PhD Title: Transition to Turbulence in Flow over Rough Topography in the Southern Ocean
Supervisors: Dr Ali Mashayek (Imperial College London), Dr John Taylor (University of Cambridge), Professor Martin Siegert (Imperial College London)
Understanding the distribution and uptake of heat, carbon, and other tracers in our oceans is of great importance in climate models. It is an emerging picture that deep ocean turbulence exerts a control on the global overturning circulation through water mass transformation by diapycnal mixing at rough bottom topography and boundaries. Such small scale turbulence and even the relevant topographic features are often of a size unresolvable in global climate models, so effective parametrisation of these processes is essential, requiring advanced physical understanding.
Geostrophic motions flowing over rough topography in the energetic Antarctic circumpolar current are known to be an important source of mixing, through both locally breaking lee waves and non-propagating vortical motions. This project investigates the impact of these mechanisms on turbulent breakdown near rough bottom topography in order to better understand mixing characteristics in the Southern Ocean.