Small-scale deformation of an Arctic sea ice floe detected by GPS and satellite imagery

Small-scale (~100-200 m) deformations of an Arctic sea ice floe were detected from multiple GPS-equipped buoys that were deployed on the same ice floe. Over a nine-month period three deformation events were recorded. At each case the event was of limited duration, each lasting less than a day. The events were highly compressive in nature with the area occupied by the buoy array decreasing by over half of the original area. The strain rate during the deformation, of the order of 10^-5s^-1, is about three orders of magnitude larger than previous estimates for brittle fracturing for cracks of about 100m in length. On the 2 day time scale, the strain rate became too small and none of the deformation events could be detected. This suggests that satellite data with longer time scales may significantly underestimate the amount of intermittent, small-scale brittle failure of total deformation. Taken as a whole, our results show the influence that large-scale wind stress can have on small-scale deformation. However, it is important to note that the impact of large-scale wind stress is also dependent on the properties of sea ice as well as on the spatial and temporal evolution of the underlying forces that influence the fracturing process.