Impact of sudden stratospheric warmings on the stratosphere-to-troposphere transport of ozone

• Published in: Geophysical Research Letters
• Main Authors: Lee, Jaewon, Butler, Amy H., Albers, John R., Wu, Yutian, Lee, Simon H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2025
• Subjects: Sudden stratospheric warming; Stratosphere-troposphere coupling; Chemical transport; Ozone; Subseasonal-to-seasonal; ENSO; Arctic
• Online Access: https://research-portal.st-andrews.ac.uk/en/publications/354fa2d5-c992-4001-8801-8cd7b530eef1; https://doi.org/10.1029/2024GL112588; https://research-repository.st-andrews.ac.uk/bitstream/10023/31312/1/Lee_2025_GRL_Impact-stratospheric-warmings-transport-ozone_CC.pdf

Sudden stratospheric warmings (SSWs) can significantly impact tropospheric weather systems. Previous studies suggest that SSWs may also influence stratosphere-to-troposphere transport (STT), but their spatial and temporal distribution and mechanisms are not fully understood. The complex relationships between SSWs and the El Niño-Southern Oscillation (ENSO) have also made it difficult to isolate the effects of SSWs on STT. From an idealized ENSO simulation with the WACCM4 model using a stratospheric origin ozone tracer, we investigate the effect of SSWs on the STT of ozone under different ENSO phases. We find a significant increase in lower tropospheric ozone from the SSW onset up to 3 months later over the Arctic, North America, and Europe, regardless of the ENSO phase. This study highlights the significant influence of SSWs on STT on a subseasonal scale. Our results also emphasize the need to consider SSWs when addressing the ENSO impact on STT.