Does the coupling of the semiannual oscillation with the quasi-biennial oscillation provide predictability of Antarctic sudden stratospheric warmings?

Nordström, Viktoria J.; Seppälä, Annika

doi:https://doi.org/10.5194/acp-21-12835-2021

Articles | Volume 21, issue 17

https://doi.org/10.5194/acp-21-12835-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-21-12835-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 21, issue 17

Research article

|

31 Aug 2021

Research article |

| 31 Aug 2021

Does the coupling of the semiannual oscillation with the quasi-biennial oscillation provide predictability of Antarctic sudden stratospheric warmings?

Viktoria J. Nordström and Annika Seppälä

Supplement

https://doi.org/10.5194/acp-21-12835-2021-supplement

Data sets

MERRA-2 inst6_3d_ana_Np: 3d,6-Hourly,Instantaneous,Pressure-Level,Analysis,Analyzed Meteorological Fields V5.12.4 Global Modeling and Assimilation Office (GMAO) https://doi.org/10.5067/A7S6XP56VZWS

Multivariate ENSO Index Version 2 (MEI.v2) NOAA https://psl.noaa.gov/enso/mei/

Madden-Julian oscillation index (MJO) NOAA https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/whindex.shtml

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Short summary

The winter winds over Antarctica form a stable vortex. However, in 2019 the vortex was disrupted and the temperature in the polar stratosphere rose by 50°C. This event, called a sudden stratospheric warming, is a rare event in the Southern Hemisphere, with the only known major event having taken place in 2002. The 2019 event helps us unravel its causes, which are largely unknown. We have discovered a unique behaviour of the equatorial winds in 2002 and 2019 that may signal an impending SH SSW.