Physical and acoustical oceanography
Lecturers: Dr Brendan McGann, Dr Alec Duncan
Location: Curtin University, Bentley Campus
Mode of Delivery: On-line
Physics and mathematics to first year university level.
To provide students with an understanding of the physical processes that occur in the oceans and the effects they have on the propagation of underwater sound.
The course will be broken into twelve modules, with the students completing one module per week. There will be two one-week breaks during the semester leading to a total duration of fourteen weeks.
Lecture material will be provided on-line and will be accessible to students via the Worldwide Web at any time of day. The on-line material will also guide students in their reading of the textbook and provide them with worked examples and exercises. Email discussion groups will be provided to allow students to interact with one another and a lecturer will be available to provide an immediate response to email queries at a prescribed time each week. Emails sent to the lecturer at other times will be responded to as soon as possible and in any event before the next scheduled weekly on-line email session .
Assessment will be by way of four assignments and a final test. Each assignment is worth 15% of the final mark and the test is worth 40%.
- Descriptive oceanography: General characteristics of the world’s oceans; properties of seawater and their typical distributions in the oceans; depth zones; stability; circulation and water masses; the deep circulation; thermoclines and thermohaline circulation; the mixed layer; edd ies; frontal zones.
- Theoretical background: Equations of motion; effects of rotation; geostrophic flow; effects of friction; wind driven flow; Ekman current.
- Waves: Linear wave theory; refraction; diffraction; finite amplitude effects; wave breaking; wave generation by the wind; wave spectra.
- Internal wave and tides: Barotropic and baroclinic waves in the ocean; Rossby waves; Inertial and buoyancy frequencies; Tide producing forces; ocean response to forcing; practical tidal analysis and prediction; tides in typical ocean regions; tidal currents; internal tides; internal waves.
- Oceanographic numerical modelling: Numerical methods; modelling ocean circulation.
- Marine instrumentation: Instrumentation for oceanographic measurements; measurement procedures.
- Relationships between water properties and sound speed: Effects of temperature, salinity and pressure.
- Ducting: Surface ducting; deep sound channel; polar ocean channel.
- Sea surface effects: Scattering from the sea surface; effects of bubbles on propagation and scattering.
- Ambient noise: Wind dependent noise; biological noise; noise from seismic events; traffic noise; other man-made noise; noise coherence.
- Shallow water effects: Seabed properties; acoustic properties of sediments; seabed roughness; acoustic bottom reflectivity.
- Meso-scale effects: Horizontal refraction; propagation through fronts and eddies; influence of Earth curvature; signal fluctuations and scattering due to random inhomogeneities; internal wave effects.
Assignments will cover material from the following modules:
Assignment 1: Modules 1 & 2
Assignment 2: Modules 3-6
Assignment 3: Modules 7-9
Assignment 4: Modules 10-12
The final test will cover material from all modules
The text for this unit is:
- S Pond and G L Pickard Introductory Dynamical Oceanography, 2nd Edition, Pergamon, 1983.
The following books are useful references:
- L E Kinsler et. al. Fundamentals of Acoustics, Wiley, 1982.
- H Medwin and C S Clay, Fundamentals of Acoustical Oceanography, Academic Press, 1998.
- R Urick, Principles of underwater sound for engineers, 3rd Edition, Peninsula Publishing, 1983.