Name _______________________________________
Period ______
Atmosphere Stuff
Read each topic and hi-lite/annotate
Answer practice questions to review your understanding
Watch videos and draw diagrams when required
WEATHER AND CLIMATE
Practice
We refer to the local, short-term conditions in an
area as weather. This includes temperature, humidity,
Which of the following is the best description of a region’s climate?
cloud cover, precipitation, wind speed, and
atmospheric pressure. But weather only happens on
A. The amount of rainfall that an area receives over a period of 1
time scales from seconds to days. The average
year.
weather in an area over a long period of time (at least
several decades) is called climate.
B. The average precipitation over a 1-2 year time period.
Climate is defined by temperature and
precipitation and is what determines plants in an area,
C. The average high temperature of a region.
which in turn, determines animals.
There are six different factors that affect the
D. The average temperature and precipitation over several
distribution of heat and precipitation around the
decades.
world, thus leading to varying climates. These six
factors are unequal heating of Earth by the Sun,
E. The average temperature and rainfall over a period of 1-2
atmospheric convection currents, the rotation of
years.
Earth, Earth’s orbit around the sun on a tilted axis,
ocean currents, and Earth’s topography.
We will start with general information about the
Answer: ________
atmosphere, then explore these six climatedetermining factors.
Take a deep breath. About 99% of the volume of air
you inhaled consists of two gases: nitrogen (78%)
and oxygen (21%). The remainder consists of water
vapor (varying from 0.01% at the frigid poles to 4%
in the humid tropics, for an average of about 1%),
0.93% argon (Ar), 0.039% carbon dioxide (CO2) and
trace amounts of dust and soot particles as well as
other gases including methane (CH4), ozone (O3),
and nitrous oxide (N2O).
Review Question:
The atmosphere is 78% nitrogen but it is in a form we are unable
to utilize. Describe how we are able to convert nitrogen gas (N2)
into a more useable form (use appropriate vocab, feel free to
draw diagram)
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EARTH’S ATMOSPHERE
The density of the gas molecules per unit of air volume
varies throughout the atmosphere because gravity pulls its gas
molecules toward the earth’s surface. About 75-80% of the
earth’s air mass is found in the atmospheric layer closest to
earth’s surface – the troposphere. This layer extends about 11
miles above sea level at the equator and 4 miles above sea
level over the poles. Most of the weather we experience
occurs in this layer. Air currents, winds, and concentrations of
CO2 and other greenhouse gases in the troposphere play a
major role in the planet’s weather and climate.
The layers of the atmosphere are based on differences in
temperature as altitude increases. Because of radiation from
Earth and the objects on it, the troposphere is warmer at sea
level (0 km altitude) and cools as altitude increases.
Moving away from Earth, the next layer of the atmosphere
is the stratosphere. The stratosphere contains a layer of air
with a high concentration of ozone molecules (O3), called the
ozone layer. Stratospheric ozone is formed when oxygen
molecules (O2) in this layer interact with ultraviolet (UV)
radiation from the sun. The ozone layer keeps about 95% of
the sun’s harmful UV radiation from reaching the earth’s
surface. This UV filtering effect allows life to exist on Earth
and protects us from sunburn, skin and eye cancers, cataracts,
and damage to our immune systems. This absorption of UV
also makes the stratosphere warm as altitude increases, a
trend opposite to that of the troposphere.
Above the stratosphere is the mesosphere and then the
thermosphere. Without any heat absorbing materials, the
mesosphere is the coldest layer of the atmosphere. The
thermosphere is sometimes broken down further into the
ionsphere (an area of highly charged particles where auroras
occur) and the exosphere (where many satellites orbit).
Despite this distinction, the entire thermosphere warms as
altitude increases.
Although there is no distinct beginning or end to any of
the layers, the transition from one to another is known as a
“pause”. For example, the transition from troposphere to
stratosphere is called the tropopause. The stratopause divides
the stratosphere and mesosphere and the mesopause divides
the mesosphere and thermosphere. There is no pause after
the thermosphere because it blends into space as the
concentration of atmospheric molecules gets lower and lower.
Sketch and label:
http://ds9.ssl.berkeley.edu/LWS_GEMS/3/laye
rs.htm
 atmospheric layers (4)
 temperature
 ozone layer
Practice:
_____ In which level of the atmosphere does weather occur?
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
E. Exosphere
_____ Which level of the atmosphere is the densest?
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
E. Exosphere
_____ What best describes the density of the atmosphere?
A. It increases as you increase in altitude
B. It decreases as you increase in altitude
C. It maintains a constant level throughout the atmosphere
D. It shows fluctuations up and down as you move through
the layers of the atmosphere
E. It does not change
_____ What is the importance of the ozone layer?
A. It plays an important role in the greenhouse effect.
B. It reflects solar gamma reaction that would otherwise reach
Earth’s surface.
C. It acts as an insulator for the earth and helps to maintain a
livable temperature.
D. It absorbs incoming UV rays.
E. It reflects incoming heat back into space.
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UNEQUAL HEATING OF EARTH
Factor 1: Variation in Sun’s Angle
Because of Earth’s spherical shape, sunlight strikes
the earth at a perpendicular angle only at the equator. As
you move away from the equator, the sun’s rays hit the
earth at a more oblique angle. When the angle is more
oblique, the sunlight must travel a longer distance
through the atmosphere. This allows for a lot of energy
to be absorbed by the atmosphere, leaving little to hit
the earth. Near the equator, sunlight travels only a short
distance through the atmosphere, less energy is
absorbed, and more energy is left to hit the earth.
Practice:
_____ What region of the earth does the sun hit at the most direct
angle?
A. North Pole (90 N)
D. 30-60 S
B. South Pole (90 S)
E. Equator (0)
C. 30-60 N
_____ Which of the following is not true about the sun’s energy
heating the earth?
A. The sun’s rays hit the earth at different angles depending on
the latitude.
B. The sun’s rays are concentrated over a smaller surface area at
the equator than they are in higher latitudes.
C. The polar regions reflect more sunlight than the tropical
regions.
D. The sun’s rays are more strongly reflected in the lower latitude
regions.
E. The unequal heating helps to determine an area’s climate.
http://astro.unl.edu/naap/motion1/animations/seaso
ns_ecliptic.html
Factor 2: Angle of incidence
Air is heated much more at the equator, where the
sun’s rays strike directly, than at the poles, where
sunlight strikes at an angle and spreads out over a much
larger area. These differences in energy input help
explain why tropical regions near the equator are hot,
why polar regions are cold, and why temperate regions
in between generally have warm and cool temperatures.
The intense input of solar radiation in tropical
regions leads to greatly increased evaporation of
moisture from forests, grasslands, and bodies of water.
As a result, tropical regions normally receive more
precipitation than other areas of Earth.
Use the above website to manipulate the sun and Earth to determine the cause
of the seasons.
June marks Summer in the Northern hemisphere draw. Draw the
relationship of the sun and Earth during this time. (Shapes not to
scale). Draw North America, include the tilt of the axis of Earth
(you can use a line through the poles), draw a line to represent the
equator, shade the part of Earth that is in “darkness” and include
arrows to indicate solar radiation hitting Earth from the sun.
Sun
Factor 3: Albedo
We will discuss later
EARTH’S TILT AND SEASONS
The earth is tilted 23.5° on its axis. The North Pole is
always pointed toward the North Star. During the spring December marks Summer in the Northern hemisphere draw.
equinox (first day of spring), the equator (0° latitude) is
Draw the relationship of the sun and Earth during this time.
facing directly toward the sun. In this “neutral” position, (Shapes not to scale). Follow the same directions from above
the equator is getting the most direct sunlight and the
rest of the earth is getting indirect sunlight. (Reread the
Unequal Heating of Earth summary if necessary.) Six
months later, at the autumn equinox, the earth is in the
same position except on the opposite side of its
Sun
revolution around the sun.
During summer and winter, the northern hemisphere
is tilted either toward (summer) or away from (winter)
the sun. This means during our summer, our angle of
incidence is higher and therefore we receive more energy
per unit area and experience a higher average
temperature. The opposite is true for our winter when
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we are tilted away from the sun.
Because the earth is only tilted 23.5° and we are at
40° N, we never get the sun’s most direct rays. During
our summer, the direct rays shine on 23.5° N latitude,
the Tropic of Cancer. During our winter, the direct rays
shine on 23.5° S latitude, the Tropic of Capricorn. The
area between these two tropics (equatorial region) is
always receiving a lot of concentrated solar energy and
stays warm year round. But since the warmest area
shifts, so does the rain (formed when warm air rises,
cools, and releases water as precipitation). Areas just
north and south of the equator stay warm but may
experience dry seasons during their respective winters.
A common misconception is that the earth is
closer to the sun in the summer and farthest from the
sun in the winter. Actually, Earth’s perihelion
(peri=near, helios=sun) occurs around January 3.
Earth’s aphelion (apo=away) occurs around July 4. The
difference between these two distances is only about 5
million kilometers (about 3% of the distance to the sun),
not enough to affect temperature. Earth’s tilt and its
effect on the angle of incidence is the determining factor
when it comes to seasons.
Practice
_____The primary cause of Earth’s seasons is the
A. Constant tilt of Earth’s rotational axis with respect to the
plane of its orbit around the Sun
B. Changing distance of Earth from the Sun at different
times of the year
C. Periodic wobbling of Earth on its axis of rotation
D. Changing relative positions of Earth, its Moon and the
Sun
E. Periodic changes in solar energy output
_____ What latitude receives the most direct sunlight throughout
the year?
A. 90° N
B. 30°-60° N
C. 0°
D. 30°-60° S
E. 90° S
EARTH’S ROTATION AND THE CORIOLIS EFFECT
In the northern hemisphere, large air masses generally appear to curve clockwise and in the southern hemisphere, they
appear to curve counterclockwise. This curving pattern is a result of the earth’s rotation in an eastward direction as winds
move above the surface. The apparent curvature of object traveling long distances on Earth is known as the Coriolis effect.
On a global scale, this effect produces steady, reliable wind patterns, such as the trade winds and mid-latitude Westerlies.
Ocean currents also experience the Coriolis effect and curve clockwise in the northern hemisphere and counterclockwise in
the southern hemisphere.
Imagine you are in space looking down at the North Pole (the center of your field of view). As the earth spins on its axis,
the North Pole is moving much slower than the equator because it’s a much smaller area. In 24 hours a point near the North
or South Pole (Point A) will not travel nearly as far as a point near the equator (Point B).
An object (like a large mass of air or water) traveling from Point B to Point A will be moving faster than the middle
portion of the hemisphere and will end up to the right of Point A. The same object traveling from A to B will be moving
slower than Point B and will land behind Point B. Both examples show a clockwise (to the
right) curve according to the point of origination. The same effect is seen in the southern
hemisphere, with object appearing to curve counterclockwise (to the left) according to the
direction they came from.
Large masses of air, moving long distances, like Earth’s atmospheric convection cells
are influenced by the Coriolis effect. This is seen in the world’s prevailing winds. The six
major wind belts (formed by the six convection cells) all curve clockwise in the northern
hemisphere and counterclockwise in the southern hemisphere. The winds on either side of
the equator are the Northeast and Southeast trade winds. From 30°-60° are the Westerlies.
At the North and South Pole are the polar easterlies. Winds are always named for the
direction they come from.
4
Watch the following video about the Coriolis Effect:
https://www.youtube.com/watch?v=i2mec3vgeaI
If you threw a paper airplane North from Texas what is the
most likely place it would land:
A. California
B. Nebraska
C. Delaware
D. Mexico
Practice
_____ Which of the following statements about the Coriolis
Effect is incorrect?
A. The Coriolis effect causes object to be deflected to the
right in the northern hemisphere.
B. The Coriolis effect causes objects to be deflected
clockwise in the southern hemisphere.
C. Global winds are not affected by the Coriolis effect.
D. The Coriolis effect is caused by the rotation of the earth.
E. The different rotation speeds of Earth at different
latitudes causes the deflection of traveling objects.
An object moving from the Equator south would move to the
___________ (assuming you were facing South)
_____ The Coriolis effect and prevailing winds contribute to
the formation of gyres in the oceans. Which direction do
these gyres flow in the Northern Hemisphere?
Identify the hurricane of the hurricane pictures below
A. North to South
D. Counterclockwise
(Northern or Southern Hemisphere)
B. South to North
E. East to West
C. Clockwise
_____ A plane leaves the North Pole. Initially, it flies directly
south towards point B on the diagram. Which is the most
likely landing site for the plane if it maintains a straight path
to the south? A, B, C, or D?
5
ATMOSPHERIC CONVECTION CURRENTS
Four properties of air influence its movement around the world.
1. Density. Warm air is less dense so it rises. Cool air is denser so it sinks.
2. Water Vapor Capacity. Warm air can hold more water vapor than cold air. This helps explain why summer days in
Indiana are hot and humid and winter days are cold and dry. The maximum amount of water vapor that air can hold
is called its saturation point. The saturation point is higher for warm air because it can hold more water. Conversely,
the saturation point is lower for cool air because it can hold less water. As air cools, the saturation point lowers and
the air can’t hold any more water vapor. The water vapor will condense and leave the air as precipitation.
3. Adiabatic Cooling/Heating. As air rises, the pressure lowers. This allows molecules to move further apart (and
collide less), cooling the temperature of the air. When air sinks, the pressure rises, causing molecules to collide more
and the temperature to rise. This forced change in temperature because of change in pressure is called adiabatic
cooling or heating.
4. Latent Heat Release. When water evaporates (liquid to gas) a tiny amount of energy is stored. This energy is known
as latent heat. The latent heat will be released when the opposite process occurs and the water condenses into a liquid.
Whenever precipitation is forming and latent heat is being released, the air will warm and rise.
Because the earth is heated unevenly, some areas experience
the warm, less dense, wet, rising air and some areas experience
cool, denser, dry, sinking air. The warmest air is found near the
equator (in the intertropical convergence zone) where heat
from the sun is most direct. This solar energy evaporates ocean
water and transfers heat from the oceans to the atmosphere.
Once the air has cooled and released precipitation, it will sink
back down as cooler, drier air. This continuous cycle of rising
and falling air creates large convection currents of air around
the earth. Along with rising and falling air, air moves across the
surface of the earth from areas of high pressure to areas of low
pressure. This continual displacement and replacement of air
forms large convection cells.
Hadley cells are convection cells north and south of the equator. Polar cells are convection cells at the north and south
pole. In the area between (where we live) air circulates based on the Hadley and polar cells but does not form a strong
convection cell. This is partly why we experience a variety of different weather conditions, even during the same season.
Watch the video lectures to help you label the
diagram (you might have to Google as well):
https://www.youtube.com/watch?v=Ye45DGkqUkE
https://www.youtube.com/watch?v=8ixT7D3f8Qo
On the diagram to the left draw and label the
following:
- High and Low Pressure
- Hadley Cells (with arrows)
- Westerlies
- Easterlies
- Ferrel Cells (with arrows)
- Polar Cells (with arrows)
6
Practice
_____ What happens to air as it rises?
A. The pressure decreases and it expands in volume.
B. The pressure increases and it expands in volume.
C. The pressure decreases and it decreases in volume.
D. The pressure increases and it decreases in volume.
E. The pressure and volume remain constant.
_____ What is the overall direction of global air currents
at the equator?
A. Air rises at the equator.
B. Air sinks at the equator.
C. Air moves horizontally to the north at the equator.
D. Air moves horizontally to the south at the equator.
E. Air is relatively stable at the equator.
_____ What is the best explanation for the high amounts of
rain that occur at the equator?
A. This area experiences a high amount of wind, which leads to
storms and rain.
B. This area has a large amount of water, leading to more rain.
C. The warm air rises at the equator and condenses at a high
altitude, leading to rain.
D. The low pressure system that develops here causes warm air
to sink, leading to rain.
E. As the air rises, it becomes warmer, leading to more rain.
_____ What type of weather would you expect to find at the
intertropical convergence zone (ITCZ)?
A. Dry and warm weather
B. Dry and cool weather
C. Warm and rainy weather
D. Cool and rainy weather
E. Warm in the summer and cool in the wi
OCEAN CURRENTS
Along with unequal heating of the earth, atmospheric convection currents, the rotation of the earth and the Coriolis effect,
and Earth’s orbit around the sun on a tilted axis, Earth’s weather and climate are also influenced by the circulation of surface
and deep ocean waters.
Sunlight warms the ocean’s surface but does not penetrate deeply, so ocean water is warmest at the surface and becomes
colder with depth. Surface waters receiving more solar radiation at the equator are warmer than surface waters in temperate or
polar regions. Like air, warm water is less dense than cool water. This leads to a heavy layer of cold, salty, sinking water under
a lighter, warmer, less salty layer.
The high heat capacity of water allows it to absorb a lot of solar radiation and remain relatively stable in temperature. By
absorbing and releasing heat to the atmosphere, the oceans regulate Earth’s climate. Oceans also influence climate by moving
heat from place to place via surface circulation.
Large-scale ocean currents (gyres) are driven by temperature, prevailing winds, and gravity. Surface currents flow
horizontally great distances across the globe, curving according to the Coriolis effect and the location of continents. Equatorial
ocean currents carry warm water to cooler regions. Cool water currents carry water from high latitude regions or from deep in
the ocean. Surface currents like the Gulf Stream are rapid and powerful, bringing warm water from the Gulf of Mexico to
Europe, moderating the continent’s climate, which would otherwise be much colder.
Surface winds and heating also create vertical currents in the ocean. Upwelling, the upward movement of cold, deep water
toward the surface, occurs where horizontal currents diverge or flow away from one another. Cold, upwelled water is rich in
nutrients and generally high in productivity. Deep in the ocean, vertical currents create rising and falling convection cells, like
those in the air.
The worldwide current system in which warmer, fresher water moves along the surface and colder, saltier water moves
deep beneath the surface is known as thermohaline circulation. Scientists hypothesize that melting of Greenland’s ice sheet,
because of climate change, may make North Atlantic waters less salty and less likely to sink. This change could trigger a
shutdown of thermohaline circulation, causing temperate areas like Europe to rapidly cool.
7
Practice
_____ What is one major role that these gyres play
in global climate?
A. Currents redistribute heat from the North to the
South
B. Currents redistribute heat from the Equator to
Northern latitudes
C. Drive global wind patterns in the Northern
hemisphere
D. Contribute to the Coriolis effect
E. Currents redistribute tropical moisture
8
El Niño Southern Oscillation
Another interaction between ocean currents and the
atmosphere that influences climate is the El Niño-Southern
Oscillation (ENSO), a naturally occurring shift in atmospheric
pressure, sea surface temperature, and ocean circulation in the
tropical Pacific Ocean. Under normal conditions, Northeast
and Southeast trade winds blow along the equator, from a
region of high pressure in the eastern Pacific to one of low
pressure in the western Pacific, forming a large-scale convection
loop in the atmosphere. The winds push surface waters
westward, causing warm surface water to “pile up” in the
western Pacific. As a result, water near Indonesia can be up to
8C warmer than water near South America. The westwardmoving surface waters are replaced by cold water rising up
from the deep in a nutrient-rich upwelling along the coast of
Peru and Ecuador.
El Niño conditions are triggered when air pressure decreases
in the eastern Pacific and increases in the western Pacific,
weakening the equatorial winds and allowing warm water to
flow eastward. This suppresses upwelling along the Pacific
coast of the Americas, shutting down the delivery of nutrients
that support marine life and fisheries. El Niño events alter
weather patterns around the world, creating rainstorms and
floods in areas that are generally dry (like southern California)
and causing drought and fire in regions that are typically moist
(like southern Africa and Southeast Asia).
Practice
_____ What is a positive effect of upwelling?
A. Creates an area of high precipitation
B. Creates an area of high nutrient levels along the coast
C. Creates an area of high nutrients in the center of the ocean
basin
D. Creates an area of low precipitation
E. Brings warm water to the surface of the ocean
El Nino tutorial video:
https://www.youtube.com/watch?v=WPA-KpldDVc
Notes:
_____ Which of the following is true about ENSO?
I. Upwelling is suppressed off the coast of South
America
II. This phenomenon is human caused and related to
global warming
III. The tradewinds weaken, allowing warm water to
move eastward
A. I only
B. II only
C. III only
D. I and III
E. I, II, and III
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THE RAIN SHADOW EFFECT
Many of the processes that affect weather and climate
occur on a global scale, but local features, like topography (the
shape of the land) also play a role. Climbing in elevation causes
a much more rapid change in climate than moving the same
distance toward the poles. There is a distinct change in
vegetation along mountain slopes that corresponds with this
altitude-induced climate change.
When large masses of air encounter mountain ranges, the
air is forced upwards. This rising air experiences the same
changes as rising air at the equator: it cools, expands, releases
water vapor as precipitation, and decreases in pressure. All the
rain on this (windward) side of the mountain range often leads
to lush vegetation. By the time the air flows over the mountain
and back down the other side, it has released most of its water
and is very dry. The warm, dry, arid side is called the leeward
side and is known as the rain shadow region.
This rain shadow effect can be seen in the Sierra Nevada
range in the Western United States. Look at the graph below.
Notice how precipitation rises on the windward side of each
mountain range and falls on the leeward side of each mountain
range.
Practice
_____ The rain shadow effect can have a large effect on
local climate. When the rain shadow effect is occurring,
which side of the mountain tends to receive more rain?
A. Windward side
B. Leeward side
C. Top of the mountain
D. Foot of the mountain
E. Side of the mountain that does not face the ocean
_____ Which of the following statements explains the
rain shadow effect?
A. Mountains force air to rise; air cools and releases
moisture as it rises.
B. The atmosphere gets denser as elevation increases,
causing snow to fall.
C. Temperatures are higher on one side of a mountain
than the other.
D. Wind patterns cause precipitation
E. Lush vegetation on one side of a mountain causes it to
rain more on this side
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