An intermediate-complexity moist general circulation model is used to investigate the factors controlling the magnitude of the surface impact from Southern Hemisphere springtime ozone depletion. In contrast to previous idealized studies, a model with full radiation is used; furthermore, the model can be run with a varied representation of the surface, from a zonally uniform aquaplanet to a configuration with realistic stationary waves. The model captures the observed summertime positive Southern Annular Mode response to stratospheric ozone depletion. While synoptic waves dominate the long-term poleward jet shift, the initial response includes changes in planetary waves that simultaneously moderate the polar cap cooling (i.e., a negative feedback) and also constitute nearly one-half of the initial momentum flux response that shifts the jet poleward. The net effect is that stationary waves weaken the circulation response to ozone depletion in both the stratosphere and troposphere and also delay the response until summer rather than spring when ozone depletion peaks. It is also found that Antarctic surface cooling in response to ozone depletion helps to strengthen the poleward shift; however, shortwave surface effects of ozone are not critical. These surface temperature and stationary wave feedbacks are strong enough to overwhelm the previously recognized jet latitude/persistence feedback, potentially explaining why some recent comprehensive models do not exhibit a clear relationship between jet latitude/persistence and the magnitude of the response to ozone. The jet response is shown to be linear with respect to the magnitude of the imposed stratospheric perturbation, demonstrating the usefulness of interannual variability in ozone depletion for subseasonal forecasting.
Bibliographical noteFunding Information:
Acknowledgments. Authors Garfinkel, White, and Gerber acknowledge the support of a European Research Council starting grant under the European Union Horizon 2020 research and innovation program (grant agreement 677756). Garfinkel is also supported by Israel Science Foundation Grant 1727/21. Gerber acknowledges additional support from the U.S. NSF through Grant AGS 1852727. Author Jucker acknowledges support from the Australian Research Council (ARC) Centre of Excellence for Climate Extremes (CE170100023) and ARC Grant FL 150100035. Author Son was supported by the National Research Foundation of Korea (NRF) grant funded by the South Korean government (Ministry of Science and ICT 2017R1E1A1A01074889). We thank the reviewers for their helpful comments on earlier drafts of this paper.
© 2022 American Meteorological Society.
- Antarctic Oscillation
- Shortwave radiation
- Stationary waves
- Stratosphere-troposphere coupling