Chapter 3 Introduction to the Atmosphere

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Chapter 3 Introduction to the Atmosphere

• Physical Geography
• A Landscape Appreciation, 9/e
• Animation Edition

Victoria Alapo, Instructor Geog 1150
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Introduction to the Atmosphere

• Composition of the Atmosphere
• Vertical Structure of the Atmosphere
• The Ozone Problem
• Weather and Climate
• The Coriolis Effect

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Composition of the Atmosphere

• Gases
• Particulates

• The gases that make up air.
• Permanent and variable gases, pg 56.
• some of these are greenhouse gases.

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Atmospheric Particulates (Aerosols)

• Tiny solid and liquid particles (non-gaseous
  particles)
• - Effects on weather and climate

• Sources include (natural human)
• Ice, pollen, volcanic ash, salt sprayed by
  oceans, wind-blown soil, meteor debris, smoke
  from wild-fires.
• Emissions (auto factories), soot, etc
• They affect weather and climate in 2 ways
• - they are hygroscopic, i.e. they attract water,
  so water molecules form around them.
• they can decrease the amt of solar energy
  reaching Earth, like ash during a volcanic
  eruption (see Pompei pictures).

Fig. 3-4, pg 57
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Vertical Structure of the Atmosphere

• Temperature
• Pressure
• Composition

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Thermal Layers of the Atmosphere

• Know how temperatures increase or decrease in
  each layer. Pg 58
• The top of each layer ends with a pause.

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• Troposphere
• Our weather occurs here

• Fig. 3-6a and b pg 59

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Atmospheric Pressure

• Pressure
• Decreases with increasing altitude, pg 60

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• Table 3-2 Atmospheric Pressure at Various
  Altitudes (Expressed as a percentage of sea-level
  pressure)

• Air pressure decreases with increasing altitude
  but not at a constant rate

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Atmospheric Composition

• Homosphere
• Zone of uniform distribution of gases (think pie
  graph on first slide)
• Heterosphere
• - Zone of layers
• - Gases are in layers according to molecular
  weights

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• Special layers
• Ozonosphere the ozone layer, 9 to 30 miles up.
  Although not only ozone is found here. Pg 61.
• Ionosphere layer of electrically charged
  molecules atoms (ions). 40 to 250 miles up.
  Impt for radio waves.

Fig. 3-10 Aurora Borealis in the Ionosphere

• Fig. 3-11

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Vertical Structure of the Atmosphere
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The Ozone Problem

• Natural Atmospheric Ozone
• Destruction of Ozone by Chlorofluorocarbons
  (CFCs)
• The Antarctic Ozone Hole, pg 64

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Natural Ozone
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Ozone Destruction by CFCs
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Weather and Climate

• Weather describes temporary atmospheric
  conditions e.g. current temperature,
  precipitation, wind speed, etc. for a short
  period of time.
• On the other hand, Climate is the aggregate of
  weather conditions, usually over a long period of
  at least 30 years.
• So weather climate are related but not
  synonymous.
• Elements of Weather and Climate
• Controls of Weather and Climate

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Elements of Weather and Climate
Elements used for measuring weather climate
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Controls of Weather and Climate

• The reasons why weather climate vary all over
  earth.
• Although each is discussed separately, theres a
  lot of overlap in real life.
• See next slides.

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Latitude and Available Solar Energy
Long vs. short rays
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Distribution of Land Water

• Oceans heat cool more slowly than landmasses.
• Maritime (coastal areas) experience milder
  temperatures than continental areas, in both
  summer winter.
• E.g. Seattle, WA vs. Fargo, ND.

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General Circulation of the Atmosphere
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General Circulation of the Oceans
Transfers heat and cool water around the globe,
and affects neighboring continents. E.g. The
coast of Namibia (Africa) is cold, in spite of
its latitude.
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Elevation (Altitude)
The higher you go, the cooler it becomes, and
vice-versa (at least in the troposphere).
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Topographic Barriers
See caption, pg 69. Differences on the same
island!
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Storms
They create specialized weather conditions, so
they are regarded as a control.
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• The Coriolis Effect
• Because of the Earths rotation, any object
  moving freely tends to be deflected to the right
  in the Northern Hemisphere, to the left in the
  Southern Hemisphere
• Significance
• Winds
• Ocean currents
• Airplanes, missiles, and even ships, pg 70-71.
• Animation

• Fig. 3-23, showing planned route of wind, and
  actual movement.

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• Coriolis Effect (Summary)
• Definition
• An apparent deflection of any freely moving
  object from its expected (straight) path
• Four basic points to note
• Apparent deflection is to the right in the
  Northern Hemisphere, to the left in the Southern
  Hemisphere.
• Apparent deflection is greatest at the poles,
  progressively less toward the equator, where
  there is zero deflection.
• The effect is proportional to the speed of the
  object, so a fast-moving object is deflected more
  than a slower one.
• The effect influences the direction of movement,
  not the speed.
• It seems to not have an effect on toilet bowls,
  sinks, etc (pg 72).