Motion of the Ocean • Chapter 3
Do Now • 1) Draw a diagram of an ocean profile • Label the 3 layers of the ocean (with depth marked) • Label the permanent thermocline in the appropriate layer • 2)What is the coriolis effect?
Surface currents • Caused by the wind pushing the sea surface. • ** surface layer does not travel in the same direction as the wind** • They move at a 45 degree angle
Ekman Transport • The effect of the wind decreases with depth • Depth of a few hundred meters, the wind is not felt at all • Ekman layer- affected by the wind
Gyres • Trade winds and surface current patterns • Trade winds move toward to equator • Equatorial currents (produced by wind) move parallel to equator • Coriolis effect--- wind driven surface currents combine into huge circular systems • Fig 3.22
Pacific Garbage Patch • Think, Pair, Share • Youtube Garbage patch
Water transport • Water is particularly good at transporting heat • Why? • Warm currents on western sides of gyres carry vast amounts of solar heat from the equator to higher latitudes. • Cold currents on eastern sides
Temperature of Sea Surface • Surface temperature is higher on western sides of oceans • Surface temperature is cooler on the eastern side
Waves • Crest – Highest part • Trough- lowest part • Height – Vertical distance between crest and trough • Wavelength – distance from crest to crest • Period – time it takes a wave to go by any given point
Tides • Rising and falling of sea • Influences near shore sea life (expose and submerge organisms) • What causes tides? • Gravitiational pull of moon and sun, rotations of earth, moon and sun
Earth and Moon • Moon and earth rotate around a common point** • The point is their combined center of mass • Centrifugal force balances attraction between the two
Centrifugal force • Centrifugal force and moon’s gravity are not in perfect balance everywhere on earth’s surface • Side of the Earth nearest the moon, water gets pulled to moon • Side away from the moon, centrifugal force pushes water away
Rotation of the Earth • The earth spins like a top on its own axis • High tide – occurs when the point is under the bulge • Earth takes 24 hrs to complete a rotation • 2 high tides and 2 low tides a day (most places)
Sun on tides • The sun also produces tidal bulges like the moon • When the sun and the moon are in line with each other (full moon and new moon) effects are added • Tidal range is LARGE
Tides Spring tide Neap tide Occurs when the sun and moon are at right angles to each other Tidal range is small Moon is at first and third quarters • Occurs when the sun and moon are in a line • Occur twice a month throughout the year • Moon is full
Exit Ticket • 1) Two high tides and two low tides during a day • 2) Type of tide that occurs when sun and moon are in a line • 3) type of tide that occurs when sun and moon are at 90 degrees • A) neap tide • B) semidiurnal • C) spring tide • 4) What is Ekman transport? • 5) What is a gyre?