Modeling Landfast Sea Ice by Adding Tensile Strength

摘要

Landfast ice is sea ice that forms and remains fixed along a coast, where it is either attached to the shore or held between shoals or grounded icebergs. The current generation of sea ice models is not capable of reproducing certain aspects of landfast ice behavior, for example the persistence of landfast sea ice under the effect of offshore winds. The authors develop a landfast sea ice model by adding tensile strength to the viscous-plastic as well as two versions of the elastic-viscous-plastic sea ice rheologies. One-dimensional implementations of these rheologies are used to explore the ability of coastal sea ice to resist offshore winds over extended times. While all modified rheologies are capable of maintaining landfast ice-like structures in the model, only the viscous-plastic rhcology fulfills theoretical expectations. The elastic-viscous-plaslic rheologies show initial elastic waves that weaken the ice and thus reduce its capacity of maintaining landfast ice. Further, special care has to be taken when implementing the most commonly used version of the elastic-viscous-plastic rheology because the standard set of parameters is not adequate for landfast sea ice modeling.