The Movement of Ocean Water

Carin Miranda Smyrna Middle School

6-12007

Currents• Surface Currents• Deep Currents

Surface Currents

• Streamlike movements of water that occur at or near the surface of the ocean.

• Can be several thousand km.• Controlled by three factors:

• Global winds• Coriolis effect• Continental deflections

Global Winds

• Winds blowing across the Earth’s surface.

• Near the equator they flow east to west.

• Near the poles they flow west to east.

Coriolis Effect• The curving of moving objects from

a straight path due to the Earth’s rotation.

• Ocean currents in the Northern Hemisphere turn clockwise.

• Ocean currents in the Southern Hemisphere turn counterclockwise.

Continental Deflections

• When surface currents meet continents, they deflect, or change direction.

Deep Currents• Streamlike movements of ocean water

far below the surface.• Form where water density increases.

• Less dense water always floats on top of denser water

• Two main factors• Temperature• Salinity

Surface Currents and Climate

• Can warm or cool costal areas year round.

• This helps to stabilize climate.• They can also disrupt climates.

• Can cause mudslides, flash floods, and even droughts.

Parts of Waves• Crest

• top of the wave.• Trough

• bottom of the wave.• Wavelength

• crest to crest or trough to trough• Wave height

• From crest to trough

Wave Formation and Movement

• The movement of water in an ocean is an illusion.

• The water just rises and falls in circular movements.

Specifics of Wave Movement

• Formula• Wavelength (m) = wavespeed (m/s)

• Waveperiod (s)

• Wave period is the time between the passage of two crests at a fixed point.

What can cause Waves?

• Wind• Underwater earthquakes• Landslides• Impacts by cosmic bodies

Deep water waves and Shallow water waves

• Deep water waves- waves that move in water that is deeper than ½ of their wavelength.

• Shallow water waves- waves that move in water that is shallower than ½ of their wavelength.

• As waves move closer to shore they slow down and build up height.

Open ocean Waves

• Form in the open ocean• Whitecaps- white, foaming waves

with very steep crests- usually during storms.

• Swells- rolling waves that move in a steady procession across the ocean.

Tsunamis

• Form when large volumes of water are suddenly moved up or down.

• As they get closer to the shore their wavelength shortens and their wave height increases.

• Caused by• Underwater earthquakes• Volcanic eruptions• Landslides• Underwater explosions• Impact of a meteorite or comet.

Storm Surge

• Local rise in sea level• Caused by strong winds• This dumps huge amounts of water

onshore.• This is what causes most of the

damages in a hurricane, not the winds.

• Daily movements of ocean water that change the level of the ocean’s surface.

• Influenced by the sun and moon.

Lure of The Moon

• The gravity of the moon pulls on every particle of the Earth.

• This is more noticeable in liquids.• The moon is smaller than the sun, but it

is closer, therefore it has more

of an effect on the tides.

High Tide

• The moon’s pull is strongest on the part of the Earth facing the moon and on the opposite side of the Earth

• These are the two places where you will see high tides.

High Tide is on the right and left in this picture.

Low TideHalf way in between the two high tides is where you will find the low tides.

In this picture low tide is at the top and bottom of the picture.

Spring Tides

• When the Earth, moon, and sun are all in alignment.

• Have maximum daily tidal range (good surfing).

• Occur during new and full moons.• Occur every 14 days.

Spring Tides

Neap Tides

• The sun, moon, and Earth form a 90 degree angle.

• Minimum daily tidal range.• Halfway between the Spring

tides.

Neap Tide