Internal waves are found below the ocean surface. They travel and break in a similar way to the surface waves we are all familiar with at the beach, but may have much larger amplitudes (10-100s of metres) and wavelengths (several kilometres). Recently, indirect measurements of the vertical velocities associated with internal waves have been made using a new technology: ocean gliders (Fratka Williams et al., 2011). Seagliders are autonomous vehicles that profile the upper kilometre of the ocean, transmitting their data and receiving commands via iridium mobile phone. By accurately measuring their rate of descent/ascent and modelling the flow past the glider, we can estimate the vertical velocity of the surrounding water. Vertical velocities are normally quite small (~ mm/s) in the ocean, but in internal waves they can be some tens of cm/s.

UEA has four operational Seagliders and we have carried out research campaigns in the North Atlantic, Indian Ocean, North Sea, and Southern Ocean. See our website, www.ueaglider.uea.ac.uk, for more details of these missions and to view data being sent back in real time. During some of these missions, gliders have passed through internal waves large enough to arrest their descent or ascent, so vertical velocities must have been in excess of 20 cm/s. This project will use these datasets to identify internal wave variability, the spatial and temporal distribution, and interactions with other physical and biogeochemical processes.

Your primary dataset will be obtained as part of the ‘Ocean2ice' project, an intensive study of ocean processes on the continental shelf and slope of the Amundsen Sea, Antarctica. Two Seagliders will be deployed at the experiment site during a research cruise in early 2014. You will join the UEA Seaglider piloting team that control the glider fleet and learn about data processing, calibration, and quality control. Internal wave variability in the dataset will be identified using harmonic and spectral analysis techniques and the spatial/temporal distribution compared with ray-tracing approaches and the output of numerical models.

This project offers flexibility for you to get involved in other aspects of multidisciplinary Seaglider research as your research interests develop. For example, you might explore the influence of the internal waves on turbulent mixing, nutrient fluxes, and phytoplankton blooms.

For this project we seek a motivated student with a good physical science degree (e.g., physical oceanography, meteorology, physics, environmental sciences; minimum requirement: 2.1). Experience of programming (e.g., Matlab, Fortran) is an advantage. You do not need to have studied ocean science previously, training in physical oceanography will be provided. We will expect you to participate in research cruises, including the Antarctic campaign, and present your scientific findings at workshops and conferences. You will gain transferable skills in data analysis and synthesis, computer programming, and scientific communication.

Frajka-Williams, Eleanor, Charles C. Eriksen, Peter B. Rhines, Ramsey R. Harcourt, 2011: Determining Vertical Water Velocities from Seaglider. J. Atmos. Oceanic Technol., 28, 1641–1656.