William M Connolley wrote: > On Fri, 10 Aug 2007, Eric Swanson wrote: > > As the sea-ice extent declines, it's thickness also decreases. I > > think it's likely that the thickness will decline so much that there > > will be the chance of a mechanical failure, even before the extent > > could actually reaches zero. The result could look much like the > > breakup of the Larson B ice shelf along the Antarctic Peninsula, which > > was sudden and spectacular . > > This is unlikely. Sea ice has essentially no strength in tension anyway.
Looking about, I found some references to various models for sea-ice strength, i.e., rheology. An early modeling approach by Hibler used a viscous-plastic assumption, which has been used by some ocean model builders. There appear to be other models based on an elastic assumption, such as this one: David M. Holland, "A 1-D elastic-plastic sea-ice model solved with an implicit Eulerian-Lagrangian method", Ocean Modelling Volume 17, Issue 1, 2007, Pages 1-27 Either way, it would seem that the resistance to motion would be greater for thicker multi-year ice than for first year ice. It's the potential for an increase in motion that I think would be important. To begin with, if the sea-ice is no longer bound to fast ice along the coast lines, surely it would move faster. Here's a model study which uses an elastic-plastic model: http://efdl.cims.nyu.edu/publications/summer_students/mazover_landfast_05.pdf I think their point about the permanence of landfast ice is important, since we know it exists and isn't easily dislodged. This suggests that the tensile strength of sea-ice away from the coast may also be important. E. S. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/globalchange -~----------~----~----~----~------~----~------~--~---
