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 language | American English |
|---|---|
| Article number | e2022JD037521 |
| Journal | Journal of Geophysical Research: Atmospheres |
| Volume | 127 |
| Issue number | 18 |
| DOIs | |
| State | Published - 27 Sep 2022 |
Bibliographical note
Funding Information:DC, CIG, and WC are supported by the ISF-NSFC joint research program (ISF Grant No. 3259/19 and National Natural Science Foundation of China Grant No. 41961144025). CIG and DC were also supported by a European Research Council starting grant under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 677756). We thank the two reviewers for their constructive comments on an earlier version of this paper. JR was supported by the National Natural Science Foundation of China (Grant No. 42175069). This work is based on S2S data. S2S is a joint initiative of the World Weather Research Programme (WWRP) and the World Climate Research Programme (WCRP).
Funding Information:
DC, CIG, and WC are supported by the ISF‐NSFC joint research program (ISF Grant No. 3259/19 and National Natural Science Foundation of China Grant No. 41961144025). CIG and DC were also supported by a European Research Council starting grant under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 677756). We thank the two reviewers for their constructive comments on an earlier version of this paper. JR was supported by the National Natural Science Foundation of China (Grant No. 42175069). This work is based on S2S data. S2S is a joint initiative of the World Weather Research Programme (WWRP) and the World Climate Research Programme (WCRP).
Publisher Copyright:
© 2022. The Authors.
Keywords
- ENSO
- MJO
- subseasonal predictability
- sudden warmings