Case studies on the parameterization schemes of sea ice fragmentation for ocean waves

Abstract

Sea ice on the Southern Ocean has large seasonal variations. Floe size distribution has an important influence on the dynamic and thermodynamic processes of sea ice in the region with large seasonal variation and the Marginal Ice Zone. In the work, we introduced a prognostic floe size distribution (FSD) into a sea ice model and improved the calculation of lateral melt of sea ice. On this basis, we implemented two schemes of sea ice fragmentation for ocean waves and performed case studies on the effects of swell fracture on Antarctic sea ice variations. From the studies, we show it that the two schemes of sea ice fragmentation have unique characteristics in the mass transfer of sea ice among the floe size categories; if the break-up of ice floe is neglected, the effect of the improvement in lateral melt rate calculation on sea ice simulation is not significant; the simulated patterns of reduced sea ice concentration in March because of the effects of sea ice fragmentation and modification in calculation of lateral melt rate are similar since the two schemes of sea ice fragmentation both have close connections with sea ice thickness; the simulated sea ice area fraction for individual floe size categories varies with sea ice fragmentation schemes; this is due to their difference in characteristics of sea ice mass transfer among the floe size categories.