22 / 2026-05-09 19:04:34

The coupled Southern Ocean–Sea ice–Ice shelf Model (SOSIM v1.0): configuration and evaluation

Session 60 - Polar Ice Sheet-Shelf-Ocean Processes, Changes, and Sea Level Implications

Complex interactions among the ocean, sea ice, and ice shelves in the Southern Ocean are critical for global climate, yet accurately simulating these processes remains challenging in climate models, such as those participating in the Coupled Model Intercomparison Project Phase 6, due to their coarse resolution and incomplete physical components. Therefore, the development of high-resolution circumpolar coupled ocean–sea ice–ice shelf models could improve our understanding of the evolution of the Southern Ocean. In this study, we use the c66m version of the Massachusetts Institute of Technology General Circulation Model, including a sea ice component and an ice shelf component, to configure the coupled Southern Ocean–Sea ice–Ice shelf Model (SOSIM v1.0). Adopting the Refined Topography dataset version 2 for the geometry of seafloor and ice draft, SOSIM features a horizontal resolution of ~5 km and 70 vertical layers. Forced by the European Centre for Medium-Range Weather Forecasts Reanalysis v5, a long-term integration of SOSIM is run forward from 1979 to 2022, with daily outputs for estimating the oceanic state, sea ice evolution, and basal mass balance of ice shelves. A comprehensive evaluation of the performance of SOSIM has been conducted against multiple observational and reanalysis datasets. Identified biases include an underestimated Antarctic Circumpolar Current transport, an overestimated Antarctic Slope Current, a warm drift in abyssal waters, an exaggerated seasonality of sea ice extent, and an underestimated total ice shelf mass loss. Despite these limitations, SOSIM still captures large-scale hydrographic structures, the annual variability of sea ice, and cross-slope exchanges over shelf seas. Furthermore, SOSIM is set to serve as the dynamical core for the next-generation Southern Ocean Ice Prediction System being developed in China.