The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts
This study offers an overview of the low-frequency (i.e., monthly to seasonal) evolution, dynamics, predictability, and surface impacts of a rare Southern Hemisphere (SH) stratospheric warming that occurred in austral spring 2019. Between late August and mid-September 2019, the stratospheric circump...
Published in: | Bulletin of the American Meteorological Society |
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ftuniveastangl:oai:ueaeprints.uea.ac.uk:85511 2023-05-15T14:02:10+02:00 The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts Lim, Eun-Pa Hendon, Harry H. Butler, Amy H. Thompson, David W. J. Lawrence, Zachary D. Scaife, Adam A. Shepherd, Theodore G. Polichtchouk, Inna Nakamura, Hisashi Kobayashi, Chiaki Comer, Ruth Coy, Lawrence Dowdy, Andrew Garreaud, Rene D. Newman, Paul A. Wang, Guomin 2021-06 application/pdf https://ueaeprints.uea.ac.uk/id/eprint/85511/ https://ueaeprints.uea.ac.uk/id/eprint/85511/1/_15200477_Bulletin_of_the_American_Meteorological_Society_The_2019_Southern_Hemisphere_Stratospheric_Polar_Vortex_Weakening_and_Its_Impacts.pdf https://doi.org/10.1175/BAMS-D-20-0112.1 en eng https://ueaeprints.uea.ac.uk/id/eprint/85511/1/_15200477_Bulletin_of_the_American_Meteorological_Society_The_2019_Southern_Hemisphere_Stratospheric_Polar_Vortex_Weakening_and_Its_Impacts.pdf Lim, Eun-Pa, Hendon, Harry H., Butler, Amy H., Thompson, David W. J., Lawrence, Zachary D., Scaife, Adam A., Shepherd, Theodore G., Polichtchouk, Inna, Nakamura, Hisashi, Kobayashi, Chiaki, Comer, Ruth, Coy, Lawrence, Dowdy, Andrew, Garreaud, Rene D., Newman, Paul A. and Wang, Guomin (2021) The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts. Bulletin of the American Meteorological Society, 102 (6). E1150–E1171. ISSN 0003-0007 doi:10.1175/BAMS-D-20-0112.1 Article PeerReviewed 2021 ftuniveastangl https://doi.org/10.1175/BAMS-D-20-0112.1 2023-01-30T21:57:14Z This study offers an overview of the low-frequency (i.e., monthly to seasonal) evolution, dynamics, predictability, and surface impacts of a rare Southern Hemisphere (SH) stratospheric warming that occurred in austral spring 2019. Between late August and mid-September 2019, the stratospheric circumpolar westerly jet weakened rapidly, and Antarctic stratospheric temperatures rose dramatically. The deceleration of the vortex at 10 hPa was as drastic as that of the first-ever-observed major sudden stratospheric warming in the SH during 2002, while the mean Antarctic warming over the course of spring 2019 broke the previous record of 2002 by ∼50% in the midstratosphere. This event was preceded by a poleward shift of the SH polar night jet in the uppermost stratosphere in early winter, which was then followed by record-strong planetary wave-1 activity propagating upward from the troposphere in August that acted to dramatically weaken the polar vortex throughout the depth of the stratosphere. The weakened vortex winds and elevated temperatures moved downward to the surface from mid-October to December, promoting a record strong swing of the southern annular mode (SAM) to its negative phase. This record-negative SAM appeared to be a primary driver of the extreme hot and dry conditions over subtropical eastern Australia that accompanied the severe wildfires that occurred in late spring 2019. State-of-the-art dynamical seasonal forecast systems skillfully predicted the significant vortex weakening of spring 2019 and subsequent development of negative SAM from as early as late July. Article in Journal/Newspaper Antarc* Antarctic polar night University of East Anglia: UEA Digital Repository Antarctic Austral Bulletin of the American Meteorological Society 102 6 E1150 E1171 |
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Open Polar |
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University of East Anglia: UEA Digital Repository |
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ftuniveastangl |
language |
English |
description |
This study offers an overview of the low-frequency (i.e., monthly to seasonal) evolution, dynamics, predictability, and surface impacts of a rare Southern Hemisphere (SH) stratospheric warming that occurred in austral spring 2019. Between late August and mid-September 2019, the stratospheric circumpolar westerly jet weakened rapidly, and Antarctic stratospheric temperatures rose dramatically. The deceleration of the vortex at 10 hPa was as drastic as that of the first-ever-observed major sudden stratospheric warming in the SH during 2002, while the mean Antarctic warming over the course of spring 2019 broke the previous record of 2002 by ∼50% in the midstratosphere. This event was preceded by a poleward shift of the SH polar night jet in the uppermost stratosphere in early winter, which was then followed by record-strong planetary wave-1 activity propagating upward from the troposphere in August that acted to dramatically weaken the polar vortex throughout the depth of the stratosphere. The weakened vortex winds and elevated temperatures moved downward to the surface from mid-October to December, promoting a record strong swing of the southern annular mode (SAM) to its negative phase. This record-negative SAM appeared to be a primary driver of the extreme hot and dry conditions over subtropical eastern Australia that accompanied the severe wildfires that occurred in late spring 2019. State-of-the-art dynamical seasonal forecast systems skillfully predicted the significant vortex weakening of spring 2019 and subsequent development of negative SAM from as early as late July. |
format |
Article in Journal/Newspaper |
author |
Lim, Eun-Pa Hendon, Harry H. Butler, Amy H. Thompson, David W. J. Lawrence, Zachary D. Scaife, Adam A. Shepherd, Theodore G. Polichtchouk, Inna Nakamura, Hisashi Kobayashi, Chiaki Comer, Ruth Coy, Lawrence Dowdy, Andrew Garreaud, Rene D. Newman, Paul A. Wang, Guomin |
spellingShingle |
Lim, Eun-Pa Hendon, Harry H. Butler, Amy H. Thompson, David W. J. Lawrence, Zachary D. Scaife, Adam A. Shepherd, Theodore G. Polichtchouk, Inna Nakamura, Hisashi Kobayashi, Chiaki Comer, Ruth Coy, Lawrence Dowdy, Andrew Garreaud, Rene D. Newman, Paul A. Wang, Guomin The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts |
author_facet |
Lim, Eun-Pa Hendon, Harry H. Butler, Amy H. Thompson, David W. J. Lawrence, Zachary D. Scaife, Adam A. Shepherd, Theodore G. Polichtchouk, Inna Nakamura, Hisashi Kobayashi, Chiaki Comer, Ruth Coy, Lawrence Dowdy, Andrew Garreaud, Rene D. Newman, Paul A. Wang, Guomin |
author_sort |
Lim, Eun-Pa |
title |
The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts |
title_short |
The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts |
title_full |
The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts |
title_fullStr |
The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts |
title_full_unstemmed |
The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts |
title_sort |
2019 southern hemisphere stratospheric polar vortex weakening and its impacts |
publishDate |
2021 |
url |
https://ueaeprints.uea.ac.uk/id/eprint/85511/ https://ueaeprints.uea.ac.uk/id/eprint/85511/1/_15200477_Bulletin_of_the_American_Meteorological_Society_The_2019_Southern_Hemisphere_Stratospheric_Polar_Vortex_Weakening_and_Its_Impacts.pdf https://doi.org/10.1175/BAMS-D-20-0112.1 |
geographic |
Antarctic Austral |
geographic_facet |
Antarctic Austral |
genre |
Antarc* Antarctic polar night |
genre_facet |
Antarc* Antarctic polar night |
op_relation |
https://ueaeprints.uea.ac.uk/id/eprint/85511/1/_15200477_Bulletin_of_the_American_Meteorological_Society_The_2019_Southern_Hemisphere_Stratospheric_Polar_Vortex_Weakening_and_Its_Impacts.pdf Lim, Eun-Pa, Hendon, Harry H., Butler, Amy H., Thompson, David W. J., Lawrence, Zachary D., Scaife, Adam A., Shepherd, Theodore G., Polichtchouk, Inna, Nakamura, Hisashi, Kobayashi, Chiaki, Comer, Ruth, Coy, Lawrence, Dowdy, Andrew, Garreaud, Rene D., Newman, Paul A. and Wang, Guomin (2021) The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts. Bulletin of the American Meteorological Society, 102 (6). E1150–E1171. ISSN 0003-0007 doi:10.1175/BAMS-D-20-0112.1 |
op_doi |
https://doi.org/10.1175/BAMS-D-20-0112.1 |
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Bulletin of the American Meteorological Society |
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102 |
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6 |
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E1150 |
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E1171 |
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1766272267910643712 |