The Stratospheric Pathway of La Niña

A Northern Hemisphere (NH) polar stratospheric pathway for La Nina events is established during wintertime based on reanalysis data for the 1958-2012 period. A robust polar stratospheric response is observed in the NH during strong La Nina events, characterized by a significantly stronger and cooler...

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Detalles Bibliográficos
Autores: Iza San Juan, Maddalen, Calvo Fernández, Natalia, Manzini, Elisa
Tipo de recurso: artículo
Fecha de publicación:2016
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/17597
Acceso en línea:https://hdl.handle.net/20.500.14352/17597
Access Level:acceso abierto
Palabra clave:52
El niño
Southern-oscillation
Sudden warmings
North-Atlantic
Polar vortex
Winter
Reanalysis
Events
Enso
Teleconnections
Astrofísica
Astronomía (Física)
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repository_id_str
spelling The Stratospheric Pathway of La NiñaIza San Juan, MaddalenCalvo Fernández, NataliaManzini, Elisa52El niñoSouthern-oscillationSudden warmingsNorth-AtlanticPolar vortexWinterReanalysisEventsEnsoTeleconnectionsAstrofísicaAstronomía (Física)A Northern Hemisphere (NH) polar stratospheric pathway for La Nina events is established during wintertime based on reanalysis data for the 1958-2012 period. A robust polar stratospheric response is observed in the NH during strong La Nina events, characterized by a significantly stronger and cooler polar vortex. Significant wind anomalies reach the surface, and a robust impact on the North Atlantic-European (NAE) region is observed. A dynamical analysis reveals that the stronger polar stratospheric winds during La Nina winters are due to reduced upward planetary wave activity into the stratosphere. This finding is the result of destructive interference between the climatological and the anomalous La Nina tropospheric stationary eddies over the Pacific-North American region. In addition, the lack of a robust stratospheric signature during La Nina winters reported in previous studies is investigated. It is found that this is related to the lower threshold used to detect the events, which signature is consequently more prone to be obscured by the influence of other sources of variability. In particular, the occurrence of stratospheric sudden warmings (SSWs), partly linked to the phase of the quasi-biennial oscillation, modulates the observed stratospheric signal. In the case of La Nina winters defined by a lower threshold, a robust stratospheric cooling is found only in the absence of SSWs. Therefore, these results highlight the importance of using a relatively restrictive threshold to define La Nina events in order to obtain a robust surface response in the NAE region through the stratosphere.American Meteorological SocietyUniversidad Complutense de Madrid20162016-12-0120162016-12-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/17597reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/175972026-06-02T12:44:21Z
dc.title.none.fl_str_mv The Stratospheric Pathway of La Niña
title The Stratospheric Pathway of La Niña
spellingShingle The Stratospheric Pathway of La Niña
Iza San Juan, Maddalen
52
El niño
Southern-oscillation
Sudden warmings
North-Atlantic
Polar vortex
Winter
Reanalysis
Events
Enso
Teleconnections
Astrofísica
Astronomía (Física)
title_short The Stratospheric Pathway of La Niña
title_full The Stratospheric Pathway of La Niña
title_fullStr The Stratospheric Pathway of La Niña
title_full_unstemmed The Stratospheric Pathway of La Niña
title_sort The Stratospheric Pathway of La Niña
dc.creator.none.fl_str_mv Iza San Juan, Maddalen
Calvo Fernández, Natalia
Manzini, Elisa
author Iza San Juan, Maddalen
author_facet Iza San Juan, Maddalen
Calvo Fernández, Natalia
Manzini, Elisa
author_role author
author2 Calvo Fernández, Natalia
Manzini, Elisa
author2_role author
author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 52
El niño
Southern-oscillation
Sudden warmings
North-Atlantic
Polar vortex
Winter
Reanalysis
Events
Enso
Teleconnections
Astrofísica
Astronomía (Física)
topic 52
El niño
Southern-oscillation
Sudden warmings
North-Atlantic
Polar vortex
Winter
Reanalysis
Events
Enso
Teleconnections
Astrofísica
Astronomía (Física)
description A Northern Hemisphere (NH) polar stratospheric pathway for La Nina events is established during wintertime based on reanalysis data for the 1958-2012 period. A robust polar stratospheric response is observed in the NH during strong La Nina events, characterized by a significantly stronger and cooler polar vortex. Significant wind anomalies reach the surface, and a robust impact on the North Atlantic-European (NAE) region is observed. A dynamical analysis reveals that the stronger polar stratospheric winds during La Nina winters are due to reduced upward planetary wave activity into the stratosphere. This finding is the result of destructive interference between the climatological and the anomalous La Nina tropospheric stationary eddies over the Pacific-North American region. In addition, the lack of a robust stratospheric signature during La Nina winters reported in previous studies is investigated. It is found that this is related to the lower threshold used to detect the events, which signature is consequently more prone to be obscured by the influence of other sources of variability. In particular, the occurrence of stratospheric sudden warmings (SSWs), partly linked to the phase of the quasi-biennial oscillation, modulates the observed stratospheric signal. In the case of La Nina winters defined by a lower threshold, a robust stratospheric cooling is found only in the absence of SSWs. Therefore, these results highlight the importance of using a relatively restrictive threshold to define La Nina events in order to obtain a robust surface response in the NAE region through the stratosphere.
publishDate 2016
dc.date.none.fl_str_mv 2016
2016-12-01
2016
2016-12-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/20.500.14352/17597
url https://hdl.handle.net/20.500.14352/17597
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv American Meteorological Society
publisher.none.fl_str_mv American Meteorological Society
dc.source.none.fl_str_mv reponame:Docta Complutense
instname:Universidad Complutense de Madrid (UCM)
instname_str Universidad Complutense de Madrid (UCM)
reponame_str Docta Complutense
collection Docta Complutense
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,300724

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