FEIT Research Project Database

Ocean convection and turbulent mixing on the Antarctic Margins


Project Leader: Cat Vreugdenhil
Staff: Bishakhdatta Gayen
Student: Bahman Ghasemi
Primary Contact: Cat Vreugdenhil (cat.vreugdenhil@unimelb.edu.au)
Keywords: computational fluid dynamics; fluid dynamics; Oceanography ; stratified flow; turbulent convection
Disciplines: Mechanical Engineering
Domains:

Ocean convection is crucial for heat and CO2 uptake and storage, and the transport of nutrients in our global oceans. Near the Antarctic Margins, convection removes heat from deep ocean currents that could otherwise melt ice shelves. In addition, it produces dense shelf water that feeds into the lower limb of the globally-spanning Meridional Overturning Circulation. However, convection on the Antarctic margins is extremely difficult to observe in-situ and cannot be resolved in large-scale ocean models. This research group has a strong history of using cutting-edge, turbulence-resolving numerical simulations to model convection in the ocean, with a new focus on convection on the Antarctic Margins.

The student will design, run, and analyse numerical simulations of ocean convection on the Antarctic Margins. Existing Fortran and Python codes will be used for the simulations and post-processing. The student will become familiar with the solver, run parallelised simulations, learn flow visualisation techniques and fluid physics involved with this complex flow. This project will include the opportunity to run simulations on Australia’s fastest supercomputer (NCI’s Gadi).

This project has valuable opportunities for collaboration with world-class observationalists and ocean modellers. The numerical simulations will be compared against recent observations taken by collaborators in the Antarctic Margins Group (UTas, CSIRO, UNSW, and more). Our collaborators at Princeton University and ANU will also help compare with ocean parameterisations, to add value to the project.

Related articles:

Hogg, A. M., & Gayen, B. (2020). Ocean gyres driven by surface buoyancy forcing. Geophysical Research Letters47(16), e2020GL088539.

Morrison, A. K., Hogg, A. M., England, M. H., & Spence, P. (2020). Warm Circumpolar Deep Water transport toward Antarctica driven by local dense water export in canyons. Science Advances6(18), eaav2516.

Sohail, T., Vreugdenhil, C. A., Gayen, B., & Hogg, A. M. (2019). The impact of turbulence and convection on transport in the Southern Ocean. Journal of Geophysical Research: Oceans124(6), 4208-4221.

Vreugdenhil, C., Gayen, B., & Griffiths, R. W. (2016). Mixing and dissipation in a geostrophic buoyancy?driven circulation. Journal of Geophysical Research: Oceans121 (8), 6076-6091.

Vreugdenhil, C., Gayen, B., & Griffiths, R. W. (2019). Transport by deep convection in basin-scale geostrophic circulation: turbulence-resolving simulations. Journal of Fluid Mechanics865, 681-719.

Vreugdenhil, C., Griffiths, R. W., & Gayen, B. (2017). Geostrophic and chimney regimes in rotating horizontal convection with imposed heat flux. Journal of Fluid Mechanics823, 57-99.

Convective regions (surface transformation) on the Antarctic continental shelf.
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