Using large ensembles to quantify the impact of sudden stratospheric warmings and their precursors on the North Atlantic Oscillation
-
Published:2023-02-23
Issue:1
Volume:4
Page:213-228
-
ISSN:2698-4016
-
Container-title:Weather and Climate Dynamics
-
language:en
-
Short-container-title:Weather Clim. Dynam.
Author:
Bett Philip E.ORCID, Scaife Adam A.ORCID, Hardiman Steven C.ORCID, Thornton Hazel E., Shen Xiaocen, Wang LinORCID, Pang Bo
Abstract
Abstract. Sudden-stratospheric-warming (SSW) events are often followed by significant weather and climate impacts at the surface. By affecting the North Atlantic Oscillation (NAO), SSWs can lead to periods of extreme cold in parts of Europe and North America. Previous studies have used observations and free-running climate models to try to identify features of the atmosphere prior to an SSW that can determine the subsequent impact at the surface. However, the limited observational record makes it difficult to accurately quantify these relationships. Here, we instead use a large
ensemble of seasonal hindcasts. We first test whether the hindcasts reproduce the observed characteristics of SSWs and their surface signature. We find that the simulations are statistically indistinguishable from the observations, in terms of the overall risk of an SSW per winter (56 %), the frequency of SSWs with negative NAO responses (65 %), the magnitude of the NAO responses, and the frequency of wavenumber-2-dominated SSWs
(26 %). We also assess the relationships between prior conditions and the NAO response in the 30 d following an SSW. We find that there
is little information in the precursor state to guide differences in the subsequent NAO behaviour between one SSW and another, reflecting the
substantial natural variability between SSW events. The strongest relationships with the NAO response are from pre-SSW sea level pressure anomalies over the polar cap and from zonal-wind anomalies in the lower stratosphere, both exhibiting correlations of around 0.3. The pre-SSW NAO has little bearing on its post-SSW state. The strength of the pre-SSW zonal-wind anomalies at 10 hPa is also not significantly correlated with the NAO response. Finally, we find that the mean NAO response in the first 10 d following wave-2-dominated SSWs is much more strongly negative than in wave-1 cases. However, the subsequent response in days 11–30 is very similar regardless of the dominant wavenumber. In all cases, the composite mean responses are the result of very broad distributions from individual SSW events, necessitating a probabilistic analysis using large ensembles.
Funder
Newton Fund Department for Business, Energy and Industrial Strategy, UK Government
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference84 articles.
1. Anstey, J. A. and Shepherd, T. G.: High-latitude influence of the quasi-biennial oscillation, Q. J. Roy. Meteor. Soc., 140, 1–21, https://doi.org/10.1002/qj.2132, 2014. 2. Baldwin, M. P. and Dunkerton, T. J.:
Propagation of the Arctic Oscillation from the stratosphere to the troposphere, J. Geophys. Res.-Atmos., 104, 30937–30946, https://doi.org/10.1029/1999JD900445, 1999. 3. Baldwin, M. P. and Dunkerton, T. J.:
Stratospheric harbingers of anomalous weather regimes, Science (80-), 294, 581–584, https://doi.org/10.1126/science.1063315, 2001. 4. Baldwin, M. P., Ayarzagüena, B., Birner, T., Butchart, N., Butler, A. H., Charlton-Perez, A. J., Domeisen, D. I. V., Garfinkel, C. I., Garny, H., Gerber, E. P., Hegglin, M. I., Langematz, U., and Pedatella, N. M.:
Sudden Stratospheric Warmings, Rev. Geophys., 59, e2020RG000708, https://doi.org/10.1029/2020RG000708, 2021. 5. Bancalá, S., Krüger, K., and Giorgetta, M.:
The preconditioning of major sudden stratospheric warmings, J. Geophys. Res.-Atmos., 117, 4101, https://doi.org/10.1029/2011JD016769, 2012.
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|