1. "Waves beneath the Sea" Phenomenon Physics Field Experiment Teaching Aspects

2. Dan Kelley Oceanography Dept. Dalhousie University http://www.phys.ocean.dal.ca/ ~kelley/ papers/ presentations/ 2001/ AST

3. "Dead" water Boat slows to a crawl...... surfing internal wake Nansen observation 189x Ekman explanation 1904

4. External and Internal Waves: restoring forces External waves: gravity g Internal waves: reduced gravity g=g  /  0

5. Physics of Waves Restoring force...... key to all oscillators!

6. Class Experiment [1]

7. Class Experiment [2]

8. Internal Waves in Atmosphere [1] Wave crests... rising air... condensation...... clouds.

9. Internal Waves in Atmosphere [2]

10. Banded Surface Slicks Convergent zones over troughs Sweeps oil into lines Visible by eye, radar, satellite, etc.

11. Ocean from Airplane

12. Ocean from Space

13. Ship Radar Internal waves yield banded slicks...... banded roughness...... surface signature of internal waves

14. SurfaceTidal Bore

15. Physics of (Tidal) Bore

16. Other Surface Bores [1]

17. Other Surface Bores [2]

18. Peter Galbraith PhD at Dalhousie Mixing, internal waves, estuarine physics Works at DFO in Quebec

19. Internal Tidal Waves

20. Chopper - a new type of ship!

22. Daniel Bourgault PhD at McGill Estuarine physics, ocean modelling, internal waves Works with me at Dalhousie

23. St. Lawrence Est. Internal Wave

24. Modelled Internal Wave

25. View from Shore

26. St. Lawrence Estuary

27. Geometrically Corrected View

28. Enhanced View

29. Internal Waves on Rotating Planet Wave "phase" goes one way...... wave "energy" goes another! Important to climate...

30. Scientific Summary Ocean/atmosphere has internal as well as external waves These waves may break...... causing ocean mixing...... affecting biology,... affecting chemistry,... affecting climate...

31. Teaching Summary Explains cloud patterns Explains "dead water" Illustrates universality of Physics (here, across Ocean & Atmosphere) Illustrates idea of restoring force Illustrates resonance