Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models
Extreme events in the stratospheric polar vortex can lead to changes in the tropospheric circulation and impact the surface climate on a wide range of timescales. The austral stratospheric vortex shows its largest variability in spring, and a weakened polar vortex is associated with changes in the s...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/584640 2023-05-15T13:41:37+02:00 Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models Bergner, Nora Friedel, Marina Domeisen, Daniela Waugh, Darryn Chiodo, Gabriel 2022 application/application/pdf https://hdl.handle.net/20.500.11850/584640 https://doi.org/10.3929/ethz-b-000584640 en eng Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/acp-22-13915-2022 info:eu-repo/grantAgreement/SNF/Ambizione/180043 info:eu-repo/grantAgreement/SNF/SNF-Förderungsprofessuren: Fortsetzungsgesuche/198896 http://hdl.handle.net/20.500.11850/584640 doi:10.3929/ethz-b-000584640 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International CC-BY Atmospheric Chemistry and Physics, 22 (21) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2022 ftethz https://doi.org/20.500.11850/584640 https://doi.org/10.3929/ethz-b-000584640 https://doi.org/10.5194/acp-22-13915-2022 2023-02-13T01:15:53Z Extreme events in the stratospheric polar vortex can lead to changes in the tropospheric circulation and impact the surface climate on a wide range of timescales. The austral stratospheric vortex shows its largest variability in spring, and a weakened polar vortex is associated with changes in the spring to summer surface climate, including hot and dry extremes in Australia. However, the robustness and extent of the connection between polar vortex strength and surface climate on interannual timescales remain unclear. We assess this relationship by using reanalysis data and time-slice simulations from two chemistry-climate models (CCMs), building on previous work that is mainly based on observations. The CCMs show a similar downward propagation of anomalies in the polar vortex strength to the reanalysis data: a weak polar vortex is on average followed by a negative tropospheric Southern Annular Mode (SAM) in spring to summer, while a strong polar vortex is on average followed by a positive SAM. The signature in the surface climate following polar vortex weakenings is characterized by high surface pressure and warm temperature anomalies over Antarctica, the region where surface signals are most robust across all model and observational datasets. However, the tropospheric SAM response in the two CCMs considered is inconsistent with observations. In one CCM, the SAM is more negative compared to the reanalysis after weak polar vortex events, whereas in the other CCM, it is less negative. In addition, neither model reproduces all the regional changes in midlatitudes, such as the warm and dry anomalies over Australia. We find that these inconsistencies are linked to model biases in the basic state, such as the latitude of the eddy-driven jet and the persistence of the SAM. These results are largely corroborated by models that participated in the Chemistry-Climate Model Initiative (CCMI). Furthermore, bootstrapping of the data reveals sizable uncertainty in the magnitude of the surface signals in both models and ... Article in Journal/Newspaper Antarc* Antarctica ETH Zürich Research Collection Austral |
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Open Polar |
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ETH Zürich Research Collection |
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ftethz |
language |
English |
description |
Extreme events in the stratospheric polar vortex can lead to changes in the tropospheric circulation and impact the surface climate on a wide range of timescales. The austral stratospheric vortex shows its largest variability in spring, and a weakened polar vortex is associated with changes in the spring to summer surface climate, including hot and dry extremes in Australia. However, the robustness and extent of the connection between polar vortex strength and surface climate on interannual timescales remain unclear. We assess this relationship by using reanalysis data and time-slice simulations from two chemistry-climate models (CCMs), building on previous work that is mainly based on observations. The CCMs show a similar downward propagation of anomalies in the polar vortex strength to the reanalysis data: a weak polar vortex is on average followed by a negative tropospheric Southern Annular Mode (SAM) in spring to summer, while a strong polar vortex is on average followed by a positive SAM. The signature in the surface climate following polar vortex weakenings is characterized by high surface pressure and warm temperature anomalies over Antarctica, the region where surface signals are most robust across all model and observational datasets. However, the tropospheric SAM response in the two CCMs considered is inconsistent with observations. In one CCM, the SAM is more negative compared to the reanalysis after weak polar vortex events, whereas in the other CCM, it is less negative. In addition, neither model reproduces all the regional changes in midlatitudes, such as the warm and dry anomalies over Australia. We find that these inconsistencies are linked to model biases in the basic state, such as the latitude of the eddy-driven jet and the persistence of the SAM. These results are largely corroborated by models that participated in the Chemistry-Climate Model Initiative (CCMI). Furthermore, bootstrapping of the data reveals sizable uncertainty in the magnitude of the surface signals in both models and ... |
format |
Article in Journal/Newspaper |
author |
Bergner, Nora Friedel, Marina Domeisen, Daniela Waugh, Darryn Chiodo, Gabriel |
spellingShingle |
Bergner, Nora Friedel, Marina Domeisen, Daniela Waugh, Darryn Chiodo, Gabriel Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models |
author_facet |
Bergner, Nora Friedel, Marina Domeisen, Daniela Waugh, Darryn Chiodo, Gabriel |
author_sort |
Bergner, Nora |
title |
Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models |
title_short |
Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models |
title_full |
Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models |
title_fullStr |
Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models |
title_full_unstemmed |
Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models |
title_sort |
exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models |
publisher |
Copernicus |
publishDate |
2022 |
url |
https://hdl.handle.net/20.500.11850/584640 https://doi.org/10.3929/ethz-b-000584640 |
geographic |
Austral |
geographic_facet |
Austral |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_source |
Atmospheric Chemistry and Physics, 22 (21) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/acp-22-13915-2022 info:eu-repo/grantAgreement/SNF/Ambizione/180043 info:eu-repo/grantAgreement/SNF/SNF-Förderungsprofessuren: Fortsetzungsgesuche/198896 http://hdl.handle.net/20.500.11850/584640 doi:10.3929/ethz-b-000584640 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/20.500.11850/584640 https://doi.org/10.3929/ethz-b-000584640 https://doi.org/10.5194/acp-22-13915-2022 |
_version_ |
1766153065351610368 |