Potential non-linearities in the high latitude circulation and ozone
response to Stratospheric Aerosol Injection
Abstract
The impacts of Stratospheric Aerosol Injection (SAI) on the atmosphere
and surface climate depend on when and where the sulfate aerosol
precursors are injected, as well as on how much surface cooling is to be
achieved. We use a set of CESM2(WACCM6) SAI simulations achieving three
different levels of global mean surface cooling and demonstrate that
unlike some direct surface climate impacts driven by the reflection of
solar radiation by sulfate aerosols, the SAI-induced changes in the high
latitude circulation and ozone are more complex and could be non-linear.
This manifests in our simulations by disproportionally larger Antarctic
springtime ozone loss, significantly larger intra-ensemble spread of the
Arctic stratospheric jet and ozone responses, and non-linear impacts on
the extratropical modes of surface climate variability under the
strongest-cooling SAI scenario compared to the weakest one. These
potential non-linearities may add to uncertainties in projections of
regional surface impacts under SAI.