Speaker: Remi Tailleux (University of Reading)
Title: Dynamical and thermodynamic consequences of coupling between salinity and nonlinearities of the equation of state on our theoretical understanding of the ocean circulation and mixing
To a large extent, most of our theoretical understanding of geophysical fluid dynamics tends to rely on the use of approximated equations of state (linearized, perfect gas assumption, etc.), which also often neglect the role of water in the atmosphere or salinity in the ocean. As a result of such approximations/assumptions, all of the key concepts playing a central role in the theory of the large-scale oceanic and atmospheric circulations (such as potential vorticity, available potential energy, heat, isentropic surfaces, neutral surfaces, etc.) are in general unambiguous and well-defined. All these concepts become ambiguous and sometimes even ill-defined, however, when the nonlinearities of the equation of state are re-introduced along with the dependence on chemical composition, raising the question of how best to extend such concepts to realistic fluids. In this talk, I will review the nature of the difficulties pertaining to the oceanic case and discuss some of the approaches that I and others have developed over the past decade or so to resolve them.