Download 16.1 16.2 Ocean Circulation Waves Tides

Starter
Complete the #1-5 on page 3 of the sheet
entitled, “Standardized Test Prep”.
Answer all questions to the best of your
ability. You may write on this sheet.
When finished, turn your paper face down
on your desk and wait patiently.
Starter
1.
2.
3.
4.
What is the most abundant salt in
seawater?
Evaporation does not lead to a decrease
in _________ of seawater.
Name the 3 layers of ocean water
structure.
Why is salinity expressed in parts per
thousand instead of percent?
Objectives p. 30
1.
2.
3.
4.
Explain how surface currents develop.
Describe how ocean currents affect
climate.
State the importance of upwelling.
Describe the formation of density
currents.
Warm water flows
toward poles
Dense water
moves toward
_________
Temperature
________ and
_________ increases
Density __________
Cold water
__________
Upwelled water
_________
The cycle __________
page 29
Vocabulary (Index Cards)
208. Current
209. Gyre
210. Coriolis
Effect
211. Upwelling
212. Surface Current
213. Density Current
214. Wave Height
215. Wave
Length
216. Wave Period
217. Tide
218. Tidal Range
219. Spring Tide
220. Neap Tide
Ocean Circulation
http://upload.wikimedia.org/wikipedia/com
mons/thumb/e/e0/Clouds_over_the_Atlantic_
Ocean.jpg/275pxClouds_over_the_Atlantic_Ocean.jpg
 Ocean
water is constantly in motion,
powered by many different forces.
Winds generate surface currents and
produce waves.
 Circulation in the ocean is important for
ocean mixing and recycling nutrients
Surface Circulation
 Ocean
currents are masses of ocean
water the flow from one place to another.
 Ocean currents can be at the surface or
deep below.
 The amount of water can be large or
small and the creation of these currents
can be simple or complex.
Surface Currents
 Surface
currents are movements of water
that flow horizontally in the upper part of
the ocean’s surface
 Surface currents develop from friction
between the ocean and the wind that
blows across its surface
Surface Currents
 Gyres
(gyros=circle) are large whirls of
water within an ocean basin
 5 main gyres

North Pacific Gyre, South Pacific Gyre, North
Atlantic Gyre, South Atlantic Gyre and
Indian Ocean Gyre
Surface Currents
https://www.windows2universe.org/earth/Water/images/surface_currents_sm2.jpg
Surface Currents
 Wind
is the force that creates surface
currents, but other factors influence the
movement of water

Coriolis effect
 Coriolis
Effect- currents are deflected
away from their original course because
of Earth’s rotation


Currents in Northern Hemisphere
deflected to the right
Currents in Sourthern Hemisphere
deflected to the left
Draw these diagrams
on page 29.
http://oceanservice.noaa.gov/education/kit
s/currents/media/coriolis_effect_240.gif
http://www.nc-climate.ncsu.edu/secc_edu/images/coreff.jpg
Ocean Currents and Climate
 When
currents from low latitude areas
move into higher latitudes they transfer
heat from warmer to cooler areas on
Earth


Cold currents begin in cold high-latitude
regions
As cold water currents move toward the
Equator they help moderate the warm
temperatures of adjacent land areas
 OCEAN
CURRENTS PLAY A MAJOR ROLE
IN MAINTAINING EARTH’S HEAT
BALANCE
Upwelling
 Winds

can cause vertical movements
Upwelling is the rising of cold water from
deeper layers to replace warmer surface
water
• Important because it brings a greater
concentration of dissolved nutrients to the
surface
http://www.piscoweb.org/files/image/research/Coasta
l-Oceanography/upwelling/upwelling.gif
Deep Ocean Circulation

Density currents are vertical currents of
ocean water


Denser water sinks and slowly spreads out
beneath the surface
An increase in seawater density can be
caused by a decrease in temperature or an
increase in salinity
Most water in deep ocean density currents
begins in high latitudes
 Density currents can also be a result of
increased salinity because of evaporation

Deep Ocean Circulation

A model of ocean circulation is similar to a
conveyor belt that travels from the Atlantic
Ocean through the Indian and Pacific
Oceans and back again
http://static.ddmcdn.com/gif/ocean-current-7b.jpg
http://weloveteaching.com/0bio105/le
ctures/earth/waterupdown.jpg
Post-Test (page 30)
1.
2.
3.
What is the Coriolis effect?
How does the coriolis effect influence
the direction of surface currents
flowing in the ocean?
During an El Nino event, the upwelling
of cold, nutrient-rich water stops in
areas off the coast of Peru. How might
this affect the food web in this area?
Starter
Complete the #1-4 on page 4 of the sheet
entitled, “Standardized Test Prep”.
Answer all questions to the best of your
ability. You may write on this sheet.
When finished, turn your paper face down
on your desk and wait patiently.
Starter
1.
2.
3.
4.
Circulation in the ocean is important for
doing what?
What are horizontal movements of water
in the ocean called?
What are large whirls of water in an
ocean basin called?
Currents in the northern hemisphere are
deflected to the right due to what?
16.2 Waves and Tides
Objectives
Page 32
1.
2.
3.
Describe how ocean waves get their
energy.
Describe how energy moves through a
wave.
Explain the forces that produce tides.
Waves
 Most
ocean waves obtain their energy
and motion from the wind
 When a breeze is less than 1.8mph only
small waves appear
http://nees.oregonstate.edu/killer_wave/wave.jpg
Wave Characteristics





Crest top of a wave
Trough lowest point of a wave
Wave height distance between a crest and
trough (vertical distance)
Wave length distance between 2 crests or
distance between 2 troughs (horizontal
distance)
Wave period the time it takes one full wave
(1 wavelength) to pass a fixed position
Wave Characteristics
http://lighthouse.tamucc.edu/dnrpub/forecasts/wave_2.png
Wave Characteristics
The height, length and period of a
wave depend on three factors

1.
2.
3.
Wind speed
Length of time the wind has blown
Fetch (distance the wind has traveled
across open water)
Wave Motion
 Waves
can travel great distances across
ocean basins
 In one study, waves generated near
Antarctica were traced as they traveled
through the Pacific Ocean


The water itself does not travel the entire
distance, but the WAVE DOES
Water particles pass the energy along by
moving in a circle (circular orbital motion)
Circular Orbital Motion
http://upload.wikimedia.org/wiki
pedia/commons/thumb/0/06/Wav
e_motion-i18n-mod.svg/300pxWave_motion-i18n-mod.svg.png

Circular orbital motion allows energy to move
forward through the water while the individual
water particles that transmit the wave move
around in a circle.
Breaking Waves
 As
long a wave is in deep water, it is
unaffected by water depth.
 When a wave approaches the shore, the
water becomes shallower and the wave
begins to “feel bottom”
http://www.s-cool.co.uk/alevel/assets/learn_its/alevel/geography/coasta
l-processes/wave-processes/2007-1022_113641.gif
Breaking Waves
 As
the speed of a wave decreases the
wave grows higher

Critical point is reached when the wave is
too steep to support itself and the wave
breaks
Sun, Moon, Tides
Tides
 Tides
are daily changes in the elevation
of the ocean surface


Caused by the gravitational attraction upon
Earth by the moon and the sun
2 forces that produce tides
• Gravity
• Inertia
Tides
http://oceanservice.noaa.gov/education/kits/tides/media/tide03_240.gif
Tides

Tidal range


Spring tides



Difference in height between 2 high tides or 2 low
tides
Tides that have the greatest tidal range
Occur during the full moon and the new moon
Neap tides


Smallest rise and fall in tidal level (small tidal
range)
Neap tides occur during quarter moons
Tides
http://upload.wikimedia.org/wikipedia/commons/c/cf/Chiswick_Eyot_channel_at_low_tide_vs_high_tide.jpg
LOW TIDE
HIGH TIDE
Tidal Patterns
3



main tidal patterns exist worldwide
Semidiurnal- 2 high tides and 2 low tides
each day (Atlantic Coast of the U.S.)
Diurnal- 1 high tide and 1 low tide each day
(northern shore of the Gulf of Mexico)
Mixed tides- inequality in high water heights
and low water heights (Pacific Coast of U.S.
and in other parts of the world)
Post-Test (page 32)
From where do ocean waves obtain their
energy?
2. Which celestial bodies influence Earth
tides?
3. What are the 3 types of tidal patterns?
Which pattern does Myrtle Beach
experience?
4. Two waves have the same fetch and were
created by winds of equal speed. Why
might one wave be higher than the other?
1.
Wave Characteristics
(page 31)