[ESAC Seminar] Selena Zhang

“Investigating Record-high Ozone in the Austral Mid-latitude Tropopause Region”

In 2019, the Southern Hemisphere experienced two extreme events: the Australian Black Summer fires and a rare sudden stratospheric warming (SSW). Following these events, record-high ozone in the southern mid-latitude lowermost stratosphere/upper troposphere was observed by satellites. Ozone is an important greenhouse gas in these altitudes: 10 to 15 kilometers above the surface. In this study, we use numerical model simulations and satellite data to investigate the impacts of these events on ozone. We find that most of the ozone enhancement (around 80%) can be explained by transport of polar air associated with the SSW, with a smaller contribution from chemical impacts of the wildfires (around 20%). It is important to note that the intensity of the 2019-2020 Australian wildfire season has previously been attributed to the 2019 SSW, which exacerbated hot and dry conditions over Australia. Thus, we conclude that the SSW is largely responsible for both dynamical and chemical contributions to these high ozone levels.

ESAC Student Seminar Series —

A forum for students and postdocs to share recent research, hone presentation skills, and build community among peers, sponsored by the EAPS Student Advisory Committee. Open to current EAPS graduate and undergraduate students and postdocs. Typically hosted on Thursdays during the semester, including pizza lunch.

Contact: esac.officers@gmail.com