The association between stratospheric weak polar vortex events and cold air outbreaks in the Northern Hemisphere

By Erik W. Kolstad, Tarjei Breiteig, Adam A. Scaife. 2009

338 citations recorded by the source corpus.

Previous studies have identified an association between temperature anomalies in the Northern Hemisphere and the strength of stratospheric polar westerlies. Large regions in northern Asia, Europe and North America have been found to cool during the mature and late stages of weak vortex events in the stratosphere. A substantial part of the temperature changes are associated with changes in the Northern Annular Mode (NAM) and North Atlantic Oscillation (NAO) pressure patterns in the troposphere. The apparent coupling between the stratosphere and the troposphere may be of relevance for weather forecasting, but only if the temporal and spatial nature of the coupling is known. Using 51 winters of re‐analysis data, we show that the development of the lower‐tropospheric temperature relative to stratospheric weak polar vortex events goes through a series of well‐defined stages, including the formation of geographically distinct cold air outbreaks. At the inception of weak vortex events, a precursor signal in the form of a strong high‐pressure anomaly over northwest Eurasia is associated with long‐lived and robust cold anomalies over Asia and Europe. A few weeks later, near the mature stage of the weak vortex events, a shorter‐lived cold anomaly emerges off the east coast of North America. The probability of cold air outbreaks increases by more than 50% in one or more of these regions during all phases of the weak vortex events. This shows that the stratospheric polar vortex contains information that can be used to enhance forecasts of cold air outbreaks. As large changes in the frequency of extremes are involved, this process is important for the medium‐range and seasonal prediction of extreme cold winter days. Three‐hundred‐year pre‐industrial control simulations by 13 coupled climate models corroborate our results. Copyright © 2010 Royal Meteorological Society and Crown Copyright.

Subfields: Atmospheric Science, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/2dcd35741228ab9e396d2fc1a0d70658f314fccd

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atmospheric Science

In Global and Planetary Change

Citations in the corpus

What Is the Polar Vortex and How Does It Influence Weather (2017, background): “…extremely cold air mass from the polar regions to the midlatitudes at the surface (cold-air outbreaks), and it has been shown that the probability of such events increases following periods when the stratospheric vortex is highly disturbed and weakened (Thompson et al. 2002; Kolstad et al. 2010).”
Downward Arctic Oscillation signal associated with moderate weak stratospheric polar vortex and the cold December 2009 (2010, methodology): “Since a represents the extent to which extreme low temperature events occur [Kolstad et al., 2010], these results suggest that the December in 2009 is characterized by not only lower monthly mean temperature but also more”
Predictability of downward propagation of major sudden stratospheric warmings (2017, background): “Nakagawa and Yamazaki (2006) analysed 51 major and minor SSWs observed during 1952–2002 and noticed that SSWs followed by anomalies propagating into the troposphere were typically initiated by enhanced upward wave flux due to wave-number 2, while the non-propagating cases were characterized by a red”
Sudden Stratospheric Warmings (2020, background): “The negative phase of the NAO is associated with cold air outbreaks (Kolstad et al., 2010; Lehtonen & Karpechko, 2016; King et al., 2019) over Northern Eurasia and the eastern United States, and warm and wet anomalies over Southern Europe (Ayarzag¨uena et al., 2018) due to the southward shift of the”
A new high‐resolution Meteorological Reanalysis Italian Dataset: MERIDA (2019, background): “2019;145:1756–1779. wileyonlinelibrary.com/journal/qj © 2019 Royal Meteorological Society 1756 The mixing of these different types of air mass triggers powerful storms (Fiori et al., 2014), while during winter frequent outbreaks of cold air from northeastern Europe generate deep low-pressure circula”
Seasonal winter forecasts and the stratosphere (2016, background): “Given the stratospheric influence on winter surface climate (e.g. Boville, 1984; Scaife and Knight, 2008; Kolstad et al., 2010; Mitchell et al., 2013; Sigmond et al., 2013), we also investigate the relationship with winter seasonal forecasts of the surface North Atlantic Oscillation (NAO).”
Predicting Sudden Stratospheric Warming 2018 and Its Climate Impacts With a Multimodel Ensemble (2018, background): “Major sudden stratospheric warmings (SSWs), or midwinter episodes of reversal of stratospheric westerly winds, are often followed by periods of anomalous surface weather, in particular, cold air outbreaks in the densely populated regions of western Europe, Far East, and eastern United States (Gar ﬁ ”