Transcript Ocean Currents - Mrs. NormanScience

Ocean Currents
Ocean Currents
Warm currents flow away from the
equator.
Cold currents flow toward the equator.
Factors Influencing Currents
Sun
Wind
Coriolis
Gravity
Sun
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.
Wind
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.
Gravity
 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.
The Coriolis Effect
 Causes water to:
 Curves to the right in the Northern
Hemisphere
 Curves to the left in the Southern
Hemisphere
The Coriolis Effect
(draw this)
Surface Currents
 Affects 10% of oceans’ water
 Maximum depth of 400 m
 Caused by the surface wind patterns.
Surface Currents
Gulf Stream
 A strong surface current
 Begins at the tip of Florida
 Flows up the eastern coastline of the U.S.
 Crosses the Atlantic Ocean
 Causes warmer climate in NW Europe
Gyres
 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 Interaction
Both Galveston,
Texas, and San
Francisco, California,
are adjacent to
bodies
of 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.
Upwelling
 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=XV90dy0n
s1U lab demo
 http://archive.org/details/CIL-10019 NASA
 http://www.classzone.com/books/earth_scien
ce/terc/content/visualizations/es2405/es2405p
age01.cfm animation
 http://www.youtube.com/watch?v=w_8mw1HYFg Bill Nye 2 minutes
The Great Ocean Conveyor:
Helps maintain Earth’s Balance
Deep Water Currents
 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.
Reflective QuestionHow are ocean currents produced?
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).