: velocity
● See PIG:Velo● Requires bandwidth, movies are large…● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-
2006/PIG%3AVelo.html
PIG: water
● See PIG:Water● Requires bandwidth, movies are large…● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-
2006/PIG%3AWater.html
Future Retreat ScenariosFuture 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.
● 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
●
Future Retreat ScenariosFuture 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:
1. Condition is applied everywhere.
• Ross and Filchner-Ronne, as well as East Antarctica.
2. Condition is only applied in Amundsen Sea Sector.
• Two distinct patterns of retreat emerge for these two cases.
● 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:
1. Condition is applied everywhere.
• Ross and Filchner-Ronne, as well as East Antarctica.
2. Condition is only applied in Amundsen Sea Sector.
• Two distinct patterns of retreat emerge for these two cases.
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
● 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
● 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
● 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
● 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
● 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
●
1. Conclusions: Past cycle1. 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.
• 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 retreat2. 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.
• 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● Requires bandwidth, movies are large…● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS-
2006/Case 1%3ARate.html
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