An Estimate of the Isopycnal Diffusion Tensor Based on Particle Statistics

• Main Author: Riha, Stefan
• Format: Thesis
• Language: English
• Published: 2010
• Subjects: Course of study: MSc Climate Physics; North Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/11436/; https://oceanrep.geomar.de/id/eprint/11436/1/master.pdf

The quality of eddy ux-gradient parametrizations in models with coarse resolution depends on whether the generated diffusivity is similar to that of reference solutions produced by eddy resolving models. It is therefore essential to accurately describe the transport properties of eddy resolving ocean models. This thesis is a survey of the lateral transport of passive tracers induced by mesoscale eddies in the velocity field of a 1/12° numerical model of the North Atlantic. Statistical tools are used to relate particle trajectories of Lagrangian floats to the effective eddy diffusivity: Both Taylor's theory of turbulent dispersion, which forms the foundation for the analysis, and further refinements thereof, are discussed and used for computations. The underlying theories rely on several restrictive assumptions about the statistics of the flow field, and one objective of this thesis is to make the reader aware of how difficult an interpretation of the results can be.