Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution
Water mass transformation (WMT) around the Antarctic margin controls Antarctica Bottom Water formation and the abyssal limb of the global meridional overturning circulation, besides mediating ocean-ice shelf exchange, ice sheet stability and its contribution to sea level rise. However, the mechanism...
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2023
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Online Access: | http://dx.doi.org/10.3389/fmars.2023.1027704 https://www.frontiersin.org/articles/10.3389/fmars.2023.1027704/full |
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crfrontiers:10.3389/fmars.2023.1027704 2024-02-11T09:57:49+01:00 Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution Boeira Dias, Fabio Rintoul, Stephen R. Richter, Ole Galton-Fenzi, Benjamin Keith Zika, Jan D. Pellichero, Violaine Uotila, Petteri Academy of Finland Horizon 2020 Framework Programme 2023 http://dx.doi.org/10.3389/fmars.2023.1027704 https://www.frontiersin.org/articles/10.3389/fmars.2023.1027704/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Marine Science volume 10 ISSN 2296-7745 Ocean Engineering Water Science and Technology Aquatic Science Global and Planetary Change Oceanography journal-article 2023 crfrontiers https://doi.org/10.3389/fmars.2023.1027704 2024-01-26T09:56:00Z Water mass transformation (WMT) around the Antarctic margin controls Antarctica Bottom Water formation and the abyssal limb of the global meridional overturning circulation, besides mediating ocean-ice shelf exchange, ice sheet stability and its contribution to sea level rise. However, the mechanisms controlling the rate of WMT in the Antarctic shelf are poorly understood due to the lack of observations and the inability of climate models to simulate those mechanisms, in particular beneath the floating ice shelves. We used a circum-Antarctic ocean-ice shelf model to assess the contribution of surface fluxes, mixing, and ocean-ice shelf interaction to the WMT on the continental shelf. The salt budget dominates the WMT rates, with only a secondary contribution from the heat budget. Basal melt of ice shelves drives buoyancy gain at lighter density classes (27.2<σ θ < 27.6 kg m -3 ), while salt input associated with sea-ice growth in coastal polynyas drives buoyancy loss at heavier densities (σ θ > 27.6). We found a large sensitivity of the WMT rates to model horizontal resolution, tides and topography within the Filchner-Ronne, East and West Antarctica ice shelf cavities. In the Filchner-Ronne Ice Shelf, an anticyclonic circulation in front of the Ronne Depression regulates the rates of basal melting/refreezing and WMT and is substantially affected by tides and model resolution. Model resolution is also found to affect the Antarctic Slope Current in both East and West Antarctica, impacting the on-shelf heat delivery, basal melt and WMT. Moreover, the representation of the ice shelf draft associated with model resolution impacts the freezing temperature and thus basal melt and WMT rates in the East Antarctica. These results highlight the importance of resolving small-scale features of the flow and topography, and to include the effects of tidal forcing, to adequately represent water mass transformations on the shelf that directly influence the abyssal global overturning circulation. Article in Journal/Newspaper Antarc* Antarctic Antarctic Ocean Antarctica East Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Ronne Ice Shelf Sea ice West Antarctica Frontiers (Publisher) Antarctic Antarctic Ocean East Antarctica Ronne Ice Shelf ENVELOPE(-61.000,-61.000,-78.500,-78.500) The Antarctic West Antarctica Frontiers in Marine Science 10 |
institution |
Open Polar |
collection |
Frontiers (Publisher) |
op_collection_id |
crfrontiers |
language |
unknown |
topic |
Ocean Engineering Water Science and Technology Aquatic Science Global and Planetary Change Oceanography |
spellingShingle |
Ocean Engineering Water Science and Technology Aquatic Science Global and Planetary Change Oceanography Boeira Dias, Fabio Rintoul, Stephen R. Richter, Ole Galton-Fenzi, Benjamin Keith Zika, Jan D. Pellichero, Violaine Uotila, Petteri Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution |
topic_facet |
Ocean Engineering Water Science and Technology Aquatic Science Global and Planetary Change Oceanography |
description |
Water mass transformation (WMT) around the Antarctic margin controls Antarctica Bottom Water formation and the abyssal limb of the global meridional overturning circulation, besides mediating ocean-ice shelf exchange, ice sheet stability and its contribution to sea level rise. However, the mechanisms controlling the rate of WMT in the Antarctic shelf are poorly understood due to the lack of observations and the inability of climate models to simulate those mechanisms, in particular beneath the floating ice shelves. We used a circum-Antarctic ocean-ice shelf model to assess the contribution of surface fluxes, mixing, and ocean-ice shelf interaction to the WMT on the continental shelf. The salt budget dominates the WMT rates, with only a secondary contribution from the heat budget. Basal melt of ice shelves drives buoyancy gain at lighter density classes (27.2<σ θ < 27.6 kg m -3 ), while salt input associated with sea-ice growth in coastal polynyas drives buoyancy loss at heavier densities (σ θ > 27.6). We found a large sensitivity of the WMT rates to model horizontal resolution, tides and topography within the Filchner-Ronne, East and West Antarctica ice shelf cavities. In the Filchner-Ronne Ice Shelf, an anticyclonic circulation in front of the Ronne Depression regulates the rates of basal melting/refreezing and WMT and is substantially affected by tides and model resolution. Model resolution is also found to affect the Antarctic Slope Current in both East and West Antarctica, impacting the on-shelf heat delivery, basal melt and WMT. Moreover, the representation of the ice shelf draft associated with model resolution impacts the freezing temperature and thus basal melt and WMT rates in the East Antarctica. These results highlight the importance of resolving small-scale features of the flow and topography, and to include the effects of tidal forcing, to adequately represent water mass transformations on the shelf that directly influence the abyssal global overturning circulation. |
author2 |
Academy of Finland Horizon 2020 Framework Programme |
format |
Article in Journal/Newspaper |
author |
Boeira Dias, Fabio Rintoul, Stephen R. Richter, Ole Galton-Fenzi, Benjamin Keith Zika, Jan D. Pellichero, Violaine Uotila, Petteri |
author_facet |
Boeira Dias, Fabio Rintoul, Stephen R. Richter, Ole Galton-Fenzi, Benjamin Keith Zika, Jan D. Pellichero, Violaine Uotila, Petteri |
author_sort |
Boeira Dias, Fabio |
title |
Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution |
title_short |
Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution |
title_full |
Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution |
title_fullStr |
Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution |
title_full_unstemmed |
Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution |
title_sort |
sensitivity of simulated water mass transformation on the antarctic shelf to tides, topography and model resolution |
publisher |
Frontiers Media SA |
publishDate |
2023 |
url |
http://dx.doi.org/10.3389/fmars.2023.1027704 https://www.frontiersin.org/articles/10.3389/fmars.2023.1027704/full |
long_lat |
ENVELOPE(-61.000,-61.000,-78.500,-78.500) |
geographic |
Antarctic Antarctic Ocean East Antarctica Ronne Ice Shelf The Antarctic West Antarctica |
geographic_facet |
Antarctic Antarctic Ocean East Antarctica Ronne Ice Shelf The Antarctic West Antarctica |
genre |
Antarc* Antarctic Antarctic Ocean Antarctica East Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Ronne Ice Shelf Sea ice West Antarctica |
genre_facet |
Antarc* Antarctic Antarctic Ocean Antarctica East Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Ronne Ice Shelf Sea ice West Antarctica |
op_source |
Frontiers in Marine Science volume 10 ISSN 2296-7745 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3389/fmars.2023.1027704 |
container_title |
Frontiers in Marine Science |
container_volume |
10 |
_version_ |
1790593361381425152 |