Layers of the Atmosphere

• The atmosphere is the blanket of air that surrounds the planet
• Composition of Earth's atmosphere

  • Nitrogen (78%)
  • Oxygen (21%)
  • Argon (1%)
  • Trace amounts of greenhouse gases, neon, helium, methane, krypton, hydrogen, nitrous oxide, xenon, ozone, carbon monoxide, ammonia
• Earth's atmosphere

  • Surrounds our planet
  • Keeps us warm
  • Provides us oxygen to breathe
  • Where our weather happens
• Layers of Earth's atmosphere

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere
• Troposphere


  The layer closest to the Earth's surface where weather happens
• Troposphere

  • 8-14 kilometers thick
  • Contains most of the water vapor
  • Air motion is determined by properties of the surface
  • Aircraft flying in this region may experience turbulence8-
• Stratosphere


  The layer where ozone is found
• Stratosphere

  • Extends to about 50 km from Earth's surface
  • Temperature increases with height due to absorption of UV radiation from the sun
  • Temperatures highest over summer pole, lowest over winter pole
  • Ozone protects us from UV radiation and health damage
• Mesosphere


  The middle layer
• Mesosphere

  • 50-80 km above Earth's surface
  • Temperature decreases with height
  • Meteors spend time in this layer, causing friction and heat
  • Air is very thin and cold
• Thermosphere


  The layer where temperature increases again with elevation
• Thermosphere

  • 80-110 km above Earth
  • High temperatures caused by absorption of UV and X-Ray radiation from the sun
  • Space shuttles fly in this region
  • Auroras are found here
  • Ionosphere is also located in this region, reflecting and absorbing radio waves
• Exosphere


  The upper limit of Earth's atmosphere
• Exosphere

  • 500-1000 km from Earth
  • Satellites are placed in this region
  • Atmosphere becomes very thin, atoms and molecules move out into space
  • Where Earth's atmosphere merges with space
• The sun is the source of energy for Earth, emitting radiation that passes through the atmosphere and reaches the planet
• Radiation from the sun


  Warms the Earth's surface
• Warmth from the Earth's surface

  Travels back into the atmosphere
• The farther removed from the Earth's surface the air moves, the less heat there is to absorb
• Some of the thermal radiation from the sun is absorbed by gases in the atmosphere
• Exosphere


  The layer of the atmosphere that extends from 300 km to 600 km from Earth's surface, where the atmosphere becomes very thin and atoms and molecules move out into space
• Thermosphere


  The layer of the atmosphere that extends from 90 km to 300 km, where space shuttles fly and auroras are found
• Mesosphere


  The layer of the atmosphere that extends from 50 km to 90 km, where meteors burn up
• Stratosphere


  The layer of the atmosphere that extends from 16 km to 50 km, where the ozone layer is found
• Troposphere


  The layer of the atmosphere that extends from 0 km to 16 km, where all weather occurs
• The Sun is the source of energy for the Earth, emitting rays (radiation) that warm the planet
• How the atmosphere warms the Earth

  1. Radiation from the Sun warms the Earth's surface

  2. Warmth from the Earth travels back to the atmosphere

  3. The air is warmed by heat given off by the Earth

  4. The farther removed from the surface the air moves, the less heat there is to absorb
• Greenhouse gases trap heat radiated from the Earth's surface, causing the greenhouse effect and global warming
• Greenhouse gases

  • Water vapor
  • Greenhouse gases
  • Inhalation general anesthetic
  • Methane
• Deforestation increases the amount of carbon dioxide in the atmosphere by reducing photosynthesis
• What flies in the stratosphere?

  Aircrafts or commercial jets