Waves beneath the Sea - PowerPoint PPT Presentation

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Waves beneath the Sea

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Estuarine physics, ocean modelling, internal waves. Works with me at Dalhousie. St. Lawrence Est. ... Ocean/atmosphere has internal as well as external waves ... – PowerPoint PPT presentation

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Tags: beneath | ocean | sea | waves

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Title: Waves beneath the Sea


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

2
Dan KelleyOceanography Dept.Dalhousie
Universityhttp//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 ggDr/r0

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!
21
(No Transcript)
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
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