The different stratospheric influence on cold-extremes in Eurasia and North America
The stratospheric polar vortex can influence the tropospheric circulation and thereby winter weather in the mid-latitudes. Weak vortex states, often associated with sudden stratospheric warmings (SSW), have been shown to increase the risk of cold-spells especially over Eurasia, but its role for Nort...
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fttibhannoverren:oai:oa.tib.eu:123456789/11328 2024-09-15T18:24:04+00:00 The different stratospheric influence on cold-extremes in Eurasia and North America Kretschmer, Marlene Cohen, Judah Matthias, Vivien Runge, Jakob Coumou, Dim 2018 application/pdf https://oa.tib.eu/renate/handle/123456789/11328 https://doi.org/10.34657/10363 eng eng London : Springer Nature ESSN:2397-3722 DOI:https://doi.org/10.1038/s41612-018-0054-4 https://oa.tib.eu/renate/handle/123456789/11328 http://dx.doi.org/10.34657/10363 CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0 frei zugänglich ddc:333.7 ddc:530 atmospheric circulation cold wave extreme event midlatitude environment polar vortex stratosphere sudden stratospheric warming winter status-type:publishedVersion doc-type:Article doc-type:Text 2018 fttibhannoverren https://doi.org/10.34657/1036310.1038/s41612-018-0054-4 2024-07-03T23:33:52Z The stratospheric polar vortex can influence the tropospheric circulation and thereby winter weather in the mid-latitudes. Weak vortex states, often associated with sudden stratospheric warmings (SSW), have been shown to increase the risk of cold-spells especially over Eurasia, but its role for North American winters is less clear. Using cluster analysis, we show that there are two dominant patterns of increased polar cap heights in the lower stratosphere. Both patterns represent a weak polar vortex but they are associated with different wave mechanisms and different regional tropospheric impacts. The first pattern is zonally symmetric and associated with absorbed upward-propagating wave activity, leading to a negative phase of the North Atlantic Oscillation (NAO) and cold-air outbreaks over northern Eurasia. This coupling mechanism is well-documented in the literature and is consistent with the downward migration of the northern annular mode (NAM). The second pattern is zonally asymmetric and linked to downward reflected planetary waves over Canada followed by a negative phase of the Western Pacific Oscillation (WPO) and cold-spells in Central Canada and the Great Lakes region. Causal effect network (CEN) analyses confirm the atmospheric pathways associated with this asymmetric pattern. Moreover, our findings suggest the reflective mechanism to be sensitive to the exact region of upward wave-activity fluxes and to be state-dependent on the strength of the vortex. Identifying the causal pathways that operate on weekly to monthly timescales can pave the way for improved sub-seasonal to seasonal forecasting of cold spells in the mid-latitudes. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover) |
institution |
Open Polar |
collection |
Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover) |
op_collection_id |
fttibhannoverren |
language |
English |
topic |
ddc:333.7 ddc:530 atmospheric circulation cold wave extreme event midlatitude environment polar vortex stratosphere sudden stratospheric warming winter |
spellingShingle |
ddc:333.7 ddc:530 atmospheric circulation cold wave extreme event midlatitude environment polar vortex stratosphere sudden stratospheric warming winter Kretschmer, Marlene Cohen, Judah Matthias, Vivien Runge, Jakob Coumou, Dim The different stratospheric influence on cold-extremes in Eurasia and North America |
topic_facet |
ddc:333.7 ddc:530 atmospheric circulation cold wave extreme event midlatitude environment polar vortex stratosphere sudden stratospheric warming winter |
description |
The stratospheric polar vortex can influence the tropospheric circulation and thereby winter weather in the mid-latitudes. Weak vortex states, often associated with sudden stratospheric warmings (SSW), have been shown to increase the risk of cold-spells especially over Eurasia, but its role for North American winters is less clear. Using cluster analysis, we show that there are two dominant patterns of increased polar cap heights in the lower stratosphere. Both patterns represent a weak polar vortex but they are associated with different wave mechanisms and different regional tropospheric impacts. The first pattern is zonally symmetric and associated with absorbed upward-propagating wave activity, leading to a negative phase of the North Atlantic Oscillation (NAO) and cold-air outbreaks over northern Eurasia. This coupling mechanism is well-documented in the literature and is consistent with the downward migration of the northern annular mode (NAM). The second pattern is zonally asymmetric and linked to downward reflected planetary waves over Canada followed by a negative phase of the Western Pacific Oscillation (WPO) and cold-spells in Central Canada and the Great Lakes region. Causal effect network (CEN) analyses confirm the atmospheric pathways associated with this asymmetric pattern. Moreover, our findings suggest the reflective mechanism to be sensitive to the exact region of upward wave-activity fluxes and to be state-dependent on the strength of the vortex. Identifying the causal pathways that operate on weekly to monthly timescales can pave the way for improved sub-seasonal to seasonal forecasting of cold spells in the mid-latitudes. |
format |
Article in Journal/Newspaper |
author |
Kretschmer, Marlene Cohen, Judah Matthias, Vivien Runge, Jakob Coumou, Dim |
author_facet |
Kretschmer, Marlene Cohen, Judah Matthias, Vivien Runge, Jakob Coumou, Dim |
author_sort |
Kretschmer, Marlene |
title |
The different stratospheric influence on cold-extremes in Eurasia and North America |
title_short |
The different stratospheric influence on cold-extremes in Eurasia and North America |
title_full |
The different stratospheric influence on cold-extremes in Eurasia and North America |
title_fullStr |
The different stratospheric influence on cold-extremes in Eurasia and North America |
title_full_unstemmed |
The different stratospheric influence on cold-extremes in Eurasia and North America |
title_sort |
different stratospheric influence on cold-extremes in eurasia and north america |
publisher |
London : Springer Nature |
publishDate |
2018 |
url |
https://oa.tib.eu/renate/handle/123456789/11328 https://doi.org/10.34657/10363 |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
ESSN:2397-3722 DOI:https://doi.org/10.1038/s41612-018-0054-4 https://oa.tib.eu/renate/handle/123456789/11328 http://dx.doi.org/10.34657/10363 |
op_rights |
CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0 frei zugänglich |
op_doi |
https://doi.org/10.34657/1036310.1038/s41612-018-0054-4 |
_version_ |
1810464369004249088 |