Apparaît dans la collection : 2026 - T2 - WS2 - Instabilities and transitions in geophysical flows

We first investigate numerically the vanishing-viscosity limit of a two-dimensional wind-driven ocean model. Instead of forming a large-scale condensate, the flow remains strongly out of equilibrium, organizing into a highly energetic turbulent vortex gas coexisting with western-intensified gyres. When stratification is introduced, coherent Gulf Stream–like jets emerge and can dominate the large-scale flow. We map the phase diagram governing their existence within a two-layer quasi-geostrophic model. Guided by this framework, we present high-resolution simulations with a more comprehensive ocean model, suggesting that increased upper-ocean stratification, an inevitable consequence of global warming, can destabilize the Gulf Stream Extension.

Co-authors: Lennard Miller, Bruno Deremble