Ch. 3: Chemical & Physical Features of Seawater & the World Ocean

Motion in the Ocean

I. Surface CirculationA. Coriolis Effect

1. Earth is round and rotating, so anything that moves over its surface tends to turn rather than move in a straight line

2. Deflects things right in the N. Hemisphere and left in the S. Hemisphere.

I. Surface CirculationB. Wind Patterns

1. Winds are driven by the sun’s heat.

2. Most solar energy is absorbed at the equator.

3. Warm air rises, and cool air gets sucked in to replace this warm air.

4. Coriolis effect causes the wind to be bent instead of moving in a straight line.

I. Surface CirculationB. Wind Patterns

5. Trade Winds: Winds from 0O-30O N & S of the equator

6. Westerlies: Winds from 30O-60O N or S of the equator.

7. Polar Easterlies: Winds from 60O N or S of the equator.

I. Surface CirculationC. Surface

Currents1. The major wind

fields of the atmosphere push the sea surface, creating currents.

I. Surface CirculationC. Surface Currents

2. Equatorial Currentsa. Produced from the trade winds moving towards the Equator,

producing winds parallel to the Equator at the sea surface.

I. Surface CirculationC. Surface Currents

3. Gyresa. Upper part of the

water column which is affected by the wind.

I. Surface CirculationC. Surface Currents

4. El Niño-Southern Oscillation

I. Surface CirculationC. Surface Currents

5. Role of surface currents is to transport of heat from the Equator to the poles

6. Warm current run up W sides of ocean.

7. Cold currents run down E sides of oceans.

II. Waves

A. Undulations that forms as a disturbance moves along the surface of the water.

II. WavesB. Wave Terms

1. Crest: highest part of the wave.

2. Trough: lowest part of a wave.

3. Height: vertical distance between the crest & trough.

4. Wavelength: the distance between two crests or two troughs.

5. Period: the time a wave takes to go by any given point.

II. WavesC. Waves begin to form when the wind

blows.D. Faster & longer wind = larger waves.E. Fetch: the span of open water over

which a wave blows.

II. WavesF. Seas: while the wind is blowing it pushes

wave crests up into sharp peaks and “stretches out” the troughs.

G. Swells: waves with smooth and rounded crests.

II. WavesH. Surf: cresting & breaking of a wave.

III. Tides

A. The rising and falling of the sea surface in a rhythmic pattern.

III. Tides

B. Why are there tides?1. Gravity of the moon,

the sun, and Earth

2. The earth and moon revolve around a center point of gravity.

III. Tides

B. Why are there tides?3. Side nearest earth,

moons gravity is stronger & pulls the water towards the moon.

4. Side away from the moon, centrifugal force dominate & pulls the water away from the moon.

III. Tides

B. Why are there tides?5. The earth also spins,

so high tide is when earth is under this bulge, and low tide occurs when it is away from the bulge.

6. A full tide circle takes 24 hours and 50 minutes.

III. Tides

B. Why are there tides?7. Tidal range: the difference in water

level between successive high and low tides.

III. TidesB. Why are there tides?

8. Spring tides: sun & moon line-up, creating a larger tides (new moon & full moon).

9. Neap tides: sun & moon are at right angles, partially canceling each other out (lower high tides) (1st & 3rd quarters).

III. TidesB. Why are there tides?

8. Spring tides: sun & moon line-up, creating a larger tides (new moon & full moon).

9. Neap tides: sun & moon are at right angles, partially canceling each other out (lower tides) (1st & 3rd quarters).

III. TidesB. Why are there tides?

8. Spring tides: sun & moon line-up, creating a larger tides (new moon & full moon).

9. Neap tides: sun & moon are at right angles, partially canceling each other out (lower high tides) (1st & 3rd quarters).

III. Tides

C. Tides in the Real World1. Semidiurnal tides

III. Tides

C. Tides in the Real World2. Mixed Semidiurnal tides

III. Tides

C. Tides in the Real World3. Diurnal tides