Sofia Allende, a post-doctoral researcher at the IRPHE, invited by Baptiste Néel (MIO), will give a seminar on Friday 20 February 2026 à 13h00, at the OCEANOMED Amphitheatre, on the theme : Melting dynamics and mixing layer growth near the ice-ocean interface.
Abstract
At the ice-ocean interface, one of the key physical processes is double-diffusive convection, a mechanism describing the convective mixing of fluids driven by the interplay between salinity and temperature gradients. This phenomenon is thought to play a critical role in regulating the salt and heat balance in polar regions but remains poorly parameterized in global climate models. I will here describe recent numerical work using highly resolved simulations, where we study the melt-driven growth of temperature and salinity mixing layers beneath a rigid ice interface. By varying the ambient salinity and the salt diffusivity, we identify a transition from convective to diffusion-dominated dynamics close to the interface, which decouples the melting dynamics from the turbulent transport. We demonstrate that the mixing layer grows super-diffusively in all regimes, thereby challenging the commonly assumed picture of a fully diffusive regime at high salinity. These results highlight potential limitations of diagnostics based on fixed concentration thresholds in oceanographic applications.