(Mathematics, Physics, Engineering)
Physical oceanography involves the study of the physical processes which occur in the ocean and their effect on climate, and the transport of pollutants and nutrients. Important processes include waves, currents, tides, and the transport of heat.
In the large oceans, the sun's heat, winds and the earth's rotation act to drive water towards the equator where it is warmed, and then poleward to be cooled through exchange with the atmosphere. The oceans form a key component of the earth's heat engine and are intimately coupled with climate change and large climatic events such as the El Nino. Questions about how and where oceans take up and store heat and greenhouse gases are being addressed by physical oceanographers through international long-term programs. Researchers measure sea levels and currents using satellites and instruments at fixed sites deep in the ocean. They also monitor salinity, temperature and concentrations of greenhouse gases in sea water to great accuracy, enabling detection and prediction of change. All of these measurements are combined and used in mathematical and super-computer models to help oceanographers understand and predict ocean circulation.
Large-scale circulation can also depend on processes at smaller scales, such as waves at the ocean surface and deep ocean turbulence, which act to distribute and exchange heat, momentum and gases with the atmosphere. The oceanographer may take measurements of waves from aircraft during intense storms, or work in the calm of a laboratory estimating mixing and turbulence in tanks of fluid.
The circulation along our continental shelves is no less important or fascinating. Wind-driven currents act to draw deep, nutrient rich water up into the coastal zone. Upwelled water fertilises microscopic marine plants which can bloom in great abundance and provide an important food source for fisheries. The effects of waves and currents determine the shape of beaches, the distribution of pollutants on the coastline, and the flushing and environmental health of bays and estuaries. Ocean circulation is also central to many of the problems confronting our environment, and the physical oceanographer of the future will collaborate with marine biologists, chemists, and engineers in the development of models that describe and predict the nature of our environment.
A strong background in mathematics, physics or engineering is required for oceanography. Given the enormous scope of the subject, the skills learned in basic training can be adapted to specialised fields. An undergraduate degree (preferably to honours level) can lead to employment as a scientist or research assistant in universities, government laboratories, environmental agencies, or other private industry. Postgraduate study provides opportunities to become leaders in research and in the management and monitoring of our marine environment.
Photos: (Top) Deploying of a CTD (conductivity, temperature, depth) device from a research vessel. (Bottom) Satellite images help physical oceanographers to understand the dynamics of ocean currents; this image is of the Leeuwin current off Western Australia.