Sea ice rheologies for large-scale models

(eng) Current sea ice models are far from simulating the complex behavior of the Arctic ice pack. When used at high resolution, they do not provide realistic deformation fields that are responsible for sea ice ridging and leads opening. The impacts of using a better representation of sea ice dynamics may then be crucial for many applications related to sea ice and in particular for the accuracy of climate change predictions, not only in the Arctic but also at a much larger scale. In this thesis, we adopted a two-fold strategy. On the one hand, we started from a widely used sea ice model and we improved the accuracy and performances of the numerical methods used to solve sea ice dynamics. On the other hand, we adopted a completely new approach with the implementation of the elasto-brittle rheology that produces more realistic results. We adapted it for a better integration in classical sea ice models and we confirmed its ability to reproduce the complex behavior of the Arctic ice pack.