A Hybrid Particle-Continuum Method for Simulating Fast Ice via Subgrid Iceberg Interaction

Fuente: arXiv
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Main Authors: Mehlmann, Carolin, Kahl, Saskia
Format: Preprint
Published: 2025
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author Mehlmann, Carolin
Kahl, Saskia
author_facet Mehlmann, Carolin
Kahl, Saskia
contents A significant fraction (4%-13%) of Antarctic sea ice remains stationary as landfast sea-ice ("fast ice"), typically anchored by grounded icebergs. Current global climate models do not represent fast-ice formation due to iceberg grounding, as iceberg-sea-ice interaction mostly occurs at subgrid scales. We propose a novel subgrid-scale coupling mechanism between Lagrangian iceberg particles and an Eulerian sea-ice continuum model. This hybrid particle-continuum approach integrates feedback from icebergs into the sea-ice momentum equation via a Green's function, a Stokeslet, representing the drag exerted by a point force on the viscous-plastic medium. The coupled system, including the Stokeslet induced drag, is discretized using a finite-element method with piecewise linear basis functions. The approach assumes that individual icebergs have diameters smaller than the grid spacing. The presented finite-element discretization is compatible with existing unstructured-mesh ocean model frameworks such as FESOM and ICON, ensuring practical applicability in Earth system modeling. This work provides and analyzes, for the first time, a stable numerical framework to capture the effects of individual subgrid-scale icebergs on sea-ice dynamics. We derive an a-priori stability estimate bounding a functional of the sea-ice system and show that the momentum equation including the subgrid iceberg-sea-ice drag remains stable. Numerical test cases demonstrate the capability of the approach to capture fast-ice formation due to subgrid iceberg grounding on coarse horizontal grids.
format Preprint
id arxiv_https___arxiv_org_abs_2507_20306
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Hybrid Particle-Continuum Method for Simulating Fast Ice via Subgrid Iceberg Interaction
Mehlmann, Carolin
Kahl, Saskia
Numerical Analysis
A significant fraction (4%-13%) of Antarctic sea ice remains stationary as landfast sea-ice ("fast ice"), typically anchored by grounded icebergs. Current global climate models do not represent fast-ice formation due to iceberg grounding, as iceberg-sea-ice interaction mostly occurs at subgrid scales. We propose a novel subgrid-scale coupling mechanism between Lagrangian iceberg particles and an Eulerian sea-ice continuum model. This hybrid particle-continuum approach integrates feedback from icebergs into the sea-ice momentum equation via a Green's function, a Stokeslet, representing the drag exerted by a point force on the viscous-plastic medium. The coupled system, including the Stokeslet induced drag, is discretized using a finite-element method with piecewise linear basis functions. The approach assumes that individual icebergs have diameters smaller than the grid spacing. The presented finite-element discretization is compatible with existing unstructured-mesh ocean model frameworks such as FESOM and ICON, ensuring practical applicability in Earth system modeling. This work provides and analyzes, for the first time, a stable numerical framework to capture the effects of individual subgrid-scale icebergs on sea-ice dynamics. We derive an a-priori stability estimate bounding a functional of the sea-ice system and show that the momentum equation including the subgrid iceberg-sea-ice drag remains stable. Numerical test cases demonstrate the capability of the approach to capture fast-ice formation due to subgrid iceberg grounding on coarse horizontal grids.
title A Hybrid Particle-Continuum Method for Simulating Fast Ice via Subgrid Iceberg Interaction
topic Numerical Analysis
url https://arxiv.org/abs/2507.20306