On Fri, 10 Aug 2007, Eric Swanson wrote: >> 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.
The common model used in GCMs is viscous plastic (or more primitive). Or the more modern elastic-viscous-plastic, which is supposedly scientifically equivalent (look up Hunke). Elastic-plastic is rather different and certainly not used in GCMs. On the resistance to motion, is doesnt matter a great deal how thick it is, in the sense that acceleration can usually be neglected. But clearly it affects its resistance to compression or shear (but the pure tensile strength remains negligible). -W. William M Connolley | [EMAIL PROTECTED] | http://www.antarctica.ac.uk/met/wmc/ Climate Modeller, British Antarctic Survey | 07985 935400 -- This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
