PhD project
Title: The quasi-biennial oscillation in a warming climate
Supervision: Marco Giorgetta, Ulrike Niemeier, Bjorn Stevens

In my PhD project I investigate how and why the quasi-biennial oscillation (QBO) of the zonal wind in the tropical stratosphere may change in a warming climate. To tackle this question I use high resolution simulations with the global circulation model ICON, which explicitly resolve convection as well as gravity waves. This enables a direct simulation of the QBO without the need for relevant parametrizations, which are needed in coarser resolution models and which are accompanied by overwhelming uncertainties, preventing a conclusive answer about the QBO characteristics in a warming climate so far.

Further interests
1) Dynamics of the QBO and its response to external forcings (e.g. volcanic eruptions or geoengineering)
2) General circulation in the stratosphere and its response to external forcings (e.g. volcanic eruptions or geoengineering)
3) Dynamic coupling between the stratosphere and the troposphere
 

M.Sc. Meteorology, University of Hamburg (2017 - 2020)
Master's Thesis: Stratospheric Injection of Sulfur - Injection of H₂SO₄ Compared to Injection of SO₂
Stay abroad: The University Centre in Svalbard (Longyearbyen, Norway), 2018

B.Sc. Meteorology, University of Hamburg (2014 - 2018)
Bachelor's Thesis: Cloud Correlations in Tropical Convection
Stay abroad: University of Oklahoma (Norman, USA), 2016
 

H. Franke, U. Niemeier, D. Visioni (2021). Differences in the quasi-biennial oscillation response to stratospheric aerosol modification depending on injection strategy and species, Atmos. Chem. Phys., https://doi.org/10.5194/acp-21-8615-2021

D. K. Weisenstein, D. Visioni, H. Franke, U. Niemeier, S. Vattioni, G. Chiodo, T. Peter, and D. W. Keith (2021). A Model Intercomparison of Stratospheric Solar Geoengineering by Accumulation-Mode Sulfate Aerosols, Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2021-569, in review.

Presentations at conferences:
H. Franke and U. Niemeier: Differences in the QBO response to artificial stratospheric aerosol injections depending on injection strategy and species, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8173, https://doi.org/10.5194/egusphere-egu21-8173, 2021.

I. Quaglia, C. Brühl, S. Dhomse, H. Franke, A. Laakso, G. Mann, M. Mills, U. Niemeier, G. Pitari, T. Sukhodolov, C. Timmreck, P. Tuccella, and D. Visioni: Interactive Stratospheric Aerosol models response to different sulfur injection amount and altitude distribution during volcanic eruption, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13387, https://doi.org/10.5194/egusphere-egu21-13387, 2021.

Participitation in research cruise SO284
Details: R/V Sonne, 2021/06/27 - 2021/08/17, Emden - Tropical Atlantic - Emden
Duties: Launching of radiosondes in the Intertropical Convergence Zone (ITCZ)