Implications of Ocean Swell Fracturing of Perennial Pack Ice in the Southern Beaufort Sea

The Arctic summer minimum sea ice extent has been in decline for the past 30 years, with an extreme minimum extent of 4.2x106 sq/km in 2007. The greatest declines are observed in the Siberian, Laptev, Chukchi, and Beaufort seas, and the resulting large, contiguous expanse of open water represents the emergence of large wave-generation fetch distances in the Arctic Basin. Increases in the amplitude, and wavelength of storm swells coupled with decreasing ice thickness and extent may result in waves reaching the thick multi-year (MY) ice that builds against the Canadian Arctic Archipelago. Long waves can propagate under sea ice, deep into the pack, thereby causing flexural swell and failure within the sea ice cover. This process shifts the distribution of ice floes towards smaller diameters, increases ice floe surface area and ice floe mobility, and thereby affects sea ice dynamics and thermodynamic processes. This study presents a modelling study to investigate the thermodynamic and dynamic implications of flexural fracturing of perennial pack ice. Lateral melt rates are assessed by estimating the change in energy entrainment from longwave and solar radiation in the mixed-layer of the ocean, as well as from ocean heat fluxes. The impact of this process in future sea ice melt seasons is assessed by estimating the impacts of this process occurring earlier in the melt season. We then discuss the implications for sea ice dynamic processes during sea ice formation in the autumn / winter seasons.