Theoretical Studies of Eddy Mixing

The overall goal of this study is to understand how material is transported by fluctuating motions in the ocean and the atmosphere. The project involves creating a number of models which can be run in real-time and can be used to illustrate visually the distinction between stirring and diffusion and the rapidity by which both together can homogenize a tracer. The approach can help in the understanding of the importance of eddies and weather systems in determining the transports and distributions of pollutants, components of ecosystems, heat, and ozone. The models will be made available on the web as well as in an interactive textbook on numerical fluid mechanics. The project includes training of a graduate student.

This project will investigate eddy mixing processes using idealized flow models for which the diffusion can be precisely controlled. The specific aims of the study are to contribute to improved understanding of: (1) the ways in which fluxes are non-local (i.e., depend on more than just the value of the gradients of the mean at the point of interest), (2) the effects of inhomogeneities both in the means (where the non-local nature of stirring comes into play) and in the eddy properties, and (3) how fluxes for reacting fields such as biogeochemical variables differ from passive tracers. Simulations together with analytical methods will be used to gain a deeper insight into the processes acting and the interplay among them.