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Abstract Large tabular icebergs account for the majority of ice mass calved from Antarctic ice shelves, but are omitted from climate models. Specifically, these models do not account for iceberg breakup and as a result, modeled large icebergs could drift to low latitudes. Here, we develop a physically based parameterization of iceberg breakup based on the “footloose mechanism” suitable for climate models. This mechanism describes breakup of ice pieces from the iceberg edges triggered by buoyancy forces associated with a submerged ice foot fringing the iceberg. This foot develops as a result of ocean‐induced melt and erosion of the iceberg freeboard explicitly parameterized in the model. We then use an elastic beam model to determine when the foot is large enough to trigger calving, as well as the size of each child iceberg, which is controlled with the ice stiffness parameter. We test the breakup parameterization with a realistic large iceberg calving‐size distribution in the Geophysical Fluid Dynamics Laboratory OM4 ocean/sea‐ice model and obtain simulated iceberg trajectories and areas that closely match observations. Thus, the footloose mechanism appears to play a major role in iceberg decay that was previously unaccounted for in iceberg models. We also find that varying the size of the broken ice bits can influence the iceberg meltwater distribution more than physically realistic variations to the footloose decay rate.
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This content will become publicly available on November 11, 2025
Collision with Seamount Triggers Breakup of Antarctic Iceberg
Abstract. Iceberg A68a calved from Larsen C ice shelf, experienced several major calving when drifting around the South Georgia Island in late 2020. Here, we show for the first time that the decisive factor for its calving was a collision with the surrounding seamount. By treating the iceberg as a deformable body in an established ice-flow model, we show how its collision with the seafloor created huge stresses within the iceberg that led to its disintegration. The drifting and rotating of the iceberg, while grounded, further enhanced its breakup. Moving over a grounded shoal increased the tensile stresses by a factor of almost one hundred more than immobile grounding alone, and rotational motion about the pinning point increased the stresses by another twenty percent. Modeling the fracture and breakup of a large tabular iceberg is an essential step toward better understanding the life cycle of an iceberg. The possible collapse of the marine-based sectors of the great ice sheets in a warming world may lead to a massive increase in the number of icebergs in the surrounding oceans. It will be crucial to be able to understand where such icebergs drift and how they ultimately disintegrate into the ocean.
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- Award ID(s):
- 2151295
- PAR ID:
- 10574095
- Publisher / Repository:
- EGUsphere
- Date Published:
- Format(s):
- Medium: X
- Institution:
- School of Oceanography, Shanghai Jiao Tong University
- Sponsoring Org:
- National Science Foundation
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