Titre
Opposite spectral properties of Rossby waves during weak and strong stratospheric polar vortex events
Type
article
Institution
UNIL/CHUV/Unisanté + institutions partenaires
Périodique
Auteur(s)
Schutte, Michael
Auteure/Auteur
Domeisen, Daniela I. V.
Auteure/Auteur
Riboldi, Jacopo
Auteure/Auteur
Liens vers les personnes
Liens vers les unités
Statut éditorial
Publié
Date de publication
2024-05-08
Volume
5
Première page
733–752
Peer-reviewed
Oui
Langue
anglais
Résumé
In this study we provide a systematic characterization of Rossby wave activity during the 25 sudden stratospheric warming (SSW) and 31 strong polar vortex (SPV) events that occurred in the period 1979–2021, identifying the specific tropospheric and stratospheric waves displaying anomalous behaviour during such events. Space–time spectral analysis is applied to ERA5 data for this purpose, so that both the wavenumber and the zonal phase speed of the waves can be assessed. We find that SSW events are associated with a reduction in the phase speed of Rossby waves, first in the stratosphere and then in the troposphere; SPV events are tied to a simultaneous increase of phase speed across vertical levels. Phase speed anomalies become significant around the event and persist for 2–3 weeks afterwards. Changes of Rossby wave properties in the stratosphere during SSW and SPV events are dominated by changes in the background flow, with a systematic reduction or increase, respectively, in eastward propagation of the waves across most wavenumbers. In the troposphere, on the other hand, the effect of the background flow is also complemented by changes in wave properties, with a shift towards higher wavenumbers during SSW events and towards lower wavenumbers for SPV events. The opposite response between SSW and SPV events is also visible in the meridional heat and momentum flux co-spectra, which highlight from a novel perspective the connection between stratospheric Rossby waves and upward propagation of waves.
PID Serval
serval:BIB_BC1178AF64E3
URL éditeur
Date de création
2024-10-31T22:19:10.162Z
Date de création dans IRIS
2025-05-20T21:42:46Z
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Nom
wcd-5-733-2024.pdf
Version du manuscrit
published
Licence
https://creativecommons.org/licenses/by/4.0
Taille
2.19 MB
Format
Adobe PDF
PID Serval
serval:BIB_BC1178AF64E3.P001
URN
urn:nbn:ch:serval-BIB_BC1178AF64E32
Somme de contrôle
(MD5):22ca1f0dc8c314fc89567bf4a62b34e9