We mostly study fluid dynamical processes in the context of the ocean, principally via computational methods. While the motivating context is on global/regional settings and we touch on climate/biogeochemistry/ecology/modelling applications, the focus is on the physical processes. On this site you can find information about our research projects (which also includes some non-ocean things we do), and the members making it happen.

Our research activities are funded by the RGC. We are also partly affiliated with the CORE program. Those interested in joining the group as a student/staff are generally welcome to contact Julian Mak, no guarantees we have openings though (we are essentially fully committed in terms of time and money at this present time). If you are looking for short projects (e.g. UG or MSc students, doesn't have to be within ocean science department itself), then please see blurb at this link.


Bobo has been awarded the Anita Conti Fellowship scheme managed by the Consulate General of France in Hong Kong and Macau. She will be spending September to December 2024 as a visitor at the LOCEAN group at Paris Sorbonne, working on something to do with modelling of marine biogeochemical cycles.

Julian is part of a group on a successful HKRGC CRF application (C5013-23GF, "Multi-sensor monitoring, geophysical interpretation and prediction of sea level rise in Hong Kong", led by Prof. Jianli Chen at PolyU). Watch this space for job advertisements in due course.

Welcome to Jonathan and Virryna, who are starting with the group from Spring 2024. Jonathan is funded through the Hong Kong PhD Fellowship Scheme (HKPFS), to work on coastal modelling and associated inverse/optimisation problems. Virryna is joining as a post-doc to work on some Arctic eddy dynamics, and some work in relation to the modelling of the South China Sea.

Fei Er has been awarded the Anita Conti Fellowship scheme managed by the Consulate General of France in Hong Kong and Macau. She will be spending September to December 2023 as a visitor at the MEOM group at IGE Grenoble, working on something machine learning related.

Recent misc. outputs

Animation of the some Lagrangian particles (labelled as rubber ducks) being dispersed in a time-periodic double gyre flow. Driver code by Dan Bartley.

Combined physical and biogeochemical assessment of mesoscale eddy parameterisations in ocean models: eddy induced advection at eddy-permitting resolutions

X. Ruan, D. Couespel, M. Lévy, J. Li, J. Mak & Y. Wang (2024) [doi]
Ocean Modell., 190, 102396

On the choice of training data for machine learning of geostrophic mesoscale turbulence

F. E. Yan, J. Mak & Y. Wang (2024) [doi]
J. Adv. Model. Earth. Syst., 16(2), e2023MS003915

Parameterizing eddy buoyancy fluxes across prograde shelf/slope fronts using a slope-aware GEOMETRIC closure

H. Wei, Y. Wang & J. Mak (2024) [doi]
J. Phys. Oceanogr., 54(2), 359-377

Scale-awareness in an eddy energy constrained mesoscale eddy parameterization

J. Mak, J. R. Maddison, D. P. Marshall, X. Ruan, Y. Wang & L. Yeow (2023) [doi]
J. Adv. Model. Earth. Syst., 15(12), e2023MS003886

Global estimation of the eddy kinetic energy dissipation from a diagnostic energy balance

R. Torres, R. Waldman, J. Mak & R. Séférian (2023) [doi]
Geophys. Res. Lett., 50(20), e2023GL104688

Combined physical and biogeochemical assessment of mesoscale eddy parameterisations in ocean models: eddy induced advection at non-eddying resolutions

X. Ruan, D. Couespel, M. Lévy, J. Li, J. Mak & Y. Wang (2023) [doi]
Ocean Modell., 183, 102204

Scalings for eddy buoyancy fluxes across prograde shelf/slope fronts

H. Wei, Y. Wang, A. L. Stewart & J. Mak (2022) [doi]
J. Adv. Model. Earth. Syst., 14(12), e2022MS003229

Research Areas


Eddy parameterisation

One of the focus of the group is on mesoscale eddy parameterisation arising from baroclinic turbulence, particularly on the energetically constrained parameterisation GEMOETRIC. Research activities include evaluating the impact on the modelled ocean circulation, on constraining the unknown parameters/processes associated with eddy energetics, and on maintaining/developing/implementing the relevant codes in global circulation models.

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Inverse methods / state estimates

We deploy and develop code/models for tackling optimisation, inference and/or data assimilation problems in the ocean context. Current activities including constraining uncertain parameters associated with eddy energy constrained parameterisations, inference of uncertain physical processes in the South China Sea, employing both the Firedrake and MITgcm ECCO framework. Outlooks include uncertainty quantification and biogeochemical applications.

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Chaotic / turbulent stirring

Stirring (to highlight the central role played by advection) of tracers is intimately linked to eddy parameterisations, as well as having implications for modelling biogeochemistry, ecology and pollutant dispersion. We are particularly interested in the Lagrangian point of view for dispersion, in quantifying dispersion via methods in dynamical systems and/or more recent Bayesian methods, and the associated computational methods.

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Theoretical fluid dynamics (mostly GFD, some MHD)

A focus we have is on baroclinic lifecycles, baroclinic turbulence, wave/eddy-mean interaction and shear flow instabilities to complement the modelling work on eddy parameterisation. Current work involves employing optimisation principles in relation to baroclinic equilibration, baroclinic instabilities under the GEOMETRIC framework, as well as symmetry breaking in waves and instabilities.

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Current team



Supreme lab manager

A manifestation of the fluid state.


Julian Mak

Assistant Professor + code monkey

The group's code-fixer. See personal website for proper content.

Favourite fish: Ducks

Han Seul

Han Seul Lee

PhD student (since Sep 2020; internship at WMO Feb 2022 to Jan 2023)

Han Seul is currently researching the South China Sea circulation, using a finite element method that utilises Firedrake. Her fascination is with simple models, and the degree to which they do (and do not) reflect the real world. She received her MPhys degree from the University of Oxford, where she studied the Antarctic Circumpolar Current using an eddy-parameterizing model, looking at different parameterization schemes.


Ruan Xi (阮曦, Bobo)

MSc student (Jan - Jun 2020), PhD student (since Sep 2020)

Bobo's interest is in biophysical interactions in the ocean. She obtained a MSc degree in Environmental Health and Safety from HKUST. Before that, she gained experiences in biological science from Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences.


Yongsu Na

PhD student (since Sep 2020; visitor at the CRIOS group Jul to Dec 2022)

Yongsu's main interest is a clear understanding of the natural phenomena associated with the ocean. He received his BSc and MEng from Korea University. He worked with Prof. Sangyoung Son on storm surge prediction using Delft3D and tropical cyclone prediction using echo state networks. He is currently working on the ocean mesoscale eddy parameterization using inverse methods and MITgcm. Along with his research, he enjoys playing sports (football, swimming, gym training) and skateboarding.


Yan Fei Er (嚴菲兒)

PhD student (since Feb 2021; Anita Conti fellowship to the MEOM group Sep to Dec 2023)

Fei Er's research interest is on the applications of machine learning methods to understanding oceanic mesoscale eddies. Fei Er obtained a MSc degree in Environmental fluid mechanics from the University of Grenoble Alpes, and another in Physical oceanography from the University of Bretagne Occidentale, France. Hobbies include swimming and hiking, undertaking a long-distance trail at least once a year.


Dan Bartley

Research Assistant (Jan 2022 - Jul 2022), MPhil student (since Sep 2022)

Dan’s research interest lies in the physical interactions between natural environments and engineering interventions. He obtained a MEng degree in Civil Engineering from Imperial College London and has research experience in sediment transport, wetland management and artificial reefs. After work, Dan’s hobbies include hiking, video games and making music.


Floriane Océane Sudre

Regular visitor (since Jul 2022)

Floriane is currently a PhD student at the Mediterranean Institute of Oceanography in Marseille and was previously a research assistant in HKUST. Her research interest is at the interface between physical ocean processes and environmental issues, such as marine pollution and impacts on ecology. She holds a MSc in Engineering from France, and a MSc in Environmental Science, specializing in Climate Physics, from the University of Copenhagen. For her Master's thesis she studied the impact of lateral and bottom frictions on the Swedish Gullmars fjord under Prof. Markus Jochum supervision. Aside from ocean research, she loves running in the jungle, swimming in the sea, taking care of her garden and eating fresh figs.


Lee Ho Ching (李皓澄, Jonathan)

PhD student (HKPFS awardee; since Feb 2024)

Jonathan has a keen interest in studying Earth Science related problems using computational methods. He obtained both BSc Geophysics and MSc Applied Computational Science and Engineering degree from Imperial College London, in which he gained experience in applying numerical modelling and machine learning to various aspects of Earth Science, including geophysical fluid dynamics. Currently, he is using Firedrake / Thetis for storm surge inversion and ocean-related optimisation problems.


Wu Yue (吳越, Virryna)

Post-doc (since Feb 2024)

Virryna's interest lies in understanding the ocean processes at high latitudes, including sea ice change, ocean circulations, air-sea interaction, and climate change. She holds a PhD from the University of East Anglia, where her research delved into the ocean response to Arctic sea ice retreat using coupled climate models in subpolar regions such as the Nordic Seas, Barents Sea, and Svalbard. Prior to that, she obtained a MRes degree in Ocean Sciences from the University of Southampton, with research experience in Arctic upper ocean circulation, particularly in the Beaufort Gyre. Outside of work, Virryna enjoys photography, cooking and baking.

Dearly departed


Wang Huanhuan
(Sep 22 - Feb 23)


Gautam Kumar
(Mar 21 - Sep 22)
Faculty in IcfaiTech Hyderabad


Liu Yongqi
(Sep 20 - Aug 22)
MPhil student
RA at Xiamen University


Haruki Saegusa
(Jul 21 - Feb 22)
UG researcher
Student at HKUST


Floriane Océane Sudre
(Mar 20 - May 21)
RA + PhD
PhD in Marseille


Chinmayee Mallick
(May 20 - Mar 21)
Research Assistant
Research Assistant at PolyU


Ellie Ong
(Oct 20 - Jan 21)
Visiting scholar


(Jun 18 - Jun 19)
Streetcat, stayed in Oxford


(Feb 18)
Honourary member