2004 HOUGHTON LECTURES SERIES
PROFESSOR CHRIS GARRETT
School of Earth and Ocean Sciences
University of Victoria, Canada
All lectures will be given in
Building 54, Room 915
Monday, April 12, 4 pm
1) Some Dynamics of Sea Straits.
Flows through straits can be strongly nonlinear (in the sense that the current speed can be comparable with the speed of waves) as well as being influenced by stratification, rotation, mixing, and friction. This complexity suggests a need for numerical models. However, it is still of immense value to have guiding principles such as those of hydraulic control and maximal exchange. These concepts can be blurred considerably as soon as one moves away from simple "slab" models, in which the flow is typically treated as being made up of uniform layers; but progress is being made.
Concepts of geostrophic and hydraulic control for barotropic flow will be reviewed, followed by a brief discussion of the effects of friction, entrainment, and shear. This leads into some discussion of exchange flows, with an emphasis on the rich dynamics of the Strait of Gibraltar.
Finally, the need will be discussed for parameterizations of things like internal and lateral friction to be based on direct observations rather than circumstantial evidence.
Wednesday, April 14, 12 noon
2) Why Ocean Tides are Back in Fashion.
The apparent predictability of ocean tides led to their neglect, but they are now back in fashion for a variety of reasons. Even the reasons for large coastal tides in some regions are a matter of debate; a review will presented of the way in which simple models of resonance can be instructive. However, the main reason for renewed interest is that internal tides in the ocean appear to be a prime mixing agent. A small part of this problem will be reviewed, dealing with topography steeper than the critical slope. Finally, the prospects of harnessing tides for electric power generation will be discussed, with comments and new results on the use of turbines in strong currents rather than dams at the mouth of bays.
Thursday, April 15, 4 pm
3) Energy from the Sea: Some Anecdotes and Issues.
One of the main current reasons for the study of the oceans is that they play a role in climate. However, oceanographers can also contribute to society by evaluating ways in which climate change can be mitigated or avoided. In a very selective discussion of some of the issues that arise in interactions with the energy sector, oceanographic input to some problems of offshore oil development will begin a discussion; but then comments will be presented on renewable sources of energy such as waves and tides. Finally, allowing for the possibility that nuclear power will be revived, some aspects will be mentioned of radioactive waste disposal in the ocean. The main purpose of the talk is to encourage students and others to become involved in some of these practical issues.