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...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-04-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2023.1027704/full |
| _version_ | 1827968288445956096 |
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| author | Fabio Boeira Dias Fabio Boeira Dias Fabio Boeira Dias Stephen R. Rintoul Stephen R. Rintoul Ole Richter Benjamin Keith Galton-Fenzi Benjamin Keith Galton-Fenzi Benjamin Keith Galton-Fenzi Jan D. Zika Jan D. Zika Violaine Pellichero Violaine Pellichero Petteri Uotila |
| author_facet | Fabio Boeira Dias Fabio Boeira Dias Fabio Boeira Dias Stephen R. Rintoul Stephen R. Rintoul Ole Richter Benjamin Keith Galton-Fenzi Benjamin Keith Galton-Fenzi Benjamin Keith Galton-Fenzi Jan D. Zika Jan D. Zika Violaine Pellichero Violaine Pellichero Petteri Uotila |
| author_sort | Fabio Boeira Dias |
| collection | DOAJ |
| 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<σθ< 27.6 kg m-3), while salt input associated with sea-ice growth in coastal polynyas drives buoyancy loss at heavier densities (σθ> 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. |
| first_indexed | 2024-04-09T18:18:39Z |
| format | Article |
| id | doaj.art-32302671aecf40a19b3a3399e746ee08 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-09T18:18:39Z |
| publishDate | 2023-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-32302671aecf40a19b3a3399e746ee082023-04-12T13:23:04ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452023-04-011010.3389/fmars.2023.10277041027704Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolutionFabio Boeira Dias0Fabio Boeira Dias1Fabio Boeira Dias2Stephen R. Rintoul3Stephen R. Rintoul4Ole Richter5Benjamin Keith Galton-Fenzi6Benjamin Keith Galton-Fenzi7Benjamin Keith Galton-Fenzi8Jan D. Zika9Jan D. Zika10Violaine Pellichero11Violaine Pellichero12Petteri Uotila13Institute of Atmospheric and Earth System Research, University of Helsinki, Helsinki, FinlandClimate Change Research Centre, University of New South Wales, Sydney, NSW, AustraliaAustralian Centre for Excellence in Antarctic Science (ACEAS), University of New South Wales, Sydney, NSW, AustraliaCSIRO Environment, nipaluna/Hobart, TAS, AustraliaAustralian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, nipaluna/Hobart, TAS, AustraliaPhysical Oceanography of Polar Seas, Alfred Wegener Institute, Bremerhaven, GermanyAustralian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, nipaluna/Hobart, TAS, AustraliaAustralian Antarctic Division, Kingston, TAS, AustraliaAustralian Centre for Excellence in Antarctic Science, University of Tasmania, nipaluna/Hobart, TAS, AustraliaAustralian Centre for Excellence in Antarctic Science (ACEAS), University of New South Wales, Sydney, NSW, AustraliaUNSW Data Science Hub and School of Mathematics and Statistics, University of New South Wales, Sydney, NSW, AustraliaCSIRO Environment, nipaluna/Hobart, TAS, Australia0Institute for Marine Antarctic Studies, University of Tasmania, nipaluna/Hobart, TAS, AustraliaInstitute of Atmospheric and Earth System Research, University of Helsinki, Helsinki, FinlandWater 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<σθ< 27.6 kg m-3), while salt input associated with sea-ice growth in coastal polynyas drives buoyancy loss at heavier densities (σθ> 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.https://www.frontiersin.org/articles/10.3389/fmars.2023.1027704/fullSouthern OceanAntarctic shelfwater mass transformationhigh salinity shelf water (HSSW)ice shelf water (ISW)coastal polynyas |
| spellingShingle | Fabio Boeira Dias Fabio Boeira Dias Fabio Boeira Dias Stephen R. Rintoul Stephen R. Rintoul Ole Richter Benjamin Keith Galton-Fenzi Benjamin Keith Galton-Fenzi Benjamin Keith Galton-Fenzi Jan D. Zika Jan D. Zika Violaine Pellichero Violaine Pellichero Petteri Uotila Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution Frontiers in Marine Science Southern Ocean Antarctic shelf water mass transformation high salinity shelf water (HSSW) ice shelf water (ISW) coastal polynyas |
| title | 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_short | 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 |
| topic | Southern Ocean Antarctic shelf water mass transformation high salinity shelf water (HSSW) ice shelf water (ISW) coastal polynyas |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2023.1027704/full |
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