Influences of Antarctic Ozone Depletion on Southern Ocean Aerosols

The Southern Ocean is often identified as a pristine aerosol environment, being distant from anthropogenic sources. We investigate anomalies in aerosol loading over the Southern Ocean due to stratospheric ozone depletion in historical simulations performed for the sixth Coupled Model Intercomparison Project. We explore direct influences of ozone depletion on aerosols via enhanced ultraviolet-induced production of oceanic dimethyl sulfide (DMS), and indirect influences via changes in the Southern Hemisphere westerly jet, which impacts wind-driven aerosol fluxes. We identify wind as the key driver of change for austral summertime aerosol, leading to increases in aerosol optical depth of up to 24% compared with the pre-ozone hole era. In contrast to previous studies, direct impacts on aerosol from ozone depletion and enhanced ultraviolet fluxes are less obvious. Our results show that the Southern Ocean summertime aerosol environment cannot be considered to be representative of pre-ozone hole conditions because stratospheric ozone depletion has indirectly increased marine aerosol fluxes.

Automated summary

In this study, anomalies in aerosol loading over the Southern Ocean due to stratospheric ozone depletion were investigated using historical simulations. The results show that the aerosol environment over the Southern Ocean in summertime is no longer representative of pre-ozone hole conditions due to increased marine aerosol fluxes indirectly influenced by stratospheric ozone depletion.