Abstract

Landfast ice is nearly immobile sea ice attached to the coast. Despite the important role of landfast ice in coastal climates, landfast ice is not well simulated in current sea ice models and needs to be parameterized. The mechanism for landfast ice formation is linked to the local geography. Grounded ice ridges act as anchoring points in shallow water. Sea ice arching between offshore island chains can lead to landfast ice in deep water. Previous studies successfully represented landfast ice in shallow marginal seas using bathymetry information to implement a grounding scheme, but this method fails in deep regions. This paper develops a new parameterization for coarse resolution sea ice models using lateral drag as a function of sea ice thickness, drift velocity, and coastline length. The new parameterization is tested in a 36 km pan-Arctic sea ice-ocean simulation. The simulated landfast ice in the model run is compared to observations from satellite data. With the lateral drag parameterization, representation of landfast ice improves in deep marginal seas. The combination of the lateral drag parameterization and a grounding scheme leads to a realistic landfast ice distribution in most Arctic regions.