Transcript Chapter 37

Chapter 37
The Atmosphere, the Oceans, and
their Interactions
Changing Temperatures
1.
2.
Oceans are important for keeping Earth’s
temperature and climate under control
What does it mean that earth has large heat
capacity?



Slow to heat up or cool down
Need a lot of heat/energy to heat or cool down
the earth
Especially true near water
Fill in the Blank
3.
______________________________
__ is an example of a city with
moderate temperatures because of
the ocean.
The Evolution of the
Atmosphere
4. Hydrogen and Helium are believed to have
been in the first atmosphere
5. Some scientists believe no oxygen was
present
6. What caused the second stage in the
formation of the atmosphere?
a.
b.
c.
Gases escaped through volcanoes/fissures
85% water vapor, 10% CO2, 5% nitrogen
Still no free oxygen
The Evolution of the
Atmosphere
7. Free oxygen may not have appeared
until green algae and stromatolites
(basic plants) appeared
*Why did oxygen come with the plants?
8. Free oxygen produced allowed an
Ozone layer to form.
9. Ozone filters ultraviolet radiating which
keeps the earth cool.
10. Heat keeps gas molecules from falling
out of the air.
11. Air grows cooler and thinner at higher
elevations
12. Density is greatest at the bottom due
to gravity.
Air Components
13. Air has weight and exerts pressure on the
earth’s surface called atmospheric pressure
14. Weight of air on oceans keeps the ocean
from boiling away.
15. Nitrogen (78%) and Oxygen (21%) are the
most abundant gases in the air.
1.
2.
Can you guess the next two gases?
Argon & Carbon Dioxide
Structure of the
Atmosphere
16. The atmosphere is classified in layers
17. Weather occurs in the troposphere
a.
Contains 90 percent of atmosphere’s mass
b.
Extends 8 to 16 km up depending on region
c.
Temperature decreases gradually (at top = -50!)
18. Why do airliners fly at the top of this layer?
a.
Avoid weather
b.
Less bumpiness
Structure of the
Atmosphere
19. Stratosphere is above the troposphere
a.
b.
c.
goes up to 50 km
Contains the ozone layer
Temperature increases (-50 to 0)…. Why?
20. Mesosphere extends up to 80 km
a.
Temperature decreases again
b.
Meteor and rock fragments burn up here
21. Thermosphere extends up to 500 km
a.
Space shuttles orbit here
b.
Where auroras happen
Structure of the Atmosphere
22. Ionosphere is an ion-rich area within
the thermosphere and uppermost
mesosphere
a.
b.
Ions produced from interaction between
solar radiation and atoms in the
atmosphere
Produces auroras near the magnetic
poles
23. Above 500 km is the exosphere
a.
Very thin
b.
Merges into space
Assignment
Create a visual map of the atmosphere
layers
For each layers, use some sort of
combination of pictures and colors to
show the characteristics of that layer
Example: The troposphere is where
weather occurs so you could draw a
thunderstorm happening in that layer

See next slide
Solar Energy
THINK! Why are the areas near the
equator warmer than the polar regions?

1.
2.
More direct sunlight!
Surface temperatures depend on the angle
of the sun’s rays to the earth’s surface
Being at an angle spread the same energy
over a larger area.
The Seasons
1. The US and Canada have distinct
seasons because they have variations
in the angle of the sun
2. Summer = Sun’s rays closest to
perpendicular ( )on a spot on the
earth
3. More oblique (at an angle) rays come
6 months later = winter!
Seasons
4.
5.
6.
7.
Earth is actually farthest from the sun when
the Northern Hemisphere has summer
Angles matter more than distance is
SEASONS!
Equinoxes - are days of equal hours of
daylight and night (mid-Sept. & mid-March)
At the poles there are 6 months with 24
hour days or nights
Terrestrial Radiation
1. The earth absorbs some energy from
the sun
2. Part is reradiated back into space =
terrestrial (earth) radiation
3. Terrestrial radiation actually directly
warms the lower atmosphere; why
higher = colder
Terrestrial Radiation
4.
5.
6.
7.
Temperature depends on the net effect of
radiation coming in and radiation going out
Direct sunlight= surface absorbs more
energy than it emits which causes the earth
to warm
Night is cooler because earth sends back
more energy than it takes in
Cloudy nights are warmer because clouds
block incoming or outgoing radiation
Where do the
sun’s rays go?
What happens
to the majority of
the sun’s
radiation?
What percent is
reflected back
into the
atmosphere and
back into space?
What percent is
absorbed in
some part of the
earth?
What are some
things solar
radiation on
earth is used
for?
Greenhouse
Effect
1. What happens when the
terrestrial radiation can’t get
out?
2. Actually beneficial to a certain
degree


Keeps the earth warm
Too much can be a problem
3. Largest gases involved in
global warming?



Water vapor!
Carbon Dioxide – levels on the
rise
Methane & CFC’s
37.4 Driving Forces of
Air Motion (Standard 5b)
THINK! What is a convection current?
Why do we call our ovens convection
ovens?
Warm air rises, cools down, then falls
 Creates a current that evenly cooks food

1. Convection currents in the atmosphere
create wind
a.
How would you define wind?
a.
b.
c.
Air in nearly horizontal motion
Wind is generated due to pressure
differences in the atmosphere
Difference in pressure between two spots
called a pressure gradient
2. Underlying cause of air circulation is
uneven heating of earth
a.
b.
c.
d.
Air warmer at equator; warm air rises
Cools as circulates to Poles; cold air falls
Cooler air moves back toward equator
If earth were still there would be one
circulation pattern in the south one in the
north
Why don’t the
air patterns on
earth actually
look like this?
Answer: The
rotation of the
earth!
3. The earth rotates; affecting the air movement
a.
b.
c.
What would happen if you played catch on a merrygo-round
Coriolis effect – apparent deflection due to the
rotation of the earth
Coriolis effect causes wind to go right in Northern
hemisphere and left in Southern hemisphere
i.
ii.
Faster wind = greater deflection
Deflection greatest at poles; decreases at equator
Global Circulation Patterns
1.
Cells of circulation move heat over earth
At equator air flows straight up
a.
i.
ii.
iii.
Called doldrums
Cool as air rises, causes rain
Makes tropical forests found at equator
Moves North or South
b.
i.
ii.
iii.
iv.
At ~30 degrees, cools enough to fall down
Warms as it falls
Creates hot, dry air
Deserts characteristic
Trade winds & Westerlies
2. Air moves south from the north and
north from the south
a.
b.
Deflected westward
Produces trade winds
3. Air moving north from the north and
south from the south
a.
b.
Deflected eastward
Produces Westerlies
Other Winds
4. Polar regions have cold air
a.
b.
Cold dry air meets warm, moist air at 60
degrees north and south
Creates storms in these regions
5. Mountains, valleys, deserts, forests,
bodies of water all influence how wind
blows
Oceanic Circulation
Oceanic Circulation Lab
Keep water in containers
 Clean up any spills
 Follow directions and be sure and mark
which color ice cube is which

Answer pre-lab questions, then come
up and get the equipment and ice cubes
you need
Tuesday, February 10
Word:

Relative humidity: ratio of the amount of
water vapor in the air compared to the
amount the air can hold at a given
temperature
Warm-Up:
Which is more dense (sinks), cold water or
warm water?
 Which is more dense, salty water or fresh
water?
 How does that relate to ocean circulation?
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Philosophical Chairs
You must participate at least once to get
credit
You must fill out the sheet and turn it in
to get credit
If you talk without being called on, you
will get points docked
Rules of Engagement
Topic Statement
Global warming is a natural thing and
we should not be worried about its
effects.
Wednesday, February 11
Jet streams: high speed winds in the
upper troposphere
Warm-up:
What animal did Al Gore say you should
always rescue?
 Explain how a convection cycle is made.

Ocean Circulation
Two types of currents move the ocean
Wind-driven surface currents
 Density-driven deep water currents

Density is controlled by two things
Temperature
 Salinity – how salty a mixture is

Salinity
Salinity is a measure of the amount of
salts dissolved in 1000 g of seawater
The ocean is about 3.5% salt
 Kept about the same by fresh water
coming in and evaporation

Layers of the Ocean
Ocean has layers:
surface zone, transition
zone, and deep zone

What are the
characteristics of water as
you go deeper?
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More pressure
Colder
Remembering your lab,
which is more dense and
sinks, cold or warm
water?
Which is more dense, salt
water or fresh water?
Surface Currents
Wind effects water over a short distance
Over a long distance Coriolis effect comes into
play:
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Causes water to spiral in a circular gyre
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Clockwise in Northern Hemisphere
Counterclockwise in Southern
Gyres circulate heat around the world
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Warm water from Mexico moves up US East Coast
Cold water from Alaska moves down along US West Coast
Deep Water Currents
Deep currents are driven by gravity
Deep water flow like a large conveyor belt
Starts at the north:
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Sea water freezes, leaves salt behind
Increased salinity = increased density
Water Sinks
Deep water flows along bottom, creating conveyor
belt – Starts in N. Atlantic, to Antarctica and back
up