Report - Research Stay in Toulouse, France by Henning Franke

My name is Henning Franke, and I am a Postdoctoral Researcher in subproject L4, „Multiscale Ocean-Atmosphere Coupling“, at the Max Planck Institute for Meteorology (MPI-M). My scientific work focuses on better understanding the role of small-scale heterogeneity of the sea surface temperature in driving convective precipitation over tropical oceans in km-scale global climate simulations. For this task, it is important to reliably identify deep convective systems - commonly referred to as mesoscale convective systems (MCS) -  in the simulations, which is usually done by MCS tracking algorithms. One of the world’s most sophisticated MCS tracking algorithm is the TOOCAN algorithm, which is developed by Dr. Thomas Fiolleau and Dr. Rémy Roca. In order to learn about the application of TOOCAN on my own climate simulations with the km-scale model ICON, I visited Thomas and Rémy at their lab in Toulouse at the end of January 2026.

The week started with getting to know the members of the research group led by Rémy and by presenting my ongoing and planned research in their weekly group meeting. Afterwards, I received a comprehensive overview of TOOCAN from Thomas, which proved to be very helpful to understand how TOOCAN actually works and what distinguishes it from other MCS tracking algorithms. With the extensive support of Thomas, I was able to get TOOCAN running on my ICON simulations within just two days. Therefore, there was even some time for an initial analysis of the TOOCAN output. I discussed these results with Rémy in detail, and given Rémy’s extensive expertise on deep convection, these discussions were really helpful for me and stimulated some new ideas for my research that I plan to test in the future.

Additionally, I liked experiencing a different research culture in another institute and working group, and I was impressed by the level of engagement and scientific discussions within the working group. The working group made me feel welcome immediately, which was not only due to the bar night and the joint lunches, which I really enjoyed.

In addition to the academic experience, my time in Toulouse was very pleasant and flew by far too quickly. Toulouse itself is a beautiful and lively city, and I particularly liked its historic old town with its many nice restaurants and cafés. Those offered plenty of possibilities to enjoy the great French cuisine, which I miss a lot. I also miss my runs along the Canal du Midi, a historic waterway that stretches from Toulouse to the Mediterranean Sea, winding through the city.

I would like to express my gratitude to Rémy and Thomas for organizing a very pleasant and interesting stay in Toulouse. My special thanks go to Thomas for his extensive support with TOOCAN - I don’t think that I would have been able to set up TOOCAN that quickly without the possibility to ask him countless questions whenever I needed to. Overall, my stay in Toulouse was very valuable, and in my opinion it would have been very hard to get TOOCAN running if I would have stayed in Hamburg. Therefore, I would like to also thank the TRR181 for providing the funding for this research trip.