UNIT 5: Atmosphere

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UNIT 5 Atmosphere WeatherChapter 17
Atmosphere

• C/S 17.1 The Atmosphere in Balance
• C/S 17.2 Heat and the Atmosphere
• C/S 17.3 Local Temperature Variations
• C/S 17.4 Human Impact on the Atmosphere

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C/S 17.1 The Atmosphere in Balance

• The atmosphere is like a space suit that has
  changed greatly with time (evolved)
• The past atmosphere
• Methane Ammonia (4 Bill. Yrs. Ago by volcanoes)
• Sunlight gtnitrogen, hydrogen carbon dioxide
• Sunlight broke down water vapor to ozone or O3
• Blue-green algae produce oxygen (o2)
• 600 mill. years ago O2 CO2 stabilized

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C/S 17.1 The Atmosphere in Balance (cont)

• The present Atmosphere
• Gases The two main gases are Nitrogen (N2)
  Oxygen (O2). Other gases are Carbon Dioxide
  (CO2), Water Vapor (H2O) Argon (Ar)
• The atmosphere is stable because it has an
  efficient recycling system.
• Nitrogen living organisms need it to make
  protein bacteria in soil release it for plants
• Oxygen essential for respiration combustion or
  burning of fuels
• Carbon Dioxide raw material used by plants
  during photosynthesis, returned by respiration
  "Greenhouse Effect"

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C/S 17.2 Heat and the Atmosphere

• How Heat Energy Moves
• Three ways Conduction, Convection and Radiation
• Conduction-Transfer of heat energy through
  collisions of the atoms or molecules of a
  substance.
• Convection-Transfer of heat energy in a liquid or
  gas through the motion of the liquid or gas
  caused by differences in densities.
• Radiation-Transfer of energy through space in the
  form of visible light, ultraviolet light and
  other types of electromagnetic waves.
• Structure of the Atmosphere
• Troposphere
• Lowest layer, earth's weather
• height 6 to 17 km
• Convection currents w/n Troposphere (hot air
  rises)
• Temperature Drops 6.5( C/km
• Tropopause-boundary

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C/S 17.2 Heat and the Atmosphere (cont)

• B. Structure of the Atmosphere (cont)
• Stratosphere
• Stratosphere to about -60( C50 km
• Jet Stream-eastward winds 320 km/hr
• Ozone (O3) combined w/ O2 in lightning
• 16-60 km ozonosphere
• absorbs UV light and release heat
• Stratopause (18( C) boundary

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C/S 17.2 Heat and the Atmosphere (cont)

• Structure of the Atmosphere (cont)
• Mesosphere Thermosphere
• 50-90 km Mesosphere, above 90 km Thermosphere
• Meteoroids burn up (shooting stars)
• Ionosphere- lower part of the thermosphere
• 90-500 km
• Electrically charged atoms-ions
• Reflect radio waves
• Satellites- weather, communication, and defense
• Insolation and the Atmosphere
• Insolation-Incoming Solar radiation
• The energy transfer from the earth's surface is
  one of the major causes of weather in the
  atmosphere.
• The accumulation of Carbon Dioxide and Water
  Vapor absorb most of the infrared radiation

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C/S 17.3 Local Temperature Variations

• Intensity of Insolation
• Time of day-Most direct sun rays at noon
• Latitude-Equator receives the most direct sun
  rays. Locations at the poles can receive no
  daylight or daylight all day.
• Time of Year-In the summer the Northern
  Hemisphere gets direct sunshine and the Southern
  Hemisphere is indirect. The opposite happens in
  winter. (remember proximity of Sun)
• Clouds-The intensity of clouds affects the amount
  of insolation that reaches the earth.

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C/S 17.3 Local Temperature Variations (cont)

• Heating of Water and Land
• Water and Land cool at different rates
• Specific Heat-The amount of heat needed to raise
  1 gram of a substance by 1 oC. The specific heat
  of water is almost 3 times that of land.
• Isotherms-Lines that connect places with the same
  temperature.
• Seasonal changes

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C/S 17.4 Human Impact on the Atmosphere

• Common Air Pollutants
• Air Pollutant-any airborne gas or particle that
  occurs at a concentration capable of harming
  humans or the environment.
• Clean Air Act of 1970-Six key pollutants Carbon
  Monoxide, Nitrogen Dioxide, Sulfur Dioxide,
  Particulate Matter, Lead and Ozone.
• Acid Rain
• Forms when sulfur dioxide and nitrogen oxides mix
  with water.
• Acidity is measured using the pH scale. Ranges
  from 0-14. 7 is neutral. Acid rain is around 5.

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C/S 17.4 Human Impact on the Atmosphere (cont)

• Smog
• Photochemical smog is a brownish haze that forms
  in air polluted with nitrogen oxides and
  hydrocarbons from automobile exhaust.
• Temperature Inversion-An increase in temperature
  with an increase in altitude occurs when a layer
  of cold air is trapped beneath a layer of warm
  air.
• Ozone Depletion
• Caused by Chlorofluorocarbons (CFCs)
• Loss of ozone increases exposure to harmful
  ultraviolet radiation.

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C/S 17.4 Human Impact on the Atmosphere (cont)

• Global Warming
• Average temperatures have increased 1 oC since
  1880.
• Caused by the burning of fossil fuels and global
  deforestation, which raises the amount of CO2 in
  the atmosphere.
• Creates changes in climate, a rise in sea level
  and increased drought.
• An Inconvenient Truth - Science