When the wind blows over the ocean surface, the rotation of the Earth means that oscillations in the water are set up at a particular frequency (the Coriolis frequency) that varies with location on the Earth's surface. Oceanographers call these 'near-inertial' waves, and they can propagate from the sea surface deep into the ocean where they can (we think) break just like surface waves. The breaking of these wind-driven near-inertial waves is believed to be one of the most important energy sources for generating mixing in the ocean. Mixing is important in determining the large-scale ocean circulation and its ability to transport heat and influence our climate. Even though progress has been made over the last decade, many fundamental questions regarding the near-inertial energy in the ocean remain open. For example, there is still lack of quantitative assessment of how much of the near-inertial energy input at the sea surface is actually available for mixing in the ocean interior.

This project aims to answer some of these fundamental questions by examining the life cycle of the wind-driven near-inertial energy in the ocean, from its generation, subsequent propagation to its ultimate dissipation. You will learn to tackle this problem using state-of-the-art high-resolution ocean circulation models in both idealized and realistic setup. You will also have opportunities to participate in research cruises to make relevant measurements to test your theory and model results. The outcome of this studentship is expected to advance our knowledge of the wind-driven near-inertial energy in the ocean and its role in sustaining deep ocean mixing, and help to guide future parameterizations of ocean mixing in climate models. The project will provide you with a thorough training in ocean dynamics, air-sea interactions, numerical modelling and data analysis, and with opportunities to collaborate with scientists in GEOMAR (Germany) and MIT (USA).

Requirements: We seek an enthusiastic candidate with strong scientific interests and self-motivation. She/he will have at least a 2.1 honours degree in mathematics, physics, oceanography, meteorology, and climate science with good numerical skills.

Alford, M.H. (2003), Improved global maps and 54-years history of wind-work on ocean inertial motions, Geophysical Research Letters, 30, L1424, doi:10.1029/2002GL016614.

Ferrari, R., and C. Wunsch (2009), Ocean circulation kinetic energy: Reservoirs, sources, and sinks, Annual Review of Fluid Mechanics, 41, 253-282.

Zhai, X., R.J. Greatbatch, and J. Zhao (2005), Enhanced vertical propagation of storm-induced near-inertial energy in an eddying ocean channel model, Geophysical Research Letters, 32, L18602, doi:10.1029/2005GL023643. (AGU highlighted paper)

Zhai, X., R.J. Greatbatch, and C. Eden (2007), Spreading of near-inertial energy in a 1/12th degree model of the North Atlantic Ocean, Geophysical Research Letters, 34, L10609, doi:10.1029/2007GL029895. (AGU highlighted paper)

Zhai, X., R.J. Greatbatch, C. Eden and T. Hibiya (2009), On the loss of wind-induced near-inertial energy to turbulent mixing in the upper ocean, Journal of Physical Oceanography, 39, 3040-3045.