Yueng-Djern Lenn

Professor Yueng-Djern Lenn is a distinguished polar physical oceanographer at Bangor University's School of Ocean Sciences, where they hold the position of Professor. With a research career spanning nearly two decades, Professor Lenn has established themselves as a leading expert in polar ocean dynamics, particularly focusing on the physical processes that drive ocean overturning circulation in both the Arctic and Southern Oceans.

Professor Lenn earned their MA in Experimental and Theoretical Physics from Cambridge University (1997), followed by an MSc in Medical Radiation Physics from University College London (1998), and completed their PhD in Observations of Antarctic Circumpolar Current Dynamics and Small-scale variability near the Antarctic peninsula from Scripps Institution of Oceanography, La Jolla (2006). Their academic journey has progressed through positions from Postdoctoral Research Fellow to Lecturer, Reader in Physical Oceanography, and ultimately to Professor at Bangor University.

Professor Lenn's research focuses on understanding the physical processes integral to ocean overturning that impact climate in polar regions. Their work examines Drake Passage eddy heat and momentum fluxes, the surface Ekman layer that constitutes the upper limb of the overturning circulation, and diapycnal mixing driving water mass transformation in the thermocline at the Antarctic continental slope. In the Arctic, their research centers on water mass transformations occurring in continental shelf seas and along the Arctic continental slope that link the Arctic to global overturning circulation. They investigate the role of different mixing mechanisms—including double diffusion and turbulent mixing driven by tides or winds—in fluxing heat and other properties from warm Atlantic Water into overlying Arctic halocline and mixed layers.

Analysis of Professor Lenn's recent publications reveals a strong focus on Arctic Ocean dynamics, particularly examining how changing ocean conditions affect sea ice, water mass transformation, and climate feedbacks. Their work spans observational studies, modeling approaches, and theoretical frameworks, with increasing emphasis on the impacts of declining sea ice cover and the phenomenon of Arctic Atlantification. The research demonstrates sophisticated methodologies for measuring ocean turbulence and mixing processes, contributing significantly to our understanding of polar climate systems.

• John F. Nye Lecturer (December 2022)
• John F Nye Lecturer (September 2022)
• Elected Fellow of the Learned Society of Wales (May 2024)

Professor Lenn actively supervises PhD students, including Will Stewart (Bangor University, from September 2022), and has previously mentored Ben Barton (Universite de Bretagne Occidentale) and Jess Mead Silvester (Bangor University). Their research is supported by significant grants including DIMSUM (Drivers and impacts of North Atlantic heat and freshwater fluxes unsettling modern-day climate, 2023-2026), QUICCHE (Quantifying inter-ocean fluxes in the Cape Cauldron of high EKE, 2022-2027), and ArctiCONNECT (2020-2025). They also serve as the schools liaison for the School of Ocean Sciences, coordinating school visits and STEM outreach activities in partnership with organizations like STEMCymru.

Professor Lenn leads and contributes to multiple research teams focused on polar oceanography, including the ATOMIX working group (Analysing ocean turbulence observations to quantify mixing) which they chaired from 2020-2023. They are an active participant in international research collaborations, serving on editorial boards including the Journal of Physical Oceanography, and regularly contribute to major scientific conferences and public engagement initiatives including BBC documentaries and media appearances.