PHYSICAL OCEANOGRAPHY Tides

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PHYSICAL OCEANOGRAPHYTides

• GEOL 1033
• (Lesson 31)

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NEWTONS LAW OF GRAVITY

• Mm x Me
• Force of gravity F G
  -----------------------------
• d2
• where G is the gravitational constant
• Mm is the mass of the Moon
• Me is the mass of the Earth
• d is the distance between Earth and Moon
• Both revolve counterclockwise around a common
  centre of mass which is located within the mantle
  of Earth, so the Moon revolves around Earth in
  27.3 days, while Earth appears to wobble.
• Suns tidal forces are only about 47 that of
  Moons because the Moon is much closer even
  though it is much less massive.

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FORMATION OF TIDAL BULGES
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EARTHS ROTATION BENEATH TIDAL BULGES
Ebb tide
Flood tide
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THREE TYPES OF TIDES

• Semidiurnal
• Diurnal
• Mixed

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WORLD DISTRIBUTION OF THE 3 TYPES OF TIDES
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ORIGIN OF SPRING TIDES
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ORIGIN OF NEAP TIDES
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Eastern North American Tidal Ranges

• Microtidal 0 to 2 m
• Mesotidal 2 to 4 m
• Macrotidal gt 4 m

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HIGHEST TIDES IN THE WORLD

• Bay of Fundy (possibly also Ungava Bay, northern
  Quebec
• Compare tides between Horton Bluff (near
  Wolfville) and Halifax
• Note difference in ranges, tidal range
  categories, tide type

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LOW vs HIGH TIDE - Bay of Fundy

• Halls Harbour, NS, postcard

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BAY OF FUNDY
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TIDAL BORE
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ANNAPOLIS TIDAL GENERATING STATION
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BAY OF FUNDY
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