Effects of the atmospheric forcing resolution on simulated sea ice and polynyas off Adélie Land, East Antarctica

Pierre Vincent Huot; Christoph Kittel; Thierry Fichefet; Nicolas C. Jourdain; Jean Sterlin; Xavier Fettweis

doi:10.1016/j.ocemod.2021.101901

Effects of the atmospheric forcing resolution on simulated sea ice and polynyas off Adélie Land, East Antarctica

Pierre Vincent Huot, Christoph Kittel, Thierry Fichefet, Nicolas C. Jourdain, Jean Sterlin, Xavier Fettweis

Research output: Contribution to journal › Article › peer-review

8 Citations (Scopus)

Abstract

Coastal polynyas of the Southern Ocean play a central role in the ventilation of the deep ocean and affect the stability of ice shelves. It appears crucial to incorporate them into climate models, but it is unclear how to adequately simulate them. In particular, there is no consensus on the atmospheric forcing resolution needed to appropriately model the sea ice in coastal Antarctica. A high resolution might be required to represent the local winds such as katabatic winds which are key drivers of coastal polynyas. To fill in this gap, we have tested the sensitivity of sea ice and air-sea-ice interactions to the resolution of the atmospheric forcing in a high-resolution ocean–sea ice model. A set of regional atmospheric simulations at horizontal resolutions of 20, 10, and 5 km are performed with an atmospheric regional model and used to force three ocean–sea ice simulations in the Adélie Land sector, East Antarctica. Due to the better representation of topography with a refined grid, the offshore component of coastal winds becomes stronger at increased resolution. The wind intensification is particularly strong down valleys channelizing the katabatic flow, with increase in wind speed ranging between 1 and 3 m/s. Under a higher resolution forcing, polynyas open more frequently and are wider. This fosters the growth rate of sea ice in polynyas, while landfast ice and pack ice are weakly affected. In polynyas, the production of sea ice is increased by up to 30% at 5 km resolution compared to 20 km resolution. Polynyas downstream of the katabatic wind pathway are more affected than the ones driven by easterly winds, highlighting the importance of the local wind conditions. Brine rejection associated with these higher sea ice production rates affects the salinity budget of the ocean and enhances both the volume and density of the dense Shelf Water produced off Adélie Land. These results underpin the need to better account for local coastal winds and polynyas in ocean and climate models.

Original language	English
Article number	101901
Pages (from-to)	1-17
Number of pages	17
Journal	Ocean Modelling
Volume	168
DOIs	https://doi.org/10.1016/j.ocemod.2021.101901
Publication status	Published - Dec 2021
Externally published	Yes

Bibliographical note

Funding Information:
The authors are thankful to the two anonymous reviewers who helped to improve the manuscript. This research was conducted within the F.R.S.-FNRS PDR T.0002.16 “Air-Ice-Ocean Interactions in Antarctica” and the PARAMOUR project, funded by the Research Foundation-Flanders ( Research Foundation – Flanders (FWO) ) and F.R.S.-FNRS under the Excellence of Science (EOS) programme (grant EOS O0100718F ). Computational resources have been provided by the supercomputing facilities of the Université catholique de Louvain (CISM/UCL) and the Consortium des Équipements de Calcul Intensif en Fédération Wallonie Bruxelles (CÉCI) funded by the Fond de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under convention 2.5020.11. The present research benefited from computational resources made available on the Tier-1 supercomputer of the Fédération Wallonie-Bruxelles, infrastructure funded by the Walloon Region under the grant agreement n° 1117545 .

Publisher Copyright:
© 2021

Keywords

Dense Shelf Water
East Antarctica
High resolution
Katabatic wind
Landfast ice
Polynya

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title = "Effects of the atmospheric forcing resolution on simulated sea ice and polynyas off Ad{\'e}lie Land, East Antarctica",

abstract = "Coastal polynyas of the Southern Ocean play a central role in the ventilation of the deep ocean and affect the stability of ice shelves. It appears crucial to incorporate them into climate models, but it is unclear how to adequately simulate them. In particular, there is no consensus on the atmospheric forcing resolution needed to appropriately model the sea ice in coastal Antarctica. A high resolution might be required to represent the local winds such as katabatic winds which are key drivers of coastal polynyas. To fill in this gap, we have tested the sensitivity of sea ice and air-sea-ice interactions to the resolution of the atmospheric forcing in a high-resolution ocean–sea ice model. A set of regional atmospheric simulations at horizontal resolutions of 20, 10, and 5 km are performed with an atmospheric regional model and used to force three ocean–sea ice simulations in the Ad{\'e}lie Land sector, East Antarctica. Due to the better representation of topography with a refined grid, the offshore component of coastal winds becomes stronger at increased resolution. The wind intensification is particularly strong down valleys channelizing the katabatic flow, with increase in wind speed ranging between 1 and 3 m/s. Under a higher resolution forcing, polynyas open more frequently and are wider. This fosters the growth rate of sea ice in polynyas, while landfast ice and pack ice are weakly affected. In polynyas, the production of sea ice is increased by up to 30% at 5 km resolution compared to 20 km resolution. Polynyas downstream of the katabatic wind pathway are more affected than the ones driven by easterly winds, highlighting the importance of the local wind conditions. Brine rejection associated with these higher sea ice production rates affects the salinity budget of the ocean and enhances both the volume and density of the dense Shelf Water produced off Ad{\'e}lie Land. These results underpin the need to better account for local coastal winds and polynyas in ocean and climate models.",

keywords = "Dense Shelf Water, East Antarctica, High resolution, Katabatic wind, Landfast ice, Polynya",

author = "Huot, {Pierre Vincent} and Christoph Kittel and Thierry Fichefet and Jourdain, {Nicolas C.} and Jean Sterlin and Xavier Fettweis",

note = "Funding Information: The authors are thankful to the two anonymous reviewers who helped to improve the manuscript. This research was conducted within the F.R.S.-FNRS PDR T.0002.16 “Air-Ice-Ocean Interactions in Antarctica” and the PARAMOUR project, funded by the Research Foundation-Flanders ( Research Foundation – Flanders (FWO) ) and F.R.S.-FNRS under the Excellence of Science (EOS) programme (grant EOS O0100718F ). Computational resources have been provided by the supercomputing facilities of the Universit{\'e} catholique de Louvain (CISM/UCL) and the Consortium des {\'E}quipements de Calcul Intensif en F{\'e}d{\'e}ration Wallonie Bruxelles (C{\'E}CI) funded by the Fond de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under convention 2.5020.11. The present research benefited from computational resources made available on the Tier-1 supercomputer of the F{\'e}d{\'e}ration Wallonie-Bruxelles, infrastructure funded by the Walloon Region under the grant agreement n° 1117545 . Publisher Copyright: {\textcopyright} 2021",

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doi = "10.1016/j.ocemod.2021.101901",

language = "English",

volume = "168",

pages = "1--17",

journal = "Ocean Modelling",

issn = "1463-5003",

publisher = "Elsevier BV",

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T1 - Effects of the atmospheric forcing resolution on simulated sea ice and polynyas off Adélie Land, East Antarctica

AU - Huot, Pierre Vincent

AU - Kittel, Christoph

AU - Fichefet, Thierry

AU - Jourdain, Nicolas C.

AU - Sterlin, Jean

AU - Fettweis, Xavier

N1 - Funding Information: The authors are thankful to the two anonymous reviewers who helped to improve the manuscript. This research was conducted within the F.R.S.-FNRS PDR T.0002.16 “Air-Ice-Ocean Interactions in Antarctica” and the PARAMOUR project, funded by the Research Foundation-Flanders ( Research Foundation – Flanders (FWO) ) and F.R.S.-FNRS under the Excellence of Science (EOS) programme (grant EOS O0100718F ). Computational resources have been provided by the supercomputing facilities of the Université catholique de Louvain (CISM/UCL) and the Consortium des Équipements de Calcul Intensif en Fédération Wallonie Bruxelles (CÉCI) funded by the Fond de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under convention 2.5020.11. The present research benefited from computational resources made available on the Tier-1 supercomputer of the Fédération Wallonie-Bruxelles, infrastructure funded by the Walloon Region under the grant agreement n° 1117545 . Publisher Copyright: © 2021

PY - 2021/12

Y1 - 2021/12

N2 - Coastal polynyas of the Southern Ocean play a central role in the ventilation of the deep ocean and affect the stability of ice shelves. It appears crucial to incorporate them into climate models, but it is unclear how to adequately simulate them. In particular, there is no consensus on the atmospheric forcing resolution needed to appropriately model the sea ice in coastal Antarctica. A high resolution might be required to represent the local winds such as katabatic winds which are key drivers of coastal polynyas. To fill in this gap, we have tested the sensitivity of sea ice and air-sea-ice interactions to the resolution of the atmospheric forcing in a high-resolution ocean–sea ice model. A set of regional atmospheric simulations at horizontal resolutions of 20, 10, and 5 km are performed with an atmospheric regional model and used to force three ocean–sea ice simulations in the Adélie Land sector, East Antarctica. Due to the better representation of topography with a refined grid, the offshore component of coastal winds becomes stronger at increased resolution. The wind intensification is particularly strong down valleys channelizing the katabatic flow, with increase in wind speed ranging between 1 and 3 m/s. Under a higher resolution forcing, polynyas open more frequently and are wider. This fosters the growth rate of sea ice in polynyas, while landfast ice and pack ice are weakly affected. In polynyas, the production of sea ice is increased by up to 30% at 5 km resolution compared to 20 km resolution. Polynyas downstream of the katabatic wind pathway are more affected than the ones driven by easterly winds, highlighting the importance of the local wind conditions. Brine rejection associated with these higher sea ice production rates affects the salinity budget of the ocean and enhances both the volume and density of the dense Shelf Water produced off Adélie Land. These results underpin the need to better account for local coastal winds and polynyas in ocean and climate models.

AB - Coastal polynyas of the Southern Ocean play a central role in the ventilation of the deep ocean and affect the stability of ice shelves. It appears crucial to incorporate them into climate models, but it is unclear how to adequately simulate them. In particular, there is no consensus on the atmospheric forcing resolution needed to appropriately model the sea ice in coastal Antarctica. A high resolution might be required to represent the local winds such as katabatic winds which are key drivers of coastal polynyas. To fill in this gap, we have tested the sensitivity of sea ice and air-sea-ice interactions to the resolution of the atmospheric forcing in a high-resolution ocean–sea ice model. A set of regional atmospheric simulations at horizontal resolutions of 20, 10, and 5 km are performed with an atmospheric regional model and used to force three ocean–sea ice simulations in the Adélie Land sector, East Antarctica. Due to the better representation of topography with a refined grid, the offshore component of coastal winds becomes stronger at increased resolution. The wind intensification is particularly strong down valleys channelizing the katabatic flow, with increase in wind speed ranging between 1 and 3 m/s. Under a higher resolution forcing, polynyas open more frequently and are wider. This fosters the growth rate of sea ice in polynyas, while landfast ice and pack ice are weakly affected. In polynyas, the production of sea ice is increased by up to 30% at 5 km resolution compared to 20 km resolution. Polynyas downstream of the katabatic wind pathway are more affected than the ones driven by easterly winds, highlighting the importance of the local wind conditions. Brine rejection associated with these higher sea ice production rates affects the salinity budget of the ocean and enhances both the volume and density of the dense Shelf Water produced off Adélie Land. These results underpin the need to better account for local coastal winds and polynyas in ocean and climate models.

KW - Dense Shelf Water

KW - East Antarctica

KW - High resolution

KW - Katabatic wind

KW - Landfast ice

KW - Polynya

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U2 - 10.1016/j.ocemod.2021.101901

DO - 10.1016/j.ocemod.2021.101901

M3 - Article

AN - SCOPUS:85118889261

SN - 1463-5003

VL - 168

SP - 1

EP - 17

JO - Ocean Modelling

JF - Ocean Modelling

M1 - 101901

ER -

Effects of the atmospheric forcing resolution on simulated sea ice and polynyas off Adélie Land, East Antarctica

Abstract

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Keywords

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