SHOTGAP · Southern Hemispheric Ozone in the Troposphere in the Context of Global Warming and Air Pollution

Tropospheric ozone is 1. the third most important anthropogenic greenhouse gas, contributing to global warming, and 2. an air pollutant, responsible for more than 1 million premature deaths annually. At the same time, ozone is a complex trace gas to study as it is not emitted directly but formed via non-linear photochemical reactions. Recent literature has shown that surface ozone levels are increasing in the remote Southern Hemisphere (SH), but the reason for these enhancements is currently not understood. The SH is vastly understudied due to the preponderance of Northern Hemispheric researchers and the lack of local measurements despite facing major challenges, including growing population and industrialization. The remote SH currently resembles pre-industrial conditions the most, but is increasingly impacted by anthropogenic influences, as indicated by observations of increasing ozone - with implications for the global climate. In the project SHOTGAP, I will investigate photochemical processes that lead to SH ozone formation and changes thereof over time, based on a combination of in-situ measurements from ground and aircraft, satellite observations and global models. I will (i) characterize current SH photochemistry, (ii) identify all changes in potential ozone drivers, including anthropogenic and natural precursors, meteorological parameters and transport processes over the last two decades, (iii) link these to changes in ozone and (iv) investigate future scenarios. The overall objective of SHOTGAP is to understand through which mechanisms SH ozone levels are increasing and how SH ozone could evolve in the future based on different socio-economic pathways. The results will act as a guidepost for policy makers to steer future emissions in the SH with the goal of minimizing ozone and its implications for climate and human health. SHOTGAP will enhance my scientific and methodological knowledge and support my goal to become an independent researcher.