Congratulations!Marc Lennartz successfully presented his MSc thesis

28 January 2025

Photo: privat

Marc Lennartz’s thesis, “Exploring Hourly Rainfall Extremes in a Changing Climate: A
Comparative Analysis of sMEV and GEV Distributions Using COSMO-CLM Simulations over
Germany” was supervised by Dr. Benjamin Poschlod (PostDoc for Sustainability and Climate
Risks, Universität Hamburg) and Prof. Dr. Jürgen Böhner (Professor of Physical Geography,
Universität Hamburg).

The objective of this study is to test the performance of the sMEV and GEV for hourly
precipitation using a high-resolution regional climate model. The global climate model MIROC5
is employed to drive the regional climate model COSMO over the greater Germany area for the
past, near future and distant future. It computes at a high spatial (~3 km) and temporal (hourly)
resolution, allowing it to explicitly resolve deep convection. No comparable time series from a
convection-permitting-model has previously been analyzed using the sMEV distribution.

The results show that the sMEV performs much better than the GEV in terms of the uncertainty
for almost all return periods regardless of the observational years available. In addition, there is
a north-south gradient in the return level difference, the uncertainty difference and the
adequacy of the threshold chosen for the sMEV. Investigating non-stationary versions of the
sMEV and GEV shows that the non-stationary sMEV is more suitable to describing the change in
return levels. However, both versions of the non-stationary distributions that are analyzed lack
complexity and should not be used in predicting return levels for higher temperatures.

Following the successful completion of the MICSS program Marc will pursue a PhD position at
the GFZ in Potsdam. He aims to understand and prepare for High-Impact and Low-Probability
flood events.