Implementation of the Elasto-Brittle rheology for the ice pack simulations

Compared to classical sea ice models, two new variables, the sea ice damage and the internal stress tensor, are introduced. Another novelty is the element-based approach, for which the different fields are allowed to be highly discontinuous from one element to the other. The presence of these discontinuities requires specific implementations for the temporal and spatial discretization and for the advection and remeshing schemes. The time-stepping scheme combines explicit and implicit terms to preserve the symmetry of the system to be solved. The discretization is based on the finite element method. Using a Lagrangian instead of an Eulerian advection scheme is motivated by its better ability at transporting fields having discontinuities at the scale of the elements. The model produces realistic motion and deformation fields, exhibiting discontinuities and strong spatial localization of the deformation, as seen in reality. Two sets of initial conditions for sea ice concentration and thickness are used, one is only based on the TOPAZ reanalysis while the other one also takes into account estimates of the sea ice concentration and lead area fraction derived from the AMSR-E satellite.NERSC Technical Report no. 358. 'Sea ice model developments in view of oil spill forecasting' Deliverable 2.1. Funded by Oil and Gas Producers Contract no. JIP 28 10-1