Scaling of sea ice deformation and related feedbacks (Invited)

This talk presents results from ice drifting buoys that have been used to study self-similarity in sea ice drift and deformation from hours to months and 10 to 200 km. We have used multi-scale analysis techniques to understand scaling relationships in both strain rate and stress. These analysis techniques will allow quantitative multi-scale comparisons with output from sea ice mechanics models. It is necessary to separate out superimposed sea ice scaled responses: interactions with the ocean and atmosphere, and scales inherent in sea ice as an isolated material. Over the scales of synoptic weather systems and larger, pack ice deformation is coherent during winter. For smaller scales coherence between areas of ice is reduced, and deformation becomes a pink noise process as the lead scale is approached. This suggests that the precise location of particular leads and ridges may not be predictable. This characteristic of ice pack deformation impacts ice mass balance, ocean-atmosphere fluxes, and the kinetic energy budget of the ice pack. Unless lead scale deformation is resolved, ice mass balance and ocean-atmosphere fluxes will be under-estimated. We provide recommendations for observation system and model design, which depend on the scale of interest. For regional, seasonal studies course resolution may be reasonable, provided an adequate statistical representation of the ice pack divergence rate is made. Localized experiments that focus on particular deformation related processes require 10km and 3 hourly resolution, or higher. It is unknown whether the viscous-plastic sea ice model can correctly represent ice deformation properties on these scales. Several metrics are presented that may serve to answer this question using Earth System Models.