1. 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.

2. BEDMAP vs AGASEA/BBAS* ★ Airborne Geophysical survey of the Amundsen Sea Embayment (Holt et al., 2006 & Vaughan et al., 2006)

3. 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. ● 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.

4. Nested Grids: 16263 nodes, 40 km

5. Nested Grids: 9000 nodes, 10 km

6. Nested Grids: 10920 nodes, 5 km

7. Nested Grids: 6402 nodes, 5 km

8. Nested Grids: 9000 nodes, 10 km

9. Nested Grids: 10920 nodes, 5 km

10. Nested Grids: 6402 nodes, 5 km

11. Nested Grids: 10920 nodes, 5 km

12. Nested Grids: 6402 nodes, 5 km

13. Nested Grid: Summary & runtimes GridNodesDeltaXDeltaTSteps Time/step (s) Time (hr) A116263 40 10 40000.810.9 E1 9000 10 5 80000.801.8 F110920 5 1400000.889.8 G1 6402 5 1400000.546.0 Full36000 5 1400002.9 (est)32.0

14. Vostok Temperature Proxy

15. Area-growth and retreat ●

16. Volume-growth and retreat ●

17. Water Peak during retreat ●

18. Data (Rignot 2004) and Results 1 3 5 7 9 2 4 6

19. Data (Lang 2004) and Results 6 5 4 3 2 1

20. PIG: velocity ●

21. PIG: bed ●

22. PIG: thickness ●

23. PIG: water ●

24. PIG: velocity ●

25. Thwaites: velocity ●

26. Thwaites: bed ●

27. Thwaites: thickness ●

28. Thwaites: water ●

29. Thwaites: velocity ●

30. Growth and retreat: thickness ● See AGASEA:Thick ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/AGASEA%3AThick.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/AGASEA%3AThick.html

31. Growth and retreat: velocity ● See AGASEA:Velo ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/AGASEA%3AVelo.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/AGASEA%3AVelo.html

32. Growth and retreat: water ● See AGASEA:Water ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/AGASEA%3AWater.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/AGASEA%3AWater.html

33. Thwaites: thickness ● See Thwaites:Thick ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/Thwaites%3AThick.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/Thwaites%3AThick.html

34. Thwaites: velocity ● See Thwaites:Velo ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/Thwaites%3AVelo.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/Thwaites%3AVelo.html

35. Thwaites: water ● See Thwaites:Water ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/Thwaites%3AWater.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/Thwaites%3AWater.html

36. PIG: Thickness ● See PIG:Thick ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/PIG%3AThick.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/PIG%3AThick.html

37. PIG: velocity ● See PIG:Velo ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/PIG%3AVelo.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/PIG%3AVelo.html

38. PIG: water ● See PIG:Water ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/PIG%3AWater.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/PIG%3AWater.html

39. 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. ● 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.

40. Weertman Parameter ●

41. 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: 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.

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

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

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

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

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

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

48. Future: water percent & volume ●

49. 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. 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.

50. 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. 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.

51. Case 1: Rate ● Case 1:Rate ● Requires bandwidth, movies are large… ● http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/Case 1%3ARate.html http://tulip.umcs.maine.edu/~shamis/iweb/WAIS- 2006/Case 1%3ARate.html

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