,,- Utrecht University, IMAU, Netherlands (m.g.l.denooij@students.uu.nl)
Extratropical cyclones (ETCs) are associated with extreme winds, heavy rainfall, and storm surges, but also provide beneficial precipitation. Their trajectories and intensity are expected to shift under global warming, and these changes may not be fully restored by Stratospheric Aerosol Injection (SAI).
We studied the effect of SAI on extratropical cyclone trajectories, properties, and analysed their risk potential using a set of 3 CESM1 simulations, one at constant year-2000 conditions (“present-day”), a high-emissions scenario with strongly increasing CO₂ concentrations (“RCP8.5”), and one in which CO₂ follows RCP8.5, but global mean surface temperature is cooled back to year-2000 conditions from 2050 onwards by means of SAI (“SAI”).
To save computation time, we use the atmosphere component CAM (rather than the several times more expensive WACCM). CAM does not model the evolution of stratospheric aerosol, hence we force the model with stratospheric aerosol fields obtained from CESM-WACCM simulations (Tilmes et al, 2018). The aerosol concentrations are scaled using a feedback procedure in order to achieve the temperature target (de Jong et al, 2025).
We find that the number of extratropical cyclone tracks decreases under RCP8.5, especially in the Southern Hemisphere, while the precipitation per cyclone increases. SAI roughly reverts these changes. The wind and pressure distributions are not strongly affected by either SAI or RCP8.5. However, the location of the North Atlantic and North Pacific storm tracks is found to shift northwards and southwards, respectively, under SAI.
Additionally, we find that under RCP8.5, ETC-related extreme precipitation events increase. Under SAI, these events decrease below present-day levels, suggesting an overcompensation. ETC-related extreme wind events decrease under RCP8.5 and decline further under SAI.
References:
Tilmes et al., 2018: https://journals.ametsoc.org/view/journals/bams/99/11/bams-d-17-0267.1.xml
De Jong et al., 2025: https://gmd.copernicus.org/articles/18/8679/2025/
How to cite: de Nooij, M., de Jong, J., Wieners, C., and Baatsen, M.: Impact of SAI on extra-tropical cyclones in a high-resolution simulation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13659, https://doi.org/10.5194/egusphere-egu26-13659, 2026.
