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Modeling intensive ocean-cryosphere interactions in Lützow-Holm Bay, East Antarctica

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Kusahara, K, Hirano, D, Fujii, M, Fraser, AD ORCID: 0000-0003-1924-0015 and Tamura, T 2021 , 'Modeling intensive ocean-cryosphere interactions in Lützow-Holm Bay, East Antarctica' , Cryosphere, vol. 15 , 1697–1717 , doi: 10.5194/tc-2020-240.

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Abstract

Basal melting of Antarctic ice shelves accounts for more than half of the mass loss from the Antarctic Ice Sheet. Many studies have focused on active basal melting at ice shelves in the Amundsen-Bellingshausen Seas and the Totten Ice shelf, East Antarctica. In these regions, the intrusion of Circumpolar Deep Water (CDW) onto the continental shelf is a key component for the localized intensive basal melting. Both regions have a common oceanographic feature: southward deflection of the Antarctic Circumpolar Current on the eastern flank of ocean gyres brings CDW onto the continental shelves. The physical setting of Shirase Glacier Tongue (SGT) in Lützow-Holm Bay corresponds to a similar configuration for the Weddell Gyre in the Atlantic sector. Here, we conduct a 2–3 km resolution simulation of an ocean-sea ice-ice shelf model using a newly-compiled bottom topography dataset in the bay. The model can reproduce the observed CDW intrusion along the deep trough. The modeled SGT basal melting reaches a peak in summer and minimum in autumn and winter, consistent with the wind-driven seasonality of the CDW thickness in the bay. The model results suggest the existence of eastward-flowing undercurrent on the upper continental slope in summer, and the undercurrent contributes to the seasonal-to-interannual variability of the warm water intrusion into the bay. Furthermore, numerical experiments with and without fast-ice cover in the bay demonstrate that fast ice plays a role as an effective thermal insulator and reduces local sea-ice formation, resulting in much warmer water intrusion into the SGT cavity.

Item Type: Article
Authors/Creators:Kusahara, K and Hirano, D and Fujii, M and Fraser, AD and Tamura, T
Keywords: Antarctic oceanography, water mass modification
Journal or Publication Title: Cryosphere
Publisher: Copernicus GmbH
ISSN: 1994-0416
DOI / ID Number: 10.5194/tc-2020-240
Copyright Information:

Copyright the Author(s) 2021. This work is distributed underthe Creative Commons Attribution 4.0 License

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