Title: Arctic Sea Ice Mechanics Speaker: Kara Peterson, University of New Mexico Date/Time: April 12, 2010 at 8:00-9:00am Location: CSRI Building/Room 90 (Sandia NM) Brief Abstract: Arctic sea ice plays an important role in global climate by reflecting a significant portion of the incoming solar radiation and limiting heat transfer between the atmosphere and ocean. Ac- curately predicting the future behavior of Arctic sea ice requires high-fidelity codes that combine complex physical models for the melt and growth of ice due to radiative forcing and the motion and deformation of ice due to ocean current and wind forcing. Current state-of-the-art sea ice codes, however, have limitations for the task of high-resolution modeling. One limitation is the use of an isotropic constitutive relation. For calculations with resolutions on the order of hundreds of kilometers an assumption of isotropy is reasonable since the cracks and ridges that are ubiquitous in the pack ice are distributed randomly over this scale. However, at higher resolutions a region may be dominated by a large crack that causes the response to be anisotropic. In addition, the Eulerian numerical methods generally used to solve the sea ice dynamics equations introduce artificial diffusion and dispersion resulting in smearing of the ice edge. To address these limitations we are using the Material-Point Method (MPM), which naturally discretizes the advective term in the dynamics equations through the use of Lagrangian particles. Additionally, we are continuing the development of an elastic-decohesive constitutive model, which explicitly includes displacement discontinuities or cracks and is solved at particle locations in MPM. Pan-Arctic simulations using MPM and the elastic-decohesive model are being completed for comparison with results from the Los Alamos National Laboratory CICE code, which is a state-of-the-art model that uses an elastic-viscous-plastic constitutive relation and a linear remapping method for advection. CSRI POC: Jim Strickland, 844-8421 |