Project funded by the Make Our Planet Great Again program (2019-2024). Principal investigators: W.K. Dewar (Florida State University) and MEOM scientists. Collaborations in LOPS (Brest) and LMD (Paris).

Consistent OceaN Turbulence for ClimaTe Simulators

The Earth’s climate evolution and sensitivity to human influences strongly depend on the dynamics of the ocean, which absorbs most of the excess heat and greenhouse gases, redistributes them around the globe, and may eventually flux them back into the atmosphere. Numerical climate simulators now partially resolve the oceanic mesoscale turbulence (scales of ~100km, the strongest ocean variability process involved in climate dynamics) and provide more consistent solutions than their laminar predecessors.

The dynamical sources and spontaneous cascade of mesoscale turbulence towards larger scales are rather well known and simulated today. In contrast, the cascade of mesoscale toward finer, sub- mesoscale turbulence (scales of ~10km) represents a significant sink of kinetic energy, which is still crudely understood, quantified, and simulated. More importantly, the misrepresentation in ocean models of this small-scale energy sink adversely affects the ocean’s full energy spectrum, hence yields substantial inconsistencies in ocean-atmosphere models used for climate projections.

The CONTaCTS projects aims to study and parameterize this missing effect where it is critical: within the surface and bottom boundary layers of the ocean, where it interacts with the atmosphere and topography. We propose to develop such parameterizations for O(10km) resolution models, based on the analysis of existing O(1km) resolution North Atlantic simulations (eNATL60, see a relative vorticity snapshot in the figure below).

The CONTaCTS project team gathers experts in Geophysical Fluid Dynamics, submeso-/meso-scale turbulence, and high-resolution ocean modeling. The project will contribute to improve ocean models (in particular NEMO), future climate simulators, interpret and exploit future observations at very high resolution (SWOT satellite altimeter to be launched in late 2022), with foreseen benefits for operational oceanography.

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Contact : Thierry Penduff