Supervisors

Dr Marie-Jose Messias - University of Exeter - Faculty of Environment, Science and Economy

Dr Malcolm Woodward - Plymouth Marine Laboratory

Location:

Geography, Streatham, Exeter

The University of Exeter’s Department of Geography is inviting applications for a PhD studentship fully-funded by Faculty of Environment, Science and Economy to commence on 23 September 2024 or ASAP thereafter.  For eligible students the studentship will cover Home or International  tuition fees plus an annual tax-free stipend of at least £19,237 for 3.5 years full-time, or pro rata for part-time study.

Project Description:

This project aims to shed light on the spatiotemporal origin of the warming of the Atlantic part of the Southern Ocean by tracking back in time and space the heat uptake and redistribution by the world ocean using oceanic biogeochemical and transient tracers.

Knowledge about the ocean's absorption of 'excess' heat i.e., the heat that has accumulated in the Earth system as a result of anthropogenic greenhouse gas emissions, is essential for estimating future global warming. The oceans have absorbed ~90% of this excess heat. Of these, although they only occupy a quarter of the world's ocean surface, the seas surrounding Antarctica, known as the Southern Ocean (SO), are responsible for ~3/4 of this excess heat absorption. This important role of the SO in controlling ocean heat reservoirs is due to its unique circulation pattern and its role in ventilating a large part of the world ocean by forming the subtropical mode, the intermediate waters and the bottom waters. However, there are uncertainties about the history and redistribution of the excess heat, particularly in the deep ocean, which is poorly sampled below 2000 m depth and still mainly explored by ship hydrographic surveys.

You will use existing observational data from ship hydrographic surveys, world ocean data bases and synthetic data (General Circulation Model) and learn how to reconstruct historical Ocean Heat Content (OHC) change along those SO surveyed lines (Figure 1, Meijers et al., 2023) with state-of-the-art methodology and high-performance computers. The method assumes that tracer propagation in the ocean can be modelled by a Green’s Function that relates time-and-space by varying the surface boundary conditions to interior tracer distributions (Messias and Mercier, 2022).

You will quantify the associated uptake, transport and storage of heat. The analysis will provide insight into both 1) the time scales and the dynamics of the SO ventilation and 2) the regions of uptake and the redistribution of excess heat contributing to warming in the SO for past and future changes. The results of the tracer-based method will be analysed in synergy with other OHC inventories and the Coupled Model Intercomparison Projects Phase 5/6 models. 

This is an exciting multidisciplinary opportunity to contribute to leading-edge research in an important part of the world. The student will get a solid knowledge base from worldwide recognised scientists studying the ocean dynamics, polar ocean circulation and biogeochemistry, relating to our changing planet.  In particular, the student will have the opportunity to collaborate with the Laboratory for Ocean Physics and Satellite remote sensing  abroad and participate to conferences.

Entry requirements

Applicants for this studentship must have obtained, or be about to obtain at least a UK 2:1 honours degree, or its international equivalent in oceanography, physics, mathematics or computer sciences.

How to apply

Apply now

Online application requiring the upload of:
• CV
• Letter of motivation
• Transcript/certificates to date.
• Names of two referees. We will request references directly from your referees if you are shortlisted.
• If you are not a national of a majority English-speaking country you will need to submit evidence of your proficiency in English.

The closing date for applications is midnight on 23rd July 2024.

If you have any general enquiries about the application process please email PGRApplicants@exeter.ac.uk or phone 0300 555 60 60 (UK callers) / +44 (0) 1392 723044 (EU/International callers).  Project-specific queries should be directed to m.messias@exeter.ac.uk.

Summary