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

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Case studies on the parameterization schemes of sea ice fragmentation for ocean waves Xiying Liu 1,2

&

Guanghong Liao 1,2 & Chenchen Lu 3

Received: 10 November 2019 / Accepted: 24 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020

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. Keywords Swell fracture . Numerical modeling . Floe size distribution . Sea ice . Antarctic

1 Introduction Climate change is a major crisis and severe challenge facing mankind and has become the focus of common concerns of countries around the world. Sea ice is not only a component of the climate system but also an indicator of climate change. Its change is one of the most important factors affecting the prediction of climate change (Laxon et al. 2003). Under the background of global warming, both the sea ice concentration and the duration of sea ice coverage experience rapid change Responsible Editor: Fanghua Xu This article is part of the Topical Collection on the 11th International Workshop on Modeling the Ocean (IWMO), Wuxi, China, 17-20 June 2019 * Xiying Liu [email protected] 1

Key Laboratory of Ministry of Education for Coastal Disaster and Protection, Hohai University, Nanjing 210024, China

2

College of Oceanography, Hohai University, Nanjing 210098, China

3

College of Meteorology and Oceanography, National University of Defence Technology, Nanjing 211101, China

(Stammerjohn et al. 2012; Lang et al. 2017). Studies suggest that the floe size distribution (FSD) of sea ice is a potential factor controlling the change rate of sea ice on a global scale (Toyota et al. 2016). In marginal ice zone (MIZ, referring to the boundary between the open sea and the region covered by sea ice. In MIZ, the dyn