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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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 |
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English |
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Physical Sciences |
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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 |
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Proceedings of the National Academy of Sciences |
container_volume |
118 |
container_issue |
6 |
container_start_page |
e2007541118 |
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1766025136700391424 |