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Schlagwörter:
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Zusammenfassung:
Despite offsetting global mean surface temperature, various studies demonstrated that Stratospheric Aerosol Injection (SAI) could influence the recovery of stratospheric ozone and have important impacts on stratospheric and tropospheric circulation, thereby potentially playing an important role in modulating regional and seasonal climate variability. However, so far most of the assessments of such an approach have come from climate model simulations in which SO2 is injected only in a single location or a set of locations. Here we use CESM2-WACCM6 SAI simulations under a comprehensive set of SAI strategies achieving the same global mean surface temperature with different locations and/or timing of injections: an equatorial injection, an annual injection of equal amounts of SO2 at 15N and 15S, an annual injection of equal amounts of SO2 at 30N and 30S, and a polar strategy injecting SO2 at 60N and 60S only in spring in each hemisphere. We demonstrate that despite achieving the same global mean surface temperature, the different strategies result in contrastingly different impacts on stratospheric temperatures and circulation, thereby leading to different impacts on Northern Hemispheric polar vortex and, thus, winter mid- and high latitude surface climate, as well as leading to important differences in the future evolution of stratospheric ozone throughout the globe. Overall, the results contribute to an increased understanding of the underlying physical processes as well as lay ground for identifying an optimal SAI strategy that could form a basis of a future multi-model assessment.
