The role of double-diffusive convection in basal melting of Antarctic ice shelves

The Antarctic Ice Sheet loses about half its mass through ocean-driven melting of its fringing ice shelves. However, the ocean processes governing ice shelf melting are not well understood, contributing to uncertainty in projections of Antarctica’s contribution to global sea level. We use high-resol...

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Published in:Proceedings of the National Academy of Sciences
Main Authors: Rosevear, Madelaine Gamble, Gayen, Bishakhdatta, Galton-Fenzi, Benjamin Keith
Format: Text
Language:English
Published: National Academy of Sciences 2021
Subjects:
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8017962/
http://www.ncbi.nlm.nih.gov/pubmed/33547235
https://doi.org/10.1073/pnas.2007541118
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spelling ftpubmed:oai:pubmedcentral.nih.gov:8017962 2023-05-15T13:32:13+02:00 The role of double-diffusive convection in basal melting of Antarctic ice shelves Rosevear, Madelaine Gamble Gayen, Bishakhdatta Galton-Fenzi, Benjamin Keith 2021-02-09 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8017962/ http://www.ncbi.nlm.nih.gov/pubmed/33547235 https://doi.org/10.1073/pnas.2007541118 en eng National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8017962/ http://www.ncbi.nlm.nih.gov/pubmed/33547235 http://dx.doi.org/10.1073/pnas.2007541118 https://www.pnas.org/site/aboutpnas/licenses.xhtmlPublished under the PNAS license (https://www.pnas.org/site/aboutpnas/licenses.xhtml) . Proc Natl Acad Sci U S A Physical Sciences Text 2021 ftpubmed https://doi.org/10.1073/pnas.2007541118 2021-08-08T00:33:29Z The Antarctic Ice Sheet loses about half its mass through ocean-driven melting of its fringing ice shelves. However, the ocean processes governing ice shelf melting are not well understood, contributing to uncertainty in projections of Antarctica’s contribution to global sea level. We use high-resolution large-eddy simulation to examine ocean-driven melt, in a geophysical-scale model of the turbulent ice shelf–ocean boundary layer, focusing on the ocean conditions observed beneath the Ross Ice Shelf. We quantify the role of double-diffusive convection in determining ice shelf melt rates and oceanic mixed layer properties in relatively warm and low-velocity cavity environments. We demonstrate that double-diffusive convection is the first-order process controlling the melt rate and mixed layer evolution at these flow conditions, even more important than vertical shear due to a mean flow, and is responsible for the step-like temperature and salinity structure, or thermohaline staircase, observed beneath the ice. A robust feature of the multiday simulations is a growing saline diffusive sublayer that drives a time-dependent melt rate. This melt rate is lower than current ice–ocean parameterizations, which consider only shear-controlled turbulent melting, would predict. Our main finding is that double-diffusive convection is an important process beneath ice shelves, yet is currently neglected in ocean–climate models. Text Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf PubMed Central (PMC) Antarctic Ross Ice Shelf The Antarctic Proceedings of the National Academy of Sciences 118 6 e2007541118
institution Open Polar
collection PubMed Central (PMC)
op_collection_id ftpubmed
language English
topic Physical Sciences
spellingShingle Physical Sciences
Rosevear, Madelaine Gamble
Gayen, Bishakhdatta
Galton-Fenzi, Benjamin Keith
The role of double-diffusive convection in basal melting of Antarctic ice shelves
topic_facet Physical Sciences
description The Antarctic Ice Sheet loses about half its mass through ocean-driven melting of its fringing ice shelves. However, the ocean processes governing ice shelf melting are not well understood, contributing to uncertainty in projections of Antarctica’s contribution to global sea level. We use high-resolution large-eddy simulation to examine ocean-driven melt, in a geophysical-scale model of the turbulent ice shelf–ocean boundary layer, focusing on the ocean conditions observed beneath the Ross Ice Shelf. We quantify the role of double-diffusive convection in determining ice shelf melt rates and oceanic mixed layer properties in relatively warm and low-velocity cavity environments. We demonstrate that double-diffusive convection is the first-order process controlling the melt rate and mixed layer evolution at these flow conditions, even more important than vertical shear due to a mean flow, and is responsible for the step-like temperature and salinity structure, or thermohaline staircase, observed beneath the ice. A robust feature of the multiday simulations is a growing saline diffusive sublayer that drives a time-dependent melt rate. This melt rate is lower than current ice–ocean parameterizations, which consider only shear-controlled turbulent melting, would predict. Our main finding is that double-diffusive convection is an important process beneath ice shelves, yet is currently neglected in ocean–climate models.
format Text
author Rosevear, Madelaine Gamble
Gayen, Bishakhdatta
Galton-Fenzi, Benjamin Keith
author_facet Rosevear, Madelaine Gamble
Gayen, Bishakhdatta
Galton-Fenzi, Benjamin Keith
author_sort Rosevear, Madelaine Gamble
title The role of double-diffusive convection in basal melting of Antarctic ice shelves
title_short The role of double-diffusive convection in basal melting of Antarctic ice shelves
title_full The role of double-diffusive convection in basal melting of Antarctic ice shelves
title_fullStr The role of double-diffusive convection in basal melting of Antarctic ice shelves
title_full_unstemmed The role of double-diffusive convection in basal melting of Antarctic ice shelves
title_sort role of double-diffusive convection in basal melting of antarctic ice shelves
publisher National Academy of Sciences
publishDate 2021
url http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8017962/
http://www.ncbi.nlm.nih.gov/pubmed/33547235
https://doi.org/10.1073/pnas.2007541118
geographic Antarctic
Ross Ice Shelf
The Antarctic
geographic_facet Antarctic
Ross Ice Shelf
The Antarctic
genre Antarc*
Antarctic
Ice Sheet
Ice Shelf
Ice Shelves
Ross Ice Shelf
genre_facet Antarc*
Antarctic
Ice Sheet
Ice Shelf
Ice Shelves
Ross Ice Shelf
op_source Proc Natl Acad Sci U S A
op_relation http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8017962/
http://www.ncbi.nlm.nih.gov/pubmed/33547235
http://dx.doi.org/10.1073/pnas.2007541118
op_rights https://www.pnas.org/site/aboutpnas/licenses.xhtmlPublished under the PNAS license (https://www.pnas.org/site/aboutpnas/licenses.xhtml) .
op_doi https://doi.org/10.1073/pnas.2007541118
container_title Proceedings of the National Academy of Sciences
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container_issue 6
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