Ocean Currents

Warm currents flow away from the equator.

Cold currents flow toward the equator.

Ocean Currents

SunWindCoriolisGravity

Factors Influencing Currents

Energy from the Sun heats the water.Warm water is less dense than cold water.

Warm water rises, and cold water sinks.

As warm water rises, cold water moves in to replace it.

Sun

Wind

Water moves from high pressure to low pressure areas (just like wind).

Winds blow across the surface of the water, causing friction.

The water piles up because the surface currents flow slower than the winds.

Wind

As water piles up and flows from high to low pressure, gravity will pull down on the water.

This forms dunes or mounds of water.The Coriolis Effect causes the water to

curve.

Gravity

Causes water to:Curves to the right in the Northern Hemisphere

Curves to the left in the Southern Hemisphere

The Coriolis Effect

The Coriolis Effect(draw this)

Affects 10% of oceans’ waterMaximum depth of 400 mCaused by the surface wind patterns.

Surface Currents

Surface Currents

A strong surface currentBegins at the tip of FloridaFlows up the eastern coastline of the

U.S. Crosses the Atlantic OceanCauses warmer climate in NW Europe

Gulf Stream

Dunes or mounds of water at the surface and they flow in circles

Produce enormous circular currents Five major locations:

North Pacific – clockwise-cw South Pacific – counterclockwise-ccw Indian Ocean – ccw (counterclockwise) South Atlantic – ccw (counterclockwise) North Atlantic – cw (clockwise)

Gyres

Gyres

Climate InteractionBoth Galveston, Texas, and San Francisco, California, are adjacent to bodiesof water. Galveston typically has warm humid weather, while San Francisco Is usually cool. Why is this?

Climate Interaction

The Pacific Ocean currents in this area are colder causing the air mass to take on the same characteristics (mP).

Climate Interaction

The Gulf of Mexico is warm and humid, so the air mass originating there would be warmer.

Surface waters blown by the wind.Less dense surface water moves off shore and cold, deep, denser waters come to the surface to replace them.

Upwelling

Upwelling

http://www.youtube.com/watch?v=XV90dy0ns1U lab demo

http://archive.org/details/CIL-10019 NASA http://

www.classzone.com/books/earth_science/terc/content/visualizations/es2405/es2405page01.cfm animation

http://www.youtube.com/watch?v=w_8mw-1HYFg Bill Nye 2 minutes

Upwelling

The Great Ocean Conveyor:Helps maintain Earth’s Balance

Make up about 90% of oceans’ water Differences in density cause them to move. Differences in density are related to

temperature and salinity. (salty) At high latitudes, they sink deep into the

ocean basins. Temperatures are so cold, they cause the

density to increase.

Deep Water Currents

Wind pushing surface water allowing denser water to surface, causing a convection current.

Denser water sinking (cold from polar region) and less dense water rising (equatorial region).

Reflective Question-How are ocean currents produced?