Mechanisms and predictability of sudden stratospheric warming in winter 2018
In the beginning of February 2018 a rapid deceleration of the westerly circulation in the polar Northern Hemisphere stratosphere took place, and on 12 February the zonal-mean zonal wind at 60 ∘ N and 10 hPa reversed to easterly in a sudden stratospheric warming (SSW) event. We investigate the role o...
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ftdoajarticles:oai:doaj.org/article:ae3cf7f6bd8f4c0085af6ea3c972525e 2023-05-15T18:41:27+02:00 Mechanisms and predictability of sudden stratospheric warming in winter 2018 I. A. Statnaia A. Y. Karpechko H. J. Järvinen 2020-10-01T00:00:00Z https://doi.org/10.5194/wcd-1-657-2020 https://doaj.org/article/ae3cf7f6bd8f4c0085af6ea3c972525e EN eng Copernicus Publications https://wcd.copernicus.org/articles/1/657/2020/wcd-1-657-2020.pdf https://doaj.org/toc/2698-4016 doi:10.5194/wcd-1-657-2020 2698-4016 https://doaj.org/article/ae3cf7f6bd8f4c0085af6ea3c972525e Weather and Climate Dynamics, Vol 1, Pp 657-674 (2020) Meteorology. Climatology QC851-999 article 2020 ftdoajarticles https://doi.org/10.5194/wcd-1-657-2020 2022-12-31T06:35:47Z In the beginning of February 2018 a rapid deceleration of the westerly circulation in the polar Northern Hemisphere stratosphere took place, and on 12 February the zonal-mean zonal wind at 60 ∘ N and 10 hPa reversed to easterly in a sudden stratospheric warming (SSW) event. We investigate the role of the tropospheric forcing in the occurrence of the SSW, its predictability and teleconnection with the Madden–Julian oscillation (MJO) by analysing the European Centre for Medium-Range Weather Forecasts (ECMWF) ensemble forecast. The SSW was preceded by significant synoptic wave activity over the Pacific and Atlantic basins, which led to the upward propagation of wave packets and resulted in the amplification of a stratospheric wavenumber 2 planetary wave. The dynamical and statistical analyses indicate that the main tropospheric forcing resulted from an anticyclonic Rossby wave breaking, subsequent blocking and upward wave propagation in the Ural Mountains region, in agreement with some previous studies. The ensemble members which predicted the wind reversal also reasonably reproduced this chain of events, from the horizontal propagation of individual wave packets to upward wave-activity fluxes and the amplification of wavenumber 2. On the other hand, the ensemble members which failed to predict the wind reversal also failed to properly capture the blocking event in the key region of the Urals and the associated intensification of upward-propagating wave activity. Finally, a composite analysis suggests that teleconnections associated with the record-breaking MJO phase 6 observed in late January 2018 likely played a role in triggering this SSW event. Article in Journal/Newspaper ural mountains ural mountains Directory of Open Access Journals: DOAJ Articles Pacific Weather and Climate Dynamics 1 2 657 674 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Meteorology. Climatology QC851-999 |
spellingShingle |
Meteorology. Climatology QC851-999 I. A. Statnaia A. Y. Karpechko H. J. Järvinen Mechanisms and predictability of sudden stratospheric warming in winter 2018 |
topic_facet |
Meteorology. Climatology QC851-999 |
description |
In the beginning of February 2018 a rapid deceleration of the westerly circulation in the polar Northern Hemisphere stratosphere took place, and on 12 February the zonal-mean zonal wind at 60 ∘ N and 10 hPa reversed to easterly in a sudden stratospheric warming (SSW) event. We investigate the role of the tropospheric forcing in the occurrence of the SSW, its predictability and teleconnection with the Madden–Julian oscillation (MJO) by analysing the European Centre for Medium-Range Weather Forecasts (ECMWF) ensemble forecast. The SSW was preceded by significant synoptic wave activity over the Pacific and Atlantic basins, which led to the upward propagation of wave packets and resulted in the amplification of a stratospheric wavenumber 2 planetary wave. The dynamical and statistical analyses indicate that the main tropospheric forcing resulted from an anticyclonic Rossby wave breaking, subsequent blocking and upward wave propagation in the Ural Mountains region, in agreement with some previous studies. The ensemble members which predicted the wind reversal also reasonably reproduced this chain of events, from the horizontal propagation of individual wave packets to upward wave-activity fluxes and the amplification of wavenumber 2. On the other hand, the ensemble members which failed to predict the wind reversal also failed to properly capture the blocking event in the key region of the Urals and the associated intensification of upward-propagating wave activity. Finally, a composite analysis suggests that teleconnections associated with the record-breaking MJO phase 6 observed in late January 2018 likely played a role in triggering this SSW event. |
format |
Article in Journal/Newspaper |
author |
I. A. Statnaia A. Y. Karpechko H. J. Järvinen |
author_facet |
I. A. Statnaia A. Y. Karpechko H. J. Järvinen |
author_sort |
I. A. Statnaia |
title |
Mechanisms and predictability of sudden stratospheric warming in winter 2018 |
title_short |
Mechanisms and predictability of sudden stratospheric warming in winter 2018 |
title_full |
Mechanisms and predictability of sudden stratospheric warming in winter 2018 |
title_fullStr |
Mechanisms and predictability of sudden stratospheric warming in winter 2018 |
title_full_unstemmed |
Mechanisms and predictability of sudden stratospheric warming in winter 2018 |
title_sort |
mechanisms and predictability of sudden stratospheric warming in winter 2018 |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/wcd-1-657-2020 https://doaj.org/article/ae3cf7f6bd8f4c0085af6ea3c972525e |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
ural mountains ural mountains |
genre_facet |
ural mountains ural mountains |
op_source |
Weather and Climate Dynamics, Vol 1, Pp 657-674 (2020) |
op_relation |
https://wcd.copernicus.org/articles/1/657/2020/wcd-1-657-2020.pdf https://doaj.org/toc/2698-4016 doi:10.5194/wcd-1-657-2020 2698-4016 https://doaj.org/article/ae3cf7f6bd8f4c0085af6ea3c972525e |
op_doi |
https://doi.org/10.5194/wcd-1-657-2020 |
container_title |
Weather and Climate Dynamics |
container_volume |
1 |
container_issue |
2 |
container_start_page |
657 |
op_container_end_page |
674 |
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