Report - Research Stay in Lyon by Mohamed Mossad

Text: Mohamed Mossad

Exploring Atmospheric Dynamics

From the 1st of October and until the 14th, I had the opportunity to embark on a short research stay in Lyon, France, funded by the project TRR181 at École Centrale de Lyon. This period was not just a chance to collaborate and learn but also a stepping stone in my understanding of atmospheric dynamics, particularly regarding gravity wave (GW) spectra.

My time in Lyon was spent working alongside Raffaele Marino (scientist at CNRS, France) and the team at the Laboratory Mechanical Des Fluides Et D'acoustique (LMFA). The environment at LMFA was not only academically stimulating but also warmly welcoming, fostering both professional growth and personal connections.

One of the most enlightening aspects of this visit was the shift in my perspective on the processes which contribute to the canonical GW spectra. Discussions about turbulence and the scaling of gravity wave spectra opened my eyes to the broader physics underlying these phenomena. It was a transition from focusing merely on the slope of gravity wave spectra to understanding the vast, open-ended field of their scaling.

A highlight of my stay was exploring the relationship between the Froude number and statistics (kurtosis) of velocity and temperature fields. Although time constraints didn’t allow for its application on lidar data, the concepts presented were inspiring and thought-provoking.

Our work concentrated on validation of spectra from direct numerical simulations (DNS) against lidar data, scrutinizing how different wind regimes affect GW spectra. This involved a detailed comparison of integrated kinetic energy/scalar spectra with lidar data.

Leaving Lyon, I am armed with an array of studies and topics to delve into, especially regarding the comparison with DNS regimes. These studies are pivotal in enhancing our interpretation of GW data from lidar measurements. I am optimistic about the continuation of this collaboration in the future and the potential for significant findings.

Beyond the academic realm, Lyon itself proved to be a delightful experience. The city's transportation system was notably efficient which made commuting a breeze. The streets of Lyon are filled with friendly faces, many of them young students, also the 2023 Rugby World Cup was taking place there which added a lively and diverse vibe to the city. École Centrale de Lyon, nestled in this vibrant environment, struck me as an exceptional place for study and research, providing many chances to do sports as well.

I extend my deepest gratitude to the entire team at LMFA for their hospitality and support. Special thanks go to Rafaello Foldes and Fabio Feraco (IAP) for their invaluable help in answering my questions and assistance with data provision.

My research stay in Lyon was not only productive but also immensely rewarding. It has broadened my understanding and has surely impacted my approach to atmospheric science. I am grateful for this experience and hopeful that my contributions, though a fraction, have added value to our collective research endeavors.