CR2025_06 Cross-shelf transport processes in a changing climate

Lead Supervisor: André Palóczy Filho, National Oceanography Centre

Email: apaloczy@noc.ac.uk

Co-supervisors: Jeffrey Polton, National Oceanography Centre; David Ferreira, Department of Meteorology, University of Reading; Diego Bruciaferri, Met Office Hadley Centre

Understanding and predicting the exchange of nutrients, heat, and planktonic organisms between the open ocean and the coast is important for human activities. Transport of water between the deep ocean and the shallower shelf seas is limited by the physics of ocean currents on the rotating Earth, which tend to flow along seafloor topographic features rather than across them. Transports across topography occur through a range of coexisting processes that are difficult to detangle, and accurately quantify, using ocean measurements alone. This limits our ability to understand and predict how climate-scale changes in deep North Atlantic circulation impact the shallow coastal ocean around the UK. Often, computer simulations are necessary to answer questions about these societally relevant but elusive processes.

However, simulating these relatively fast-evolving and patchy cross-slope ocean transports realistically is made difficult by finite computing resources. Understanding the physics of flow across topography is thus required for evaluating and improving ocean simulations. This project will advance our understanding of cross-shelf exchange processes by examining them in new high-resolution models of the Northwest European Shelf (NWES) around the UK. Figure 1 shows an example of typical model fields resolving some of the circulation around the NWES.

This is an exciting opportunity to apply physical insight and analytical mathematical skills to advance our mechanistic understanding of societally relevant ocean processes. Specifically, we will study cross-shelf exchange mechanisms by developing coastal numerical models for past, present and future climate forcing scenarios. The goal will be to use semi-idealised simulations of the NWES forced by output from global climate simulations to study the localisation of different cross-slope transport processes under different climate driving regimes. The student will examine changes in processes such as wind patterns over the shelf, exchanges of heat and freshwater with the atmosphere, deep-ocean forcing along the shelf edge, and mixing by coastal trapped waves or internal tides. This analysis will help identify dominant processes, laying the groundwork for a more detailed dynamical analysis of individual mechanisms using simplified numerical experiments or semi-analytical models.

The student will be based at the National Oceanography Centre (NOC) in Liverpool and will have the opportunity to do a three-month internship (completed in two visits) at the UK Met Office (UKMO). During the internship, the student will work closely with Dr. Diego Bruciaferri on running and understanding high-resolution models of the NWES based on existing implementations that have been developed and validated operationally for decades at the NOC and UKMO (e.g., Graham et al., 2018).

Training opportunities:

This project will train the student in the fundamentals of ocean dynamics, and numerical modelling. This training will allow the student to network themselves both in the operational/climate modelling and the dynamical oceanography communities across the institutions involved, and to integrate the EU-wide “Nucleus for European Modelling of the Ocean” (NEMO) community. It will thus place the student in an excellent position to advance their career in these fields, whether in industry or in academia.

Student profile:

This project would be suitable for an independent and mathematically oriented student with a degree in oceanography, meteorology, applied mathematics, physics, or a similarly strongly quantitative degree in the physical sciences.

Please note: For international candidates, this project will be hosted at University of Reading under lead supervision of David Ferreira

Co-Sponsorship details:

The project will receive a CASE award from the UK Met Office Hadley Centre.

References:

• Graham et al. (2018): AMM15: a new high-resolution NEMO configuration for operational simulation of the European north-west shelf. Geoscientific Model Development. https://doi.org/10.5194/gmd-11-681-2018
• Tonani et al. (2019): The impact of a new high-resolution ocean model on the Met Office North-West European Shelf forecasting system. Ocean Science. https://doi.org/10.5194/os-15-1133-2019