File(s) under permanent embargo
Freshening by glacial meltwater enhances melting of ice shelves and reduces formation of Antarctic Bottom Water
journal contribution
posted on 2023-05-19, 17:32 authored by Silvano, A, Stephen Rintoul, Beatriz Pena-MolinoBeatriz Pena-Molino, William HobbsWilliam Hobbs, van Wijk, E, Aoki, S, Tamura, T, Guy WilliamsStrong heat loss and brine release during sea ice formation in coastal polynyas act to cool and salinify waters on the Antarctic continental shelf. Polynya activity thus both limits the ocean heat flux to the Antarctic Ice Sheet and promotes formation of Dense Shelf Water (DSW), the precursor to Antarctic Bottom Water. However, despite the presence of strong polynyas, DSW is not formed on the Sabrina Coast in East Antarctica and in the Amundsen Sea in West Antarctica. Using a simple ocean model driven by observed forcing, we show that freshwater input from basal melt of ice shelves partially offsets the salt flux by sea ice formation in polynyas found in both regions, preventing full-depth convection and formation of DSW. In the absence of deep convection, warm water that reaches the continental shelf in the bottom layer does not lose much heat to the atmosphere and is thus available to drive the rapid basal melt observed at the Totten Ice Shelf on the Sabrina Coast and at the Dotson and Getz ice shelves in the Amundsen Sea. Our results suggest that increased glacial meltwater input in a warming climate will both reduce Antarctic Bottom Water formation and trigger increased mass loss from the Antarctic Ice Sheet, with consequences for the global overturning circulation and sea level rise.
History
Publication title
Science AdvancesVolume
4Issue
4Article number
eaap9467Number
eaap9467Pagination
1-12ISSN
2375-2548Department/School
Institute for Marine and Antarctic StudiesPublisher
American Association for the Advancement of SciencePlace of publication
United StatesRights statement
Copyright 2018 The Authors. Licensed under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) https://creativecommons.org/licenses/by-nc/4.0/Repository Status
- Restricted