More-persistent weak stratospheric polar vortex states linked to cold extremes
The extratropical stratosphere in boreal winter is characterized by a strong circumpolar westerly jet, confining the coldest temperatures at high latitudes. The jet, referred to as the stratospheric polar vortex, is predominantly zonal and centered around the pole; however, it does exhibit large var...
Published in: | Bulletin of the American Meteorological Society |
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ftpotsdamik:oai:publications.pik-potsdam.de:item_21717 2023-10-29T02:34:25+01:00 More-persistent weak stratospheric polar vortex states linked to cold extremes Kretschmer, M. Coumou, D. Agel, L. Barlow, M. Tziperman, E. Cohen, J. 2018 application/pdf https://publications.pik-potsdam.de/pubman/item/item_21717 https://publications.pik-potsdam.de/pubman/item/item_21717_1/component/file_21718/7653oa.pdf unknown info:eu-repo/semantics/altIdentifier/doi/10.1175/BAMS-D-16-0259.1 https://publications.pik-potsdam.de/pubman/item/item_21717 https://publications.pik-potsdam.de/pubman/item/item_21717_1/component/file_21718/7653oa.pdf info:eu-repo/semantics/openAccess Bulletin of the American Meteorological Society info:eu-repo/semantics/article 2018 ftpotsdamik https://doi.org/10.1175/BAMS-D-16-0259.1 2023-09-30T17:59:39Z The extratropical stratosphere in boreal winter is characterized by a strong circumpolar westerly jet, confining the coldest temperatures at high latitudes. The jet, referred to as the stratospheric polar vortex, is predominantly zonal and centered around the pole; however, it does exhibit large variability in wind speed and location. Previous studies showed that a weak stratospheric polar vortex can lead to cold-air outbreaks in the midlatitudes, but the exact relationships and mechanisms are unclear. Particularly, it is unclear whether stratospheric variability has contributed to the observed anomalous cooling trends in midlatitude Eurasia. Using hierarchical clustering, we show that over the last 37 years, the frequency of weak vortex states in mid- to late winter (January and February) has increased, which was accompanied by subsequent cold extremes in midlatitude Eurasia. For this region, 60% of the observed cooling in the era of Arctic amplification, that is, since 1990, can be explained by the increased frequency of weak stratospheric polar vortex states, a number that increases to almost 80% when El Niño–Southern Oscillation (ENSO) variability is included as well. Article in Journal/Newspaper Arctic Publication Database PIK (Potsdam Institute for Climate Impact Research) Bulletin of the American Meteorological Society 99 1 49 60 |
institution |
Open Polar |
collection |
Publication Database PIK (Potsdam Institute for Climate Impact Research) |
op_collection_id |
ftpotsdamik |
language |
unknown |
description |
The extratropical stratosphere in boreal winter is characterized by a strong circumpolar westerly jet, confining the coldest temperatures at high latitudes. The jet, referred to as the stratospheric polar vortex, is predominantly zonal and centered around the pole; however, it does exhibit large variability in wind speed and location. Previous studies showed that a weak stratospheric polar vortex can lead to cold-air outbreaks in the midlatitudes, but the exact relationships and mechanisms are unclear. Particularly, it is unclear whether stratospheric variability has contributed to the observed anomalous cooling trends in midlatitude Eurasia. Using hierarchical clustering, we show that over the last 37 years, the frequency of weak vortex states in mid- to late winter (January and February) has increased, which was accompanied by subsequent cold extremes in midlatitude Eurasia. For this region, 60% of the observed cooling in the era of Arctic amplification, that is, since 1990, can be explained by the increased frequency of weak stratospheric polar vortex states, a number that increases to almost 80% when El Niño–Southern Oscillation (ENSO) variability is included as well. |
format |
Article in Journal/Newspaper |
author |
Kretschmer, M. Coumou, D. Agel, L. Barlow, M. Tziperman, E. Cohen, J. |
spellingShingle |
Kretschmer, M. Coumou, D. Agel, L. Barlow, M. Tziperman, E. Cohen, J. More-persistent weak stratospheric polar vortex states linked to cold extremes |
author_facet |
Kretschmer, M. Coumou, D. Agel, L. Barlow, M. Tziperman, E. Cohen, J. |
author_sort |
Kretschmer, M. |
title |
More-persistent weak stratospheric polar vortex states linked to cold extremes |
title_short |
More-persistent weak stratospheric polar vortex states linked to cold extremes |
title_full |
More-persistent weak stratospheric polar vortex states linked to cold extremes |
title_fullStr |
More-persistent weak stratospheric polar vortex states linked to cold extremes |
title_full_unstemmed |
More-persistent weak stratospheric polar vortex states linked to cold extremes |
title_sort |
more-persistent weak stratospheric polar vortex states linked to cold extremes |
publishDate |
2018 |
url |
https://publications.pik-potsdam.de/pubman/item/item_21717 https://publications.pik-potsdam.de/pubman/item/item_21717_1/component/file_21718/7653oa.pdf |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Bulletin of the American Meteorological Society |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/BAMS-D-16-0259.1 https://publications.pik-potsdam.de/pubman/item/item_21717 https://publications.pik-potsdam.de/pubman/item/item_21717_1/component/file_21718/7653oa.pdf |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/BAMS-D-16-0259.1 |
container_title |
Bulletin of the American Meteorological Society |
container_volume |
99 |
container_issue |
1 |
container_start_page |
49 |
op_container_end_page |
60 |
_version_ |
1781057016657084416 |