Sensitivity of Stratospheric Ozone to Volcanic Eruptions: Modelled Dependencies on Latitude, Season, and Halogen Content of the Eruption

The ozone layer in the stratosphere is essential in protecting life on Earth from harmful UV irradiation, and even small changes in ozone layer thickness can cause significant damage to human health and agriculture. Knowing the methods and causes for ozone depletion is therefore critical. As the atmospheric halogen loading moves towards pre-industrial levels in the future, the largest perturbation to the ozone layer could be caused by volcanic eruptions. Large explosive volcanic eruptions have the potential to alter the spatiotemporal profiles of the ozone column through changes in trace gas composition and aerosol loading of the stratosphere. Along with sulphur compounds, volcanic eruptions can inject halogens into the stratosphere, potentially leading to sudden and dramatic ozone losses on a hemispheric scale.

We present a large-ensemble 3-D chemistry-climate-aerosol model evaluation of the response of stratospheric ozone to volcanic perturbation of sulfate aerosol as a consequence of latitude, season, and halogen content of eruption in a chemistry-climate state representative of the year 2025 using the SOCOL-AERv2 model (SOCOL = modeling tools for studies of SOlar Climate Ozone Links, AER = 2D aerosol model). Six representative volcanoes were selected as proxies to investigate the latitudinal dependence of the impact of a large, explosive volcanic eruption on stratospheric ozone chosen for informational and not prognostic purposes. We investigate the impact of the latitude, seasonality and halogen content for eruptions modeled as occurring in January and July 2025. Differences in the results for hemispherical and global impacts are discussed, comparing the impact of each eruption scenario on the aerosol loading of the atmosphere and stratospheric ozone layer.