Unique Waves

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Unique Waves
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Storm Surges

• Waves are carried/pushed into shallow water by
  storms, hurricanes, and strong winds
• Their length can be several hundred km, and they
  can persist for hours

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• They are especially destructive when they are in
  phase with high tide
• They can increase the normal water level by an
  average of 3 m

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Internal Waves

• These are waves below the surface that are caused
  by different water densities
• They travel more slowly than surface waves, but
  can have a much larger height
• Surface waves 30 m/s
• Internal waves 1 m/s
• Internal wave height can reach 100 m

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• Internal waves are detected by buoys and also
  from satellite photos
• From the surface, they appear as slow moving oily
  slicks
• They can be caused by submarines, and from ship
  propellers

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Why are Internal Waves Important?

• Military submarines can be detected by looking
  for internal waves
• Biology internal waves bring nutrients to the
  surface
• Climate researchers internal waves can cause
  vertical mixing of cold and warm water

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• Ships entering fjords (long narrow inlet with
  steep sides) often found speed was dramatically
  reduced. No matter what the wind speed, or the
  state of the tide, ships found it nearly
  impossible to make normal headway. It was the
  presence of internal waves that slowed them down.

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Rogue/Freak Waves

• Waves are able to pass through each other, and
  come out unaffected when they separate
• However, when 2 or more waves coincide, a new
  higher crest is formed temporarily
• This overlap of waves is called a rogue or freak
  wave

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• Rogue waves can be 4x higher than a normal wave,
  reaching a maximum known height of 34 m

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• When 2 or more waves meet, interference occurs
• Constructive interference when 2 or more wave
  crests overlap to form huge waves
• Destructive interference when the crest of one
  wave coincides with the trough of another they
  cancel each other out

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