Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP
One of the major globally relevant systematic biases in previous generations of climate models has been an equatorward bias in the latitude of the Southern Hemisphere (SH) mid-latitude tropospheric eddy driven westerly jet. The far-reaching implications of this for Southern Ocean heat and carbon upt...
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ftconicet:oai:ri.conicet.gov.ar:11336/144092 2023-10-09T21:44:29+02:00 Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP Bracegirdle, T.J. Holmes, C.R. Hosking, J.S. Marshall, G.J. Osman, Marisol Patterson, M. Rackow, T. application/pdf http://hdl.handle.net/11336/144092 eng eng Wiley Blackwell Publishing, Inc info:eu-repo/semantics/altIdentifier/url/https://onlinelibrary.wiley.com/doi/abs/10.1029/2019EA001065 info:eu-repo/semantics/altIdentifier/doi/10.1029/2019EA001065 http://hdl.handle.net/11336/144092 Bracegirdle, T.J.; Holmes, C.R.; Hosking, J.S.; Marshall, G.J.; Osman, Marisol; et al.; Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP; Wiley Blackwell Publishing, Inc; Earth and Space Science; 7; 6; 5-2020; 1-25 2333-5084 CONICET Digital CONICET info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/2.5/ar/ AMUNDSEN SEA LOW ANTARCTIC CMIP5 CMIP6 SOUTHERN OCEAN WESTERLY JET https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion ftconicet https://doi.org/10.1029/2019EA001065 2023-09-24T19:27:31Z One of the major globally relevant systematic biases in previous generations of climate models has been an equatorward bias in the latitude of the Southern Hemisphere (SH) mid-latitude tropospheric eddy driven westerly jet. The far-reaching implications of this for Southern Ocean heat and carbon uptake and Antarctic land and sea ice are key reasons why addressing this bias is a high priority. It is therefore of primary importance to evaluate the representation of the SH westerly jet in the latest generation of global climate and earth system models that comprise the Coupled Model Intercomparison Project Phase 6 (CMIP6). In this paper we assess the representation of major indices of SH extratropical atmospheric circulation in CMIP6 by comparison against both observations and the previous generation of CMIP5 models. Indices assessed are the latitude and speed of the westerly jet, variability of the Southern Annular Mode (SAM), and representation of the Amundsen Sea Low (ASL). These are calculated from the historical forcing simulations of both CMIP5 and CMIP6 for time periods matching available observational and reanalysis data sets. From the 39 CMIP6 models available at the time of writing there is an overall reduction in the equatorward bias of the annual mean westerly jet from 1.9° in CMIP5 to 0.4° in CMIP6 and from a seasonal perspective the reduction is clearest in austral spring and summer. This is accompanied by a halving of the bias of SAM decorrelation timescales compared to CMIP5. However, no such overall improvements are evident for the ASL. Fil: Bracegirdle, T.J. British Antarctic Survey; Reino Unido Fil: Holmes, C.R. British Artarctic Survey; Reino Unido Fil: Hosking, J.S. British Antarctic Survey; Reino Unido Fil: Marshall, G.J. British Antarctic Survey; Reino Unido Fil: Osman, Marisol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. ... Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic British Antarctic Survey Sea ice Southern Ocean CONICET Digital (Consejo Nacional de Investigaciones Científicas y Técnicas) Antarctic Southern Ocean Austral Amundsen Sea Earth and Space Science 7 6 |
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CONICET Digital (Consejo Nacional de Investigaciones Científicas y Técnicas) |
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language |
English |
topic |
AMUNDSEN SEA LOW ANTARCTIC CMIP5 CMIP6 SOUTHERN OCEAN WESTERLY JET https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
spellingShingle |
AMUNDSEN SEA LOW ANTARCTIC CMIP5 CMIP6 SOUTHERN OCEAN WESTERLY JET https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 Bracegirdle, T.J. Holmes, C.R. Hosking, J.S. Marshall, G.J. Osman, Marisol Patterson, M. Rackow, T. Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP |
topic_facet |
AMUNDSEN SEA LOW ANTARCTIC CMIP5 CMIP6 SOUTHERN OCEAN WESTERLY JET https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
description |
One of the major globally relevant systematic biases in previous generations of climate models has been an equatorward bias in the latitude of the Southern Hemisphere (SH) mid-latitude tropospheric eddy driven westerly jet. The far-reaching implications of this for Southern Ocean heat and carbon uptake and Antarctic land and sea ice are key reasons why addressing this bias is a high priority. It is therefore of primary importance to evaluate the representation of the SH westerly jet in the latest generation of global climate and earth system models that comprise the Coupled Model Intercomparison Project Phase 6 (CMIP6). In this paper we assess the representation of major indices of SH extratropical atmospheric circulation in CMIP6 by comparison against both observations and the previous generation of CMIP5 models. Indices assessed are the latitude and speed of the westerly jet, variability of the Southern Annular Mode (SAM), and representation of the Amundsen Sea Low (ASL). These are calculated from the historical forcing simulations of both CMIP5 and CMIP6 for time periods matching available observational and reanalysis data sets. From the 39 CMIP6 models available at the time of writing there is an overall reduction in the equatorward bias of the annual mean westerly jet from 1.9° in CMIP5 to 0.4° in CMIP6 and from a seasonal perspective the reduction is clearest in austral spring and summer. This is accompanied by a halving of the bias of SAM decorrelation timescales compared to CMIP5. However, no such overall improvements are evident for the ASL. Fil: Bracegirdle, T.J. British Antarctic Survey; Reino Unido Fil: Holmes, C.R. British Artarctic Survey; Reino Unido Fil: Hosking, J.S. British Antarctic Survey; Reino Unido Fil: Marshall, G.J. British Antarctic Survey; Reino Unido Fil: Osman, Marisol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. ... |
format |
Article in Journal/Newspaper |
author |
Bracegirdle, T.J. Holmes, C.R. Hosking, J.S. Marshall, G.J. Osman, Marisol Patterson, M. Rackow, T. |
author_facet |
Bracegirdle, T.J. Holmes, C.R. Hosking, J.S. Marshall, G.J. Osman, Marisol Patterson, M. Rackow, T. |
author_sort |
Bracegirdle, T.J. |
title |
Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP |
title_short |
Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP |
title_full |
Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP |
title_fullStr |
Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP |
title_full_unstemmed |
Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP |
title_sort |
improvements in circumpolar southern hemisphere extratropical atmospheric circulation in cmip6 compared to cmip |
publisher |
Wiley Blackwell Publishing, Inc |
url |
http://hdl.handle.net/11336/144092 |
geographic |
Antarctic Southern Ocean Austral Amundsen Sea |
geographic_facet |
Antarctic Southern Ocean Austral Amundsen Sea |
genre |
Amundsen Sea Antarc* Antarctic British Antarctic Survey Sea ice Southern Ocean |
genre_facet |
Amundsen Sea Antarc* Antarctic British Antarctic Survey Sea ice Southern Ocean |
op_relation |
info:eu-repo/semantics/altIdentifier/url/https://onlinelibrary.wiley.com/doi/abs/10.1029/2019EA001065 info:eu-repo/semantics/altIdentifier/doi/10.1029/2019EA001065 http://hdl.handle.net/11336/144092 Bracegirdle, T.J.; Holmes, C.R.; Hosking, J.S.; Marshall, G.J.; Osman, Marisol; et al.; Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP; Wiley Blackwell Publishing, Inc; Earth and Space Science; 7; 6; 5-2020; 1-25 2333-5084 CONICET Digital CONICET |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/2.5/ar/ |
op_doi |
https://doi.org/10.1029/2019EA001065 |
container_title |
Earth and Space Science |
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7 |
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6 |
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1779310786522382336 |