Chapter 15

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Chapter 15 The Atmosphere

• Atmosphere A mixture of gases composed of 78
  nitrogen and 21 oxygen.
• Gravity holds the gases close to the Earth making
  it thicker with higher pressure near the surface
  and thinner with lower pressure at higher
  altitudes.
• The Layers of the Atmosphere
• Troposphere the lowest, densest and closest
  layer to the surface of the Earth containing 90
  of the mass of the atmosphere.
• Stratosphere the gases in this layer are thin
  and do not mix. Thin with very little moisture.
• Mesosphere the coldest layer characterized with
  a decrease of temperature with increasing
  altitude (inverse relationship). This is the
  middle layer but also is one of the highest
  layers.
• Thermosphere one of the highest layers
  containing too few air molecules to successfully
  transfer any thermal energy. Temperatures may
  reach 1000C.
• Ionosphere composed of the upper mesosphere and
  lower thermosphere where nitrogen oxygen atoms
  absorb harmful solar radiation. These gas
  particles become electrically charged (ionized)
  and form the auroras when energized by solar
  particles. This layer also reflects radio waves
  back to the surface.

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• Atmospheric Heating
• Energy from the sun reaches the Earths surface
  in the form of electromagnetic waves called
  radiation. Only about two billionths
  (2/1,000,000,000,000) of the suns energy ever
  reaches the Earths surface and half of that get
  absorbed by the water and land (50).
• Thermal Conduction The transfer thermal energy
  through a conductive material. Similar to
  cooking. Heat is transferred from the flame to
  the pot to the food.
• Convection The transfer of heat by the
  molecules of a liquid or a gas. The movement
  created when warm air rises and cold air sinks.

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• Greenhouse Effect The warming of the surface
  and lower atmosphere caused by water vapor,
  carbon dioxide, sulfur dioxide, nitric oxide
  (greenhouse gases) that absorb radiation and
  transfer the thermal energy to the surroundings.
• Global Warming The unnatural, gradual average
  global temperature increase due to an increased
  concentration of greenhouse gases.
• Global Local Winds
• Wind The movement of air caused by differences
  in air pressure. The greater the pressure
  differential, the stronger the wind. Differences
  in air pressure are caused by the unequal heating
  of the Earths surface with warm air rising at
  the Equator and cooler air sinking at the Poles.
• Convection (Hadley) Cells Large, circular
  patterns that the air travels in, separated by
  high and low pressure belts located about every
  30 latitude.
• Coriolis Effect The curving of the Earths
  winds and ocean currents caused by the Earths
  rotation.

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• Global Winds
• Polar Easterlies Winds that blow from the poles
  to 60 latitude.
• Westerlies The flow of air to the poles from
  the west to the east. This is the opposite of the
  Trade Winds and blow from 30 to 60 latitude.
• Trade Winds Winds that blow from 30 south
  latitude to 30 south latitude. Named by sailor
  who traveled from Europe to the Americas.
• Doldrums Located at the Equator where the Trade
  Winds meet and rise creating a very calm center
  of low pressure.
• Horse Latitudes A region located at 30
  latitude where the air sinks creating a high
  pressure, windless area. Many of the worlds
  deserts are located here.
• Jet Stream A narrow band of high altitude, high
  speed winds that blow up to 400 km./hr. (240
  m.p.h.) in the upper troposphere and lower
  stratosphere.

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• Local Winds Winds that move air short distances
  and can blow from any direction. Can be created
  by a shoreline, mountain range or even a forest
  fire.
• Mountain and Valley breezes Caused by
  differences in temperature created by changes in
  elevation. Valley breeze by day, mountain breeze
  by night. Breezes and winds are named by where
  they blow from.
• Air Pollution The contamination of the air by
  pollutants from human and natural sources. Can
  cause coughing, headaches and lung cancers.
• Primary Pollutants put directly from their
  source directly into the air. Car exhaust is the
  1 human primary pollutant.
• Secondary Pollutants A primary pollutant that
  reacts with other pollutants to create a new
  pollutant such as ozone and smog.
• Indoor air pollution is the result of the use of
  cleaners, heaters, dirty ductwork, chemicals from
  carpet, etc. Can be reduced with a proper
  ventilation system that mixes household air with
  outdoor air.

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• Acid Precipitation precipitation that contains
  acids from air pollution.
• Acidification Acid precipitation changing
  the acidity of the water and soil causing harmful
  effects.
• Acid Shock A rapid change of the acidity
  of a body of water killing fish and damaging eggs
  of fish and amphibians. Most harmful in our area
  with the spring thaw.
• Ozone Hole Harmful effects of chemicals called
  CFCs (chlorofluorocarbons) that are breaking
  down the ozone (O3) into oxygen (O2) allowing
  harmful ultraviolet (UV) radiation to reach the
  Earths surface.
• Cleaning Up Air Pollution
• Allowance Trading System Limits the amount
  of pollutants that a company can release.
• Hybrid Cars Uses both gasoline electric
  power.
• Scrubbers Devices that remove some
  pollutants before they are released into the air.
  Usually mounted on the tops of smokestacks.
• Cleaner fuels, catalytic converters, more
  efficient auto engines, etc.