Sabrina SPEICH

Understanding Ocean Mesoscale Eddies 


The ocean, like the atmosphere, is a fundamentally turbulent system. As a consequence, intense nonlinear interactions that give origin to fine-scale structures such as eddies, fronts, jets and filaments, dominate the ocean circulation. Mesoscale eddies are ubiquitous in the ocean, and typically exhibit different characteristics to their surroundings, allowing them to transport properties such as heat, salt and carbon around the ocean. This takes place everywhere in the world’s ocean and at all latitude bands.

Most of the mesoscale eddy energy is generated by instabilities of the mean flow, and by air-sea interactions. They can feed energy and momentum back into the mean flow and help drive the deep ocean circulation and they are suspected to be the key element in transporting and mixing water properties as they propagate in the ocean, playing a significant role in the global budgets of ocean tracers and climate. They have also a major impact on ecosystems, and society by affecting fisheries, offshore platforms etc. Moreover, increasing evidences point out at intense air-sea interaction at smaller scale than synoptical, impacting throughout the whole troposphere.

With the advent of ocean satellite observations, eddies have appeared as omnipresent. However our theoretical understanding of many processes involving mesoscale eddies remains inadequate. This is particularly true for their 3D subsurface characterization and the phenomenological understanding of their role in the global ocean circulation, in the transport of properties (heat, salt, carbon, oxygen, nutrients, and other biogeochemical elements), and in how they shape air-sea interactions, climate and ecosystems. This represents an acute weakness in our present comprehending of ocean and atmosphere dynamics and their role in shaping ecosystems and climate variability. A better qualification and assessment of these processes and feedbacks at these scales is of capital importance to correctly address global change.

The overarching goal of this project and related international actions is to address these issues and make a leap forward on their understanding taking advantage of the different partners expertise and by creating a new synergistic approach.

©Thomas BLANKE 2018