Which Sudden Stratospheric Warming Events Are Most Predictable?

Dvir Chwat, Chaim I. Garfinkel*, Wen Chen, Jian Rao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The predictability of Northern Hemisphere sudden stratospheric warming (SSW) events is considered in 10 subseasonal to seasonal (S2S) forecast models for 16 major SSWs that have occurred since 1998, a larger sample size than has been considered by previous works. The four factors that most succinctly distinguish those SSWs with above average predictability are a preconditioned vortex prior to the SSW, an active Madden-Julian Oscillation with enhanced convection in the West Pacific, the Quasi-Biennial Oscillation phase with easterlies in the lower stratosphere, and the vortex morphology (displacement more predictable). Two of these factors appear to not have been considered in previous works focusing on a large sample of events. Most of these effects are not statistically significant at the 95% level due to the still relatively small sample size, though all would exceed a 90% criteria at least marginally. Combined, however, they account for 40% of the inter-event spread in SSW predictability, thus indicating that SSWs with favorable precursors are significantly more predictable.

Original languageAmerican English
Article numbere2022JD037521
JournalJournal of Geophysical Research: Atmospheres
Volume127
Issue number18
DOIs
StatePublished - 27 Sep 2022

Bibliographical note

Publisher Copyright:
© 2022. The Authors.

Keywords

  • ENSO
  • MJO
  • subseasonal predictability
  • sudden warmings

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