PhD Defence – Waves and tropical cyclones

On 27 April 2026, Clément Pouplin will defend his PhD on the characterisation of wave fields induced by tropical cyclones. The event will take place at 9.00 am at the Institut Universitaire Européen de la Mer in Plouzané, France.

His work, supervised by Jean-François Filipot (France Energies Marines) and Alexis Mouche and Bertrand Chapron (Ifremer), was carried out as part of the OROWSHI R&D project (2022–2025), which focused on estimating statistics for extreme winds and waves affecting offshore wind turbines exposed to tropical cyclones.

Taking part online

Summary

Tropical cyclone wind fields generate complex sea states. Wave observations within tropical cyclones are scarce, and data quality is often degraded as measurement methods reach their limits in such extreme environments. Eulerian spectral models require a high resolution to accurately capture the fine-scale structure of tropical cyclone wave fields, coming at a high computational cost.

The ability of a Lagrangian framework to model TC-induced sea states is investigated. Wave groups are represented by Lagrangian particles, whose properties are governed by a system of five coupled differential equations. A methodology is proposed to equivalently reduce wave spectral information from both Eulerian and Lagrangian frameworks, exploiting specific shapes observed in tropical cyclone-induced wave spectra. This reduction enables to represent sea states in a consistent manner across drastically different observation techniques, and to describe the spatial distribution of their spectral characteristics during complete tropical cyclone life cycles. The potential of swell measurements to characterize the spatial variability of the sea state from outside the tropical cyclone core is also analyzed.

Both methodologies are combined to evaluate the performance of the Lagrangian framework to model the sea states inside tropical cyclones.

Composition of the jury

• Jean-François FILIPOT, Scientific Director, France Energies Marines – Thesis Director
• Alexander BABANIN, Professor, University of Melbourne – Rapporteur
• Xiaoli Guo LARSEN, Professor, Technical University of Denmark (DTU) – Rapporteur
• Xavier CARTON, Professor, Université de Bretagne Occidentale – Chairman
• Marie-Noëlle BOUIN, Researcher, Centre National de Recherches Météorologiques – Examiner
• France FLOC’H, Lecturer-Researcher, Université de Bretagne Occidentale – Examiner
• Danièle HAUSER, Research Director, Laboratoire Atmosphères, Observations Spatiales – Examiner
• Ludivine ORUBA, University Lecturer, Sorbonne Université – Examiner

Photo credit: France Energies Marines, WikiImages / Pixabay