1. Physical Oceanography
Internal Waves
Mike Brown
Physical Oceanography
Fall 2014

2. Waves form at the interface between fluids of different densities.
Tank demo: note the slow speed and large amplitude of the internal wave.

3. Long wave approximation: (similar to shallow waves).
Internal waves typically have slow velocities and large amplitudes.
Density
Depth
Karp-Boss et al. (2009)

4. Frequency is bounded by f and N (horizontal/vertical group velocity).
When the ocean is continuously stratified, the direction of wave propagation is dependent on frequency.
Frequency is bounded by f and N (horizontal/vertical group velocity).
Group velocity can be in a different direction than phase velocity.
Density
Depth
Knauss (2005)

5. A dominant source of ocean mixing.
Generated primarily by 1) tidal flow over seafloor topography, 2) wind.
A dominant source of ocean mixing.
Jayne et al. (2004)

6. Internal waves can be detected at the sea surface.
Knauss (2005)

7. References:
Alford, M. H., MacKinnon, J. A., Zhao, Z., Pinkel, R., Klymak, J., & Peacock, T. (2007). Internal waves across the Pacific. Geophysical Research Letters, 34(24).
Franks, P. J., & Franks, S. E. (2009). Hands-on oceanography: Mix it up, mix it down: Intriguing implications of ocean layering. Oceanography, 22(1), 228.
Jayne, S. R., Laurent, L. C. S., & Gille, S. T. (2004). Connections Between Ocean Bottom Topography and Earth’s Climate. Oceanography, 17(1).
Karp-Boss, L., Boss, E., Weller, H., Loftin, J., & Albright, J. (2009). Teaching Physical Concepts in Oceanography: An Inquiry Based Approach. Oceanography, 22(3).
Knauss, J. A. (2005). Introduction to physical oceanography. Waveland Press, Inc..
Kundu, P. K. (1990). Fluid Mechanics. Academic Press, Inc..
St Laurent, L., Alford, M. H., & Paluszkiewicz, T. (2012). An introduction to the special issue on internal waves. Oceanography, 25(2),