Sea ice covers the polar oceans extensively in winter, becoming contiguous with the Arctic coastline. It moves and deforms under the action of wind and ocean currents, and when there is a contiguous sheet of ice that ice can crack and deform, or flow along shear zones. Some have hypothesized that the model that describes this mechanical behavior of sea ice, the relationship between internal ice stress and strain-rate, can be applied across scales from meters to 1000s of kilometers. If this is the case, we would expect horizontal sea ice deformation to be scale invariant, and behave as a multi-fractal. Past studies find there is multi-fractal behavior for horizontal sea-ice deformation from 10 to 1000km.

In March and April 2021, buoys were deployed in the Beaufort Sea, Arctic Ocean, to measure sea-ice horizontal deformation over spatial scales that had not been previously achieved. Geodetic-quality position measurements allowed measurements of strain-rate over lengths from about 200m to 2km. Conventional ice-drifters extended spatial coverage up to about 100km. Our results demonstrate that such behavior does not hold when including spatial scales below 10km. We find that sea-ice deformation is not scale invariant between the scale of individual sea-ice floes and aggregates of floes. Therefore, we cannot expect the same physical laws or forcing to describe sea-ice kinematics over these regimes. This highlights the need to take a multi-scale approach in developing rheological models of sea ice.