The Atmosphere

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The Atmosphere
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BIG Idea

• The composition, structure, and properties of
  Earths atmosphere form the basis of Earths
  weather and climate.

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Who studies atmospheric conditions?

• Meteorologiststhats who!

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• How would you describe the difference between
  WEATHER and CLIMATE?

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I. Characteristics of the Atmosphere

• Weather day-to-day changes in atmospheric
  conditions.
• These conditions include
• Temperature
• Air movements
• Moisture content

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• Climate general weather conditions averaged
  over many (about 30) years

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A. Composition of the Atmosphere

• 78 Nitrogen
• 21 Oxygen
• 0.9 Argon
• 0.1 Other

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• Ozone protects us
• from harmful UV (ultraviolet)
  rays
• Damaged by CFCs
• (poisons in ACs
• and refrigerators)

Ozzy Ozone
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• Have you noticed the weather today?
• How would you describe it?

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B. Properties of the Atmosphere

• Temperature
• Air Pressure
• Humidity

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1. Temperature

• measure of the average kinetic
  energy of particles in a material
• more energy moving faster higher temperature
• measured with a thermometer

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2. Atmospheric (Air) Pressure

• the ratio of the force of the air to the area of
  the surface on which it presses
• the weight of the atmosphere pressing down on
  Earths surface

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BAROMETER

• an instrument that measures atmospheric pressure

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a. Mercurial Barometer
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b. Aneroid Barometer

• Aneroid without liquid

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3. Humidity

• the amount of water vapor in the atmosphere at a
  given location on Earths surface

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C. Layers of the Atmosphere

• Based on temperature differences, scientists
  identify four layers of Earths atmosphere
• Each layer is separated by a pause

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• Visualizing the Layers of the Atmosphere

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1. Troposphere all weather occurs here

• Layer closest to Earths surface

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2. Stratosphere where most of the ozone is
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3. Mesosphere coldest layer (-90C )4.
Thermosphere hottest layer (over 2000C)
nitrogen and oxygen atoms absorb solar energy
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• Components of the Atmosphere - Quiz

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II. Solar Energy

• A. Radiation all forms of energy that travel
  through space as waves

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What happens to solar energy that reaches Earths
surface?
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1. reflected (sent in a new direction), or
2. absorbed

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• Why does the inside of a closed parked car heat
  up, while the windows stay cool?

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B. Greenhouse Effect atmosphere traps (long)
infrared rays

• The Suns energy
• is trapped inside.

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• What are the greenhouse gases that trap heat
  within our atmosphere?

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• Water vapor
• Carbon dioxide
• produced by humans
• burning of fossil fuels (oil, gas, coal)

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C. Heat Energy Transfer
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1. Convection transfer of heat energy in gases or
   liquids due to density differences.

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• 2. Conduction transfer of heat energy through
  matter from particle to particle
  most effective in
  solids.

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• 3. Radiation waves that directly transport
  energy through space brings
  HEAT to our planet.

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III. Winds

• Created by uneven heat distribution at Earths
  surface
• The amount of energy reaching any given point on
  Earths surface is controlled by the angle of
  sunlight striking the surface

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• What causes the amount of energy to vary?
• Hint

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• Our tilt, and the seasons!
• Where on Earth will you receive more of the suns
  energy per unit area?
• Where will you receive less?

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• The Coriolis Effect Earths rotation causes
  winds to deflect (curve) to the right in the
  Northern Hemisphere and to the left in the
  Southern Hemisphere.
• Same with water

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A. Global Winds

• Winds are named according to the direction FROM
  which they flow!
• 1. Trade Winds winds in both hemispheres
  flowing towards the equator
• between 30 (N and S) and 0 latitude

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• Doldrums weak and unpredictable air mix, 5 N
  and S of the equator
• winds CONVERGE here to form an area of LOW
  pressure
• b. Horse Latitudes very weak air movement 30-
  35 N and S

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• 2. Westerlies between 30 and 60 N and S.
• 3. Polar Easterlies weak winds at 60 N and S
  that flow away from the poles.

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TICKET ITEM!!

• Why does warm air rise from the equator, and cold
  air sink at the poles?

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• 4. Jet Stream bands of high- speed
  high-altitude westerly winds.

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B. Local Winds / Breezes
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1. Sea Breeze in the daytime, winds from cooler
water replace warm rising land air
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2. Land Breeze at night, winds from cooler land
replace warm air over the water

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3. Valley Breeze in the day warm air rises UP
the valley

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4. Mountain Breeze at night, cool air sinks
DOWN the mountain

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What causes weather?

• uneven heating by the Sun due to Earths axis
  tilt
• energy transfer between Earths surface and the
  atmosphere