Southern Ocean polynyas in CMIP6 models
Polynyas facilitate air–sea fluxes, impacting climate-relevant properties such as sea ice formation and deep water production. Despite their importance, polynyas have been poorly represented in past generations of climate models. Here we present a method to track the presence, frequency and spatial...
Published in: | The Cryosphere |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2021
|
Subjects: | |
Online Access: | https://doi.org/10.5194/tc-15-4281-2021 https://doaj.org/article/e13dc47752ca4730be1d8af433ca3c7d |
id |
ftdoajarticles:oai:doaj.org/article:e13dc47752ca4730be1d8af433ca3c7d |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:e13dc47752ca4730be1d8af433ca3c7d 2023-05-15T13:55:11+02:00 Southern Ocean polynyas in CMIP6 models M. Mohrmann C. Heuzé S. Swart 2021-09-01T00:00:00Z https://doi.org/10.5194/tc-15-4281-2021 https://doaj.org/article/e13dc47752ca4730be1d8af433ca3c7d EN eng Copernicus Publications https://tc.copernicus.org/articles/15/4281/2021/tc-15-4281-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-4281-2021 1994-0416 1994-0424 https://doaj.org/article/e13dc47752ca4730be1d8af433ca3c7d The Cryosphere, Vol 15, Pp 4281-4313 (2021) Environmental sciences GE1-350 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.5194/tc-15-4281-2021 2022-12-31T16:36:40Z Polynyas facilitate air–sea fluxes, impacting climate-relevant properties such as sea ice formation and deep water production. Despite their importance, polynyas have been poorly represented in past generations of climate models. Here we present a method to track the presence, frequency and spatial distribution of polynyas in the Southern Ocean in 27 models participating in the Climate Model Intercomparison Project Phase 6 (CMIP6) and two satellite-based sea ice products. Only half of the 27 models form open-water polynyas (OWPs), and most underestimate their area. As in satellite observations, three models show episodes of high OWP activity separated by decades of no OWP, while other models unrealistically create OWPs nearly every year. In contrast, the coastal polynya area is overestimated in most models, with the least accurate representations occurring in the models with the coarsest horizontal resolution. We show that the presence or absence of OWPs is linked to changes in the regional hydrography, specifically the linkages between polynya activity with deep water convection and/or the shoaling of the upper water column thermocline. Models with an accurate Antarctic Circumpolar Current transport and wind stress curl have too frequent OWPs. Biases in polynya representation continue to exist in climate models, which has an impact on the regional ocean circulation and ventilation that should be addressed. However, emerging iceberg discharge schemes, more adequate vertical grid type or overflow parameterisation are anticipated to improve polynya representations and associated climate prediction in the future. Article in Journal/Newspaper Antarc* Antarctic Iceberg* Sea ice Southern Ocean The Cryosphere Directory of Open Access Journals: DOAJ Articles Antarctic Southern Ocean Curl ENVELOPE(-63.071,-63.071,-70.797,-70.797) The Cryosphere 15 9 4281 4313 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 M. Mohrmann C. Heuzé S. Swart Southern Ocean polynyas in CMIP6 models |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Polynyas facilitate air–sea fluxes, impacting climate-relevant properties such as sea ice formation and deep water production. Despite their importance, polynyas have been poorly represented in past generations of climate models. Here we present a method to track the presence, frequency and spatial distribution of polynyas in the Southern Ocean in 27 models participating in the Climate Model Intercomparison Project Phase 6 (CMIP6) and two satellite-based sea ice products. Only half of the 27 models form open-water polynyas (OWPs), and most underestimate their area. As in satellite observations, three models show episodes of high OWP activity separated by decades of no OWP, while other models unrealistically create OWPs nearly every year. In contrast, the coastal polynya area is overestimated in most models, with the least accurate representations occurring in the models with the coarsest horizontal resolution. We show that the presence or absence of OWPs is linked to changes in the regional hydrography, specifically the linkages between polynya activity with deep water convection and/or the shoaling of the upper water column thermocline. Models with an accurate Antarctic Circumpolar Current transport and wind stress curl have too frequent OWPs. Biases in polynya representation continue to exist in climate models, which has an impact on the regional ocean circulation and ventilation that should be addressed. However, emerging iceberg discharge schemes, more adequate vertical grid type or overflow parameterisation are anticipated to improve polynya representations and associated climate prediction in the future. |
format |
Article in Journal/Newspaper |
author |
M. Mohrmann C. Heuzé S. Swart |
author_facet |
M. Mohrmann C. Heuzé S. Swart |
author_sort |
M. Mohrmann |
title |
Southern Ocean polynyas in CMIP6 models |
title_short |
Southern Ocean polynyas in CMIP6 models |
title_full |
Southern Ocean polynyas in CMIP6 models |
title_fullStr |
Southern Ocean polynyas in CMIP6 models |
title_full_unstemmed |
Southern Ocean polynyas in CMIP6 models |
title_sort |
southern ocean polynyas in cmip6 models |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-4281-2021 https://doaj.org/article/e13dc47752ca4730be1d8af433ca3c7d |
long_lat |
ENVELOPE(-63.071,-63.071,-70.797,-70.797) |
geographic |
Antarctic Southern Ocean Curl |
geographic_facet |
Antarctic Southern Ocean Curl |
genre |
Antarc* Antarctic Iceberg* Sea ice Southern Ocean The Cryosphere |
genre_facet |
Antarc* Antarctic Iceberg* Sea ice Southern Ocean The Cryosphere |
op_source |
The Cryosphere, Vol 15, Pp 4281-4313 (2021) |
op_relation |
https://tc.copernicus.org/articles/15/4281/2021/tc-15-4281-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-4281-2021 1994-0416 1994-0424 https://doaj.org/article/e13dc47752ca4730be1d8af433ca3c7d |
op_doi |
https://doi.org/10.5194/tc-15-4281-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
9 |
container_start_page |
4281 |
op_container_end_page |
4313 |
_version_ |
1766261480300216320 |