Analysis of the Antarctic Marginal Ice Zone based on unsupervised classification of standalone sea ice model data

Day, Noah S., Bennetts, Luke G., O’Farrell, Siobhan P., Alberello, Alberto ORCID: https://orcid.org/0000-0001-7957-4012 and Montiel, Fabien (2024) Analysis of the Antarctic Marginal Ice Zone based on unsupervised classification of standalone sea ice model data. Journal of Geophysical Research: Oceans, 129 (8). ISSN 2169-9275

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Abstract

The Antarctic marginal ice zone, the regularly wave-affected outer band of the sea ice covered Southern Ocean, typically contains an unconsolidated ice cover comprised of smaller, thinner floes than the inner ice pack. Thus, it is a highly dynamic region and susceptible to rapid expansion and contraction, making it a focal area for understanding and predicting the response of Antarctic sea ice to a changing climate. This novel study uses unsupervised statistical clustering of sea ice data simulated by a global sea ice model (standalone CICE6 combined with a wave propagation module and prescribed ocean) to address the outstanding challenge of separating the marginal ice zone from the inner ice pack in sea ice data sets. The method identifies a marginal ice zone with the desired characteristics and floe size is shown to be the key variable in the classification. Simulated marginal ice zone widths are similar to those derived from satellite observations of wave penetration distances, but contrast with those using the standard 15%–80% areal sea ice concentration proxy, particularly during austral winter. The simulated marginal ice zone is found to undergo a seasonal transition due to new ice formation in winter, increased drift in spring, and increased rates of wave-induced breakup and melting in summer. The understanding gained from the study motivates incorporation of wave and floe-scale processes in sea ice models, and the methods are available for application to outputs from high-resolution and coupled sea ice–ocean–wave models for more detailed studies of the marginal ice zone (in both hemispheres).

Item Type:	Article
Additional Information:	Data Availability Statement: CICE6 is an open source sea ice model and is available at: https://github.com/CICE-Consortium/CICE. The waves-in-ice module (WIM) used for this study along with the output data used to produce this manuscript are available at: https://zenodo.org/records/11081611 (Day et al., 2023). Statistical analysis was completed using Scikit-learn (version 1.1.3, available under the BSD-3-Clause license Pedregosa et al., 2011). The data wrangling and cleaning performed used Xarray (version 2022.11.0, available under the Apache-2.0 license Hoyer & Hamman, 2017) and Pandas (version 1.5.0, available under the BSD-3-Clause license Pandas development team, 2020). Figures were made using Matplotlib (version 3.4.3, license available at https://matplotlib.org/stable/users/project/license.html Hunter, 2007) and maps were created using Cartopy (version 0.20.2, available under the GNU GPLv3 license Met Office, 2010–2015). Funding information: Australian Research Council. Grant Numbers: DP200102828, FT190100404, LP200100406
Uncontrolled Keywords:	sea ice,ocean modeling,antarctica,machine learning,marginal ice zone,geochemistry and petrology,geophysics,oceanography,space and planetary science,earth and planetary sciences (miscellaneous),sdg 14 - life below water,sdg 13 - climate action ,/dk/atira/pure/subjectarea/asjc/1900/1906
Faculty \ School:	Faculty of Science > School of Engineering, Mathematics and Physics
UEA Research Groups:	Faculty of Science > Research Groups > Fluid and Solid Mechanics (former - to 2024) Faculty of Science > Research Groups > Fluids & Structures
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	27 Aug 2024 12:30
Last Modified:	07 Nov 2024 12:48
URI:	https://ueaeprints.uea.ac.uk/id/eprint/96350
DOI:	10.1029/2024JC020953

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