Dr Lénaïg Brun


        Head and shoulder photo taken on a boat with sea in the background

Physical Oceanography PDRA

I recently obtained a PhD in physical oceanography focused on understanding the role of submarine canyons on slope circulation under the influence of winds, regional currents or tides. I mainly investigated two contrasted cases: the Cassidaigne canyon in the Mediterranean Sea and the Capbreton canyon in the Bay of Biscay. My work involved fieldwork, in-situ data analysis, and the implementation and interpretation of idealized and realistic numerical modelling using CROCO/ROMS.

I am currently working on the POLOMINTS project (POlar Ocean Mixing by INternal TSunamis) that was born out of recent observations of a significant impact of internal tsunamis induced by the calving of a marine-terminating glacier on vertical mixing in polar regions. The study of this process is based on fieldwork, in-situ data analysis and the implementation of a numerical model using MITgcm.

I wish to contribute to the characterization and the understanding of the key mechanisms of internal tsunamigenesis, which is essential in the rapidly changing polar regions in the context of climate change.

Contact details:

Research interests

My areas of research interests are related to physical oceanography and geophysical fluid dynamics specifically coastal, shelf and slope hydrodynamics, geophysical turbulence and mixing, and internal waves generation and propagation in stratified flows.  

I obtained a PhD aimed at understanding the hydrodynamics of submarine canyons and their role in vertical exchanges under the influence of winds, slope currents and tides. My study was centered on two contrasted cases: the Cassidaigne canyon, Northwestern Mediterranean Sea, and the Capbreton canyon, South Bay of Biscay. In the Cassidaigne canyon, my work focused on the generation of transient and stationary deep vertical currents under the influence of surface dynamics. In the Capbreton canyon, I concentrated on analyzing transient processes related to winds and storms, as well as the generation and propagation of internal tides in the canyon due to deep stratification.

I am currently working on the POLOMINTS (POLar Ocean Mixing by Internal TSunamis) project, dedicated to the understanding and characterization of the role of internal tsunamis induced by ice-calving in vertical mixing in polar regions. Understanding this process in fast-evolving polar regions is essential in the context of climate change. My study focuses primarily on the generation, propagation and breaking of internal waves induced by ice-calving from the Sheldon marine-terminating glacier in Ryder Bay, on the Western Antarctic Peninsula. It aims to characterize the dynamics of internal tsunamis generation by identifying the relationship between these processes and calving magnitude and type, and the dependance between their propagation and the bay topography. The analysis also involves investigating their seasonal variability, the internal wave energy and associated dissipation of turbulent kinetic energy, the mixing efficiency, their large-scale relevance and their future evolution.

 

Current projects

POLOMINTS

 

Relevant past projects

Role of submarine canyons on slope circulation: two contrasted cases in the Mediterranean Sea and Bay of Biscay - PhD. Funded by Ifremer. Oct 21 - Nov 24. https://hal.science/tel-05019017v1

Peer-reviewed publications

Brun L., Pairaud I., Silva Jacinto R., Garreau, P. and Dennielou B. (2023) Strong hydrodynamic processes observed in the Mediterranean Cassidaigne submarine canyon. Frontiers in Marine Science, 10, p. 436-453, https://doi.org/10.3389/fmars.2023.1078831 

Brun L., Garreau P., Pairaud I., Silva Jacinto R. (2025) Deep Canyon-Upwellings in the Northwestern Mediterranean Sea in Contrast With Open Oceans. Journal of Geophysical Research: Oceans, 130, e2024JC022008, https://doi.org/10.1029/2024JC022008 

 

Other publications 

Brun L., Silva Jacinto R., Dennielou B., Pairaud I. and Garreau P. (2022), Reworking and transfer to the deep sea of fine-grained turbiditic deposits in the Cassidaigne submarine canyon by internal and regional currents. Virtual Bouma Conference, https://www.youtube.com/watch?v=xs45eL0rUIg

Brun L., Pairaud I., Silva Jacinto R., Garreau P. and Dennielou B. (2023), Hydrodynamic dataset from the UPCAST and CASSISED campaigns in the Cassidaigne canyon (NW Mediterranean Sea). SEANOE, https://doi.org/10.17882/92820, https://www.seanoe.org/data/00816/92820/ 

Brun L., Pairaud I., Silva Jacinto R., Garreau P. and Dennielou B. (2023) Hydrodynamics of the Mediterranean Cassidaigne submarine canyon from observations. EGU General Assembly, Vienna, https://doi.org/10.5194/egusphere-egu23-5490 

Brun L., Garreau P., Pairaud I. and Silva Jacinto R. (2024), Modeling results of an upwelling in an idealized submarine canyon under different stratified conditions. SEANOE, https://doi.org/10.17882/98745, https://www.seanoe.org/data/00876/98745/

Research expeditions

March/April 2023: C-SWOT/WEMSWOT oceanographic cruise, Northwestern Mediterranean Sea, RV Atalante (SHOM). Garreau P. (2023), C-SWOT-2023 cruise, RV Tethys II, https://doi.org/10.17600/18002077

September 2023: PLUMEFLOC oceanographic cruise, Bay of Biscay, RV Pelagia (NIOZ)

 

Public engagement

2022: Organiser of scientific outreach events for Ifremer’s PhD students as a member of the Ifremer’s PhD association, Brest, France.

2022: Participation in an awareness-raising event on climate change for “La Fête de la Science”, Brest, France, Fête de la Science | Université de Bretagne Occidentale

2022: Presentation of a poster on submarine canyons’ hydrodynamics during the scientific outreach event “Science en Theizh 2022”, Brest, France

2022 and 2023: Presentations on research and doctoral studies to students from master and engineering school, Brest, France

2023: Communication manager of the PhD association Dakodoc, aiming at gathering PhD students working on different research projects in Brest during workshops and afterwork events. Organisation of the scientific outreach event “Science en Theizh 2023” aiming at promoting young researchers in Brittany, Brest, France, https://www.scienceentheizh.fr

2023: Presentation of a quiz on submarine canyons’ hydrodynamics during “Science en Theizh 2023”, Brest, France

2023: Training for the scientific outreach competition entitled “My PhD in 180 seconds”, Brest, France

2023: Participation in writing a blog to present and monitor the WEMSWOT 2023 oceanographic campaign: https://www.swot-adac.org/blogs/c-swot-2023/

2024: President of the association Dakodoc. Organisation and supervision of the scientific outreach event “Science en Theizh 2024”

2024: Presentation of a poster entitled “Role of submarine canyons on oceanic circulation” for the UBO (University of Western Brittany) research Day, Brest, France

 

Prizes / awards

Presentation of a poster entitled “Role of submarine canyons on oceanic circulation" for the UBO research Day in 2024, awarded the jury prize by the UBO Foundation, Brest, France, À Brest, trois doctorants récompensés par la fondation UBO | Le Télégramme

 

Media coverage

Le Télégramme, Brest, France

18/01/2024: À Brest, Science en Theizh, pour que comprendre les sciences ne soit pas sorcier | Le Télégramme

24/01/2024: À Brest, trois doctorants récompensés par la fondation UBO | Le Télégramme

17/04/2024: Trois bonnes raisons de se rendre à Science en Theizh, à Brest | Le Télégramme

23/04/2024: À Brest, Science en Theizh a réussi son opération vulgarisation | Le Télégramme

 

Relevant employment history

Since May 2025: PDRA in Physical Oceanography. SAMS

2021-24: PhD in Physical Oceanography. Ifremer

2021: M2 Internship. IMFT

 

Education

2024 PhD 'Role of canyons on slope circulation: two contrasted cases in the Mediterranean Sea and Bay of Biscay'. UBO

2021 Master SOAC. Science of Ocean, Atmosphere and Climate. Université Paul Sabatier

2021 Engineering degree.  Mechanical and Hydraulic Engineering. INP ENSEEIHT