Transcript Ocean Currents - Atlanta Public Schools

Ocean Currents
6th Grade Earth Science
Sutton Middle School
Fill in
the
blanks!
Land has a lower specific heat!
• Land heats up _______ than water, but it also
cools off more __________.
• Oceans heat _______, hold heat well, and give
off heat slowly.
– In winter, the ocean acts like a heater because it keeps
the coastal climate ___________
– In summer, the ocean acts like an
_______________as cooler ocean air moves inland
through convection currents.
– Land near the ocean is often _______ in winter and
8
cooler in the________.
Land has a lower specific heat!
• Land heats up faster than water, but it also cools
off more quickly.
• Oceans heat slowly, hold heat well, and give off
heat slowly.
– In winter, the ocean acts like a heater to faster cooling
land.
– In summer, the ocean acts like an air conditioner as
cooler ocean air moves inland through convection
currents.
– Land near the ocean is often warmer in winter and
cooler in summer.
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Ocean Currents
• Mass movement or flow of
ocean water
• River within the ocean
• Two types
–Surface and Deep
Surface Currents
Link
• Horizontal, stream-like
movements of water that occur at
or near the surface of the ocean
• Can reach depths of several
hundred meters
• Example: Gyres
Surface Currents
•Controlled by three factors
–Global winds
–Coriolis Effect
–Continental Deflections
Surface Currents
• Global Winds
–Cause surface currents to flow in
the direction the wind is blowing
–EX: Jet Stream
• Coriolis Effect Link
–The apparent curving of moving
objects due to the Earth’s rotation
Surface Currents
• Coriolis Effect
–Northern Hemisphere = clockwise
–Southern Hemisphere = counter
clockwise
• Continental Deflections
–Shape of continents change the
direction of current flow
Deep Currents
• Stream like movement of ocean
water far below the surface
• Caused by
– Changes in density
–Change in temperature
–Change in salinity
What Effects Deep Currents?
• Change in temperature
–Decreasing the temperature
of water increases density
• Change in salinity
–Increasing the salinity of
water increases density
Currents and climate
• Warm water currents
–Bring warm water to colder
regions
Currents and climate
• Cold water currents
–Bring cold water to warmer
regions
Why are Ocean Currents
Important?
• They make the average temperatures of climates more
•
•
similar
– This is on a large scale
Ocean air holds a lot of water vapor – so there is
more rain at the coast
Currents redistribute heat throughout the globe
– Example: Gulf Stream brings warm air into England,
making it warmer
Question 1
•What is a surface current
and what causes them?
Answer
•Surface currents move
water horizontally – parallel
to the Earth’s surface
•They are powered by wind
Question 2
•What is the Coriolis
Effect?
Answer
•The Coriolis effect is the
shifting of winds and
surface currents caused
by Earth’s rotation.
Question 3
•What is upwelling?
Answer
•Upwelling is a vertical
circulation in the ocean
that brings deep, cold
water to the ocean
surface.