Large areas of polar and subpolar oceans are permanently or seasonally covered with sea ice.
At geophysical scales, continuum models provide established and computationally efficient tools for simulating sea ice dynamics and thermodynamics. However, there is growing evidence that smaller-scale processes, acting at the level of individual ice floes and at present not taken into account in sea ice models, may contribute to and substantially modify the larger-scale dynamics. At the scale of ice floes, sea ice can be treated as a granular material and modelled with discrete-element methods (DEM). In my talk, I will show examples of DEM applications to sea ice modelling, and discuss selected "granular" aspects of sea ice dynamics, with an emphasis on phenomena that are linked to extreme polydispersity often observed in sea ice (heavy-tailed floe-size distributions). Although the model has been designed to represent sea ice, the results provide new insights into the behaviour of other strongly polydisperse granular materials.