Extreme stratospheric wave activity as harbingers of cold events over North America
Open access
Date
2023-05-27Type
- Journal Article
Abstract
Extreme cold events over North America such as the February 2021 cold wave have been suggested to be linked to stratospheric polar vortex stretching. However, it is not resolved how robustly and on which timescales the stratosphere contributes to the surface anomalies. Here we introduce a simple measure of stratospheric wave activity for reanalyses and model outputs. In contrast to the well-known surface influences of sudden stratospheric warmings (SSWs) that increase the intraseasonal persistence of weather regimes, we show that extreme stratospheric wave events are accompanied by intraseasonal fluctuations between warm and cold spells over North America in observations and climate models. Particularly, strong stratospheric wave events are followed by an increased risk of cold extremes over North America 5–25 days later. Idealized simulations in an atmospheric model with a well-resolved stratosphere corroborate that strong stratospheric wave activity precedes North American cold spells through vertical wave coupling. These findings potentially benefit the predictability of high-impact winter cold extremes over North America. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000615030Publication status
publishedExternal links
Journal / series
Communications Earth & EnvironmentVolume
Pages / Article No.
Publisher
SpringerOrganisational unit
09612 - Domeisen, Daniela / Domeisen, Daniela
Funding
198896 - Remote Drivers of Extreme Temperature Events (SNF)
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