Thesis Role Of The Ocean Mesoscale on The Transport Of Heat Towards The SEA Ice In Polar Regions M - F H/F Ifremer

Deadline for applications: 20/04/2026

Who are we ?

You will be based at Ifremer within the Ocean and Climate' team at the Laboratory of Space and Physical Oceanography (LOPS), located at the Brest Iroise Technology Park in Plouzané, France. The Ocean and Climate team comprises several experts working on research topics closely linked to the PhD project, such as mesoscale dynamics and heat transport. You will also benefit from activities carried out as part of the cross-cutting research theme on polar research, which brings together researchers specialising in polar regions to exchange scientific ideas and collaborate.

The PhD project forms part of HEAT-UP, a four-year project led by C. Dufour and funded by the ANR JCJC. HEAT-UP involves several partners at national (Mercator Ocean International, CERFACS, LOCEAN-IPSL) and international (Delft University of Technology, GEOMAR) levels, with whom the student will have the opportunity to interact.

The computing resources required to carry out the project's analyses will be provided by the local Datarmor cluster and the Météo France cluster. You will be assisted by LOPS research engineers in carrying out these analyses.

What is the topic of the thesis?

Both the Arctic and Antarctic sea ice are currently retreating and are predicted to further shrink into the 21st century. Reductions in sea ice have major implications on the climate, the ecosystems, and on human societies. Reliable projections of sea ice are thus crucial to help our societies in making informed decisions for climate change mitigation and adaptation. The sea ice retreat is due in part to the ocean that brings relatively warm waters from the low to the high latitudes. In particular, mesoscale processes (10-100 km) are thought to play a determining role in transporting heat towards polar regions. Yet, it remains unclear how ocean mesoscale impacts the pathways of these warm waters en route to the poles, the magnitude and variability of poleward heat transport, and how it contributes to transferring this heat up to the sea ice. This knowledge gap is due to the sparsity of observations in polar regions and the limited resolution of numerical models at high latitudes.

This project proposes to advance our understanding of the role of the ocean mesoscale on heat transport from the subpolar regions to the sea ice. This will be achieved by using a hierarchy of high-resolution ocean-sea ice models ; from the eddy-permitting (1/4°) that is currently used in some climate models to the eddy-rich (1/36°) resolution that resolves most of the mesoscale features but whose cost remains prohibitive to climate models. The analyses will allow the quantification of the contribution of the mesoscale to the poleward heat transport and the vertical transport below sea ice, and to the pathways of the relatively warm waters heading to the poles. We will leverage similarities between the two polar regions to make advances on the characterization and quantification of the impact of mesoscale processes on heat transport in the context of sea ice decline. Doing so, the project will inform the tuning and development of parameterizations of mesoscale processes in sea ice regions in ocean models and the interpretation and deployment of observations in polar regions.

What will your mission and activities be?

• Investigate the impact of resolution on the spatial and temporal relationship between poleward heat transport and sea ice on seasonal to decadal timescales, and quantify the contribution of transient mesoscale eddies to the poleward heat transport in both polar regions using the hierarchy of ocean-sea ice models at various resolutions.
• Examine how mesoscale processes impact the pathways of warm waters en route to the polar regions.
• Quantify mesoscale eddy contribution to vertical and lateral heat transport within the mixed layer below sea ice.

Key words

Polar regions, heat transport, mesoscale, numerical modelling, sea ice.

How are your activities organized?

• Reading and analysis of the bibliography on the PhD topic.
• Analyses of the numerical model output through developing Python scripts.
• Design of diagnostics and experiments to test hypotheses.
• Writing of publications in peer-reviewed scientific journals.
• Participation to meetings, conferences and workshops at the local, national and international levels.
• Presentation of results in seminars, meetings, conferences and workshops.
• Participation to outreach activities is highly encouraged.