Bachelor and Master Thesis

Please find the 6 potential topics for MSc thesis in the PDF. You are welcome to contact the listed supervisors directly for more information about the projects.

Download project description document HERE.

On the predictability of extreme Arctic ozone depletion events and their impact on tropospheric and surface climate

Arctic ozone can be massively depleted under certain meteorological conditions, such as in spring of 2020, when the Arctic stratosphere was extremely cold and the polar vortex was strong and long- lived. Low levels of Arctic ozone in the stratosphere typically coincide with widespread surface climate anomalies in the Northern Hemisphere, such as warm and dry conditions over Northern Europe and Eurasia. In 2020, record high temperatures during spring over Siberia contributed to the widespread forest fires which burnt over 30 million acres of land. Given the relatively long time- scales of Arctic ozone depletion (~months), a potential linkage between ozone and the large-scale circulation could represent a valuable source of extended predictability. Presently, the predictability of ozone extremes has not been quantified and is the subject of this MSc project. We aim to examine the coupling between ozone and the dynamical state of the stratosphere, by exploring the influence of the polar vortex on ozone. We will evaluate the extended predictability arising from correctly forecasting ozone events, and will assess the implications for tropospheric and surface climate.

Goal and research questions:
The goal of this work will be to quantify the predictability of extreme Arctic ozone anomalies in a set of hindcast model experiments and observations. The research questions are: 1) How predictable are Arctic ozone depletion events? 2) what is the role of the polar vortex in the predictability of such events? 3) do ozone anomalies also affect the predictability of the polar vortex?

Tools and Data:
- ERA5 and MERRA2 reanalysis data will be used to assess the connection between the large-scale circulation and ozone in the observational record.
- The WACCM chemistry-climate model developed at NCAR will be the primary tool to evaluate the predictability of ozone anomalies. Existing model simulations will be used.
- If time allows for it, we could consider running another model (SOCOL) developed at ETH and PMOD. This model would allow us to evaluate the robustness of the WACCM results. The student would run the SOCOL model by her/himself.

Skills and prerequisites:
The Master student should have a strong interest in researching fundamental findings and evaluating them in an applied framework. The student should ideally have experience with plotting (e.g. python) and scientific computing, as well as a background in atmospheric dynamics (e.g. from the classes by Heini Wernli and Daniela Domeisen).

Supervision & Contact:
Gabriel Chiodo (IAC): gabriel.chiodo@env.ethz.ch
Daniela Domeisen (IAC): daniela.domeisen@env.ethz.ch