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