Successful doctoral thesis provides new insights into the dynamics of the polar mesosphere

Kühlungsborn, 06.102.2026 – On 30 January 2026, our doctoral student Jennifer Hartisch successfully defended her thesis at the University of Rostock. In her dissertation, she investigated previously underestimated dynamic structures in the polar mesosphere and lower thermosphere (MLT), a poorly accessible transition region between the atmosphere and space.

The work was based on high-resolution radar observations from the Middle Atmosphere Alomar Radar System (MAARSY) in northern Norway. Using polar mesospheric summer echoes (PMSE) as tracers, she systematically evaluated data from 2015 to 2021 and identified over 700 so-called varicose structures. These are characterised by simultaneous upward and downward movements with extreme vertical velocities, occur during the main season with a monthly probability of up to 2.5% and often lead to a significant broadening of the PMSE layer.

The work shows that varicose structures are a common and so far underestimated phenomenon in the polar mesosphere. Due to their strong dynamics and coupling to small-scale processes, they play an important role in understanding the MLT and should be given greater consideration in numerical atmospheric models in the future.

We cordially congratulate Dr Hartisch on this success!