Altimetric observation of wave attenuation through the Antarctic marginal ice zone using ICESat-2

Brouwer, Jill, Fraser, Alexander D., Murphy, Damian J., Wongpan, Pat, Alberello, Alberto ORCID: https://orcid.org/0000-0001-7957-4012, Kohout, Alison, Horvat, Christopher, Wotherspoon, Simon, Massom, Robert A., Cartwright, Jessica and Williams, Guy D. (2022) Altimetric observation of wave attenuation through the Antarctic marginal ice zone using ICESat-2. The Cryosphere, 16 (6). 2325–2353. ISSN 1994-0440

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Abstract

The Antarctic marginal ice zone (MIZ) is a highly dynamic region where sea ice interacts with ocean surface waves generated in ice-free areas of the Southern Ocean. Improved large-scale (satellite-based) estimates of MIZ extent and variability are crucial for understanding atmosphere–ice–ocean interactions and biological processes and detection of change therein. Legacy methods for defining the MIZ are typically based on sea ice concentration thresholds and do not directly relate to the fundamental physical processes driving MIZ variability. To address this, new techniques have been developed to measure the spatial extent of significant wave height attenuation in sea ice from variations in Ice, Cloud and land Elevation Satellite-2 (ICESat-2) surface heights. The poleward wave penetration limit (boundary) is defined as the location where significant wave height attenuation equals the estimated error in significant wave height. Extensive automated and manual acceptance/rejection criteria are employed to ensure confidence in along-track wave penetration width estimates due to significant cloud contamination of ICESat-2 data or where wave attenuation is not observed. Analysis of 304 ICESat-2 tracks retrieved from four months of 2019 (February, May, September and December) reveals that sea-ice-concentration-derived MIZ width estimates are far narrower (by a factor of ∼ 7 on average) than those from the new technique presented here. These results suggest that indirect methods of MIZ estimation based on sea ice concentration are insufficient for representing physical processes that define the MIZ. Improved large-scale measurements of wave attenuation in the MIZ will play an important role in increasing our understanding of this complex sea ice zone.

Item Type: Article
Additional Information: Financial support: This project received grant funding from the Australian Government as part of the Antarctic Science Collaboration Initiative and contributes to Project 6 of the Australian Antarctic Program Partnership (project ID ASCI000002). This research was supported by use of the Nectar Research Cloud and by the Tasmanian Partnership for Advanced Computing. The Nectar Research Cloud is a collaborative Australian research platform supported by the NCRIS-funded Australian Research Data Commons (ARDC). Robert A. Massom is supported by the Australian Antarctic Division, the Australian Government’s Australian Antarctic Program Partnership and the Australian Research Council Special Research Initiative Australian Centre for Excellence in Antarctic Science (project number SR200100008), and this study contributes to AAS Project 4528. Alberto Alberello and Pat Wongpan were supported by the Japan Society for the Promotion of Science (PE19055 and 18F18794, respectively).
Uncontrolled Keywords: water science and technology,earth-surface processes,sdg 14 - life below water ,/dk/atira/pure/subjectarea/asjc/2300/2312
Faculty \ School: Faculty of Science > School of Mathematics
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Depositing User: LivePure Connector
Date Deposited: 24 Jun 2022 08:30
Last Modified: 12 Aug 2022 04:59
URI: https://ueaeprints.uea.ac.uk/id/eprint/85770
DOI: 10.5194/tc-16-2325-2022

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