17.1 Atmosphere Characteristics

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17.1 Atmosphere Characteristics

• Weather is constantly changing, and it refers to
  the state of the atmosphere at any given time and
  place.
• Climate, however, is based on observations of
  weather that have been collected over many years.
  Climate helps describe a place or region.

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Volume of Clean, Dry Air
What is the most abundant gas in our
atmosphere? What is the second most common gas?
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17.1 Atmosphere Characteristics
? Variable Components

• Water vapor is the source of all clouds and
  precipitation
• carbon dioxide, water vapor absorbs heat given
  off by Earth. It also absorbs some solar energy.

• Ozone is a form of oxygen that combines three
  oxygen atoms into each molecule (O3).

• ozone filters UV radiation in the stratosphere
  allowing life to exist as we know it,
• In troposphere ozone causes smog

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Primary Pollutants
What is a primary pollutant?
What is responsible for the majority of the
primary pollutants?
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17.1 Atmosphere Characteristics
? Pressure Changes affect temprature

• Atmospheric pressure is simply the weight of the
  air above.
• An increase in altitude decrease in pressure
• Decreases in pressure decrease in temperature

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Atmospheric Pressure vs. Altitude
Why does the atmosphere thin (become less
dense) with altitude? What affect does this
have on temperature?
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17.1 Atmosphere Characteristics
? Temperature Changes
Why is the Atmosphere Divided into Layers?
The atmosphere is divided vertically into four
layers based on temperature change.
troposphere bottom layer of the atmosphere
where temperature decreases with an increase in
altitude. Decreased pressure decreased temp
stratosphere layer on top of troposphere
temperature gradual increase because of O3
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Snowy Mountaintops Contrast with Warmer Snow-Free
Lowlands
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17.1 Atmosphere Characteristics
? Temperature Changes
mesosphere the layer above the stratosphere
and is characterized by decreasing temperatures
with height, contains no O3
thermosphere the layer above the mesosphere
and is characterized by increasing temperatures
due to the absorption of very short-wave solar
energy, atoms absorb max energy
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Thermal Structure of the Atmosphere
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17.1 Atmosphere Characteristics
? Earths Motions
rotation day and night revolution seasons
? Why do we have seasons?
Seasonal changes occur because of earths
revolution around the sun and Earths axis is
tilted to 23.5O
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Tilt of Earths Axis
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17.1 Atmosphere Characteristics
? Solstices and Equinoxes
summer solstice occurs on June 21 or 22 in the
Northern Hemisphere and is the official first
day of summer.
winter solstice occurs on December 21 or 22 in
the Northern Hemisphere and is the official
first day of winter.
During our winter solstice what season is it in
Australia?
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17.1 Atmosphere Characteristics
? Solstices and Equinoxes
autumnal equinox (Fall) occurs on September 22
or 23 in the Northern Hemisphere.
spring equinox (vernal) occurs on March 21 or
22 in the Northern Hemisphere.
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17.1 Atmosphere Characteristics

• is determined by Earths position in orbit. Think
  of the Arctic and Antarctic circle.
• http//esminfo.prenhall.com/science/geoanimations/
  animations/01_EarthSun_E2.html

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Solstices and Equinoxes
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17.2 Heating the Atmosphere
? Heat energy transferred from one object to
another because of a difference in the objects
temperature.
? Temperature a measure of the average kinetic
energy a substance, hot more kinetic energy, cold
less kinetic energy
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17.2 Heating the Atmosphere
What are the three mechanisms of energy transfer
as heat?
1. Conduction transfer of heat through solids
What are insulators? What are conductors?
2. Convection transfer of heat through fluids
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17.2 Heating the Atmosphere
3. Radiation transfer of energy (heat) through
space by electromagnetic waves, can travel
through the vacuum of space others can not
How does wavelength Relate to radiant
temperature?
6000Co11000Fo
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Energy Transfer as Heat
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17.2 Heating the Atmosphere
Electromagnetic Waves everything that has heat
emits these waves. Energy emitted by the sun are
part of the electromagnetic spectrum
Are good absorbers also good emitters of radiant
energy?
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Visible Light Consists of an Array of Colors
Why can you see the spectrum of electromagnetic
waves?
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Solar Radiation
What Happens to Solar Radiation?
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17.2 Heating the Atmosphere
Reflection when light bounces off an object,
with same intensity as incident radiation.
Scattering when light bounces off an object
producing a larger number of weaker rays that
travel in different directions.
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17.2 Heating the Atmosphere
? Absorption
50 percent of the solar energy that strikes
the top of the atmosphere reaches Earths surface
and is absorbed.
greenhouse effect heating of Earths surface
and atmosphere from solar radiation being
absorbed and emitted by the atmosphere, two main
gasses involved water vapor and carbon dioxide.
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• Global warming (climate change) the Green House
  Effect sped up by human activity

What is the Green House Effect? What are the main
gases that cause the effect?
What are the main greenhouse gases in troposphere
causing global warming?
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17.3 Temperature Controls
1. Land (low specific heat capacity) heats more
rapidly and to higher temperatures, also cools
more rapidly and to lower temperatures. Deserts
cold at night hot during day 2. Water (high
specific heat capacity) heats up slowly and cools
down slowly
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Mean Monthly Temperatures for Vancouver and
Winnipeg
Which is close to the ocean? What is the
effect? Which is furthest from the ocean? What
is the effect?
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17.3 Temperature Controls
3. geographic setting
How does geographic position influence these two
cities?
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17.3 Temperature Controls
4. altitude
How does altitude influence temperature?
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17.3 Temperature Controls
5. Cloud cover high albedo therefore reflect back
to space a significant portion of suns energy
Albedo is the fraction of total radiation that
is reflected by any surface.
How does cloud albedo affect these two pictures?
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17.3 Temperature Controls
? Isotherms lines on a weather map that connect
points of the same temperature
What do you notice about the isotherms in the
north compared to the south?