The dynamics of jets in geophysical turbulence

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Research Areas: Fluid dynamics and Aerodynamics.It is well known that rotating turbulent flows, in the presence of a planetary vorticity gradient, have a strong tendency to organise into zonal (east-west) jets. Examples in Nature include the banded jets on the giant planets, particularly Jupiter and Saturn, and those observed in the Southern ocean.The aim of the project is to improve our theoretical understanding of the physics of these jets by studying their formation in a hierarchy of models ofincreasing complexity and realism. One simple, widely explored model is the single-layer model of quasi-geostrophic beta-plane turbulence. The project will exploit methods from non-equilibrium statistical mechanics to understand and interpret the jet formation behaviour in this model. Of particular interest is a recently discovered 'migrating jet' regime, the dynamical origin of which is hitherto unexplained.The project will continue by considering results from more sophisticated three-dimensional models. In the case of Jupiter, the recent Juno mission has established that the jets penetrate deep into the interior of the planet. The question of how well state-of-the-art general circulation model results capture the correct jet depth will be explored, with a particular focus on the extent to which the Juno results can be used to constrain model parameters.