Atmosphere

• Atmosphere


  Blanket of air (mixture of gases) surrounding the Earth
• The Earth is surrounded by a blanket of air (mixture of gases) in which we call the atmosphere
• We cannot see this atmosphere but can only feel its presence
• The atmosphere is dynamic with many activities going on in the air above us
• The layer of air is thin compared to the Earth's size but its importance is enormous
• Main gases in the atmosphere

  • Nitrogen (N2)
  • Oxygen (O2)
  • Argon (Ar)
• Nitrogen and oxygen


  Active components involved in biogeochemical cycles
• Argon


  Inactive component not involved in biogeochemical cycles
• Water vapor


  Gaseous form of water, amount varies depending on atmospheric conditions
• Nitrogen, oxygen, and argon gases comprise about 99.97% of the Earth's atmosphere
• The rest of the atmosphere is composed of varying amounts of water vapor, carbon dioxide (CO2) and traces of inert gases
• Carbon dioxide (CO2)


  Small amount (0.03%) but equally important to life on Earth, continuously cycled through photosynthesis and respiration
• Aerosols


  Dusts, smoke, salt crystals, and tiny solid or liquid particles suspended and distributed in the atmosphere
• Aerosols


  • Act as surfaces on which water vapor can condense to form clouds or fog
  • Absorb, reflect, and scatter incoming heat from the sun
  • Contribute to the different hues of red and orange during sunrise and sunset
• Temperature decreases as altitude increases in the troposphere
• Troposphere


  Lowermost layer of the atmosphere, where most weather phenomena occur, and most clouds are found
• Tropopause


  Outer boundary of the troposphere
• Stratosphere


  Layer above the troposphere, with a layer-like structure, containing the ozone layer
• Stratosphere

  • Ozone layer absorbs ultraviolet radiation, resulting in heating of the stratosphere
  • Commercial passenger jets fly in the lower region of the stratosphere for a smoother ride
  • Jet stream flows near the border between the stratosphere and troposphere
• Mesosphere


  Middle layer of the atmosphere, where meteors burn up, and the coldest temperatures occur at the mesopause
• Thermosphere


  Upper layer of the atmosphere, where auroras occur, and many satellites orbit
• Thermosphere


  • High-energy X-rays and UV radiation from the Sun are absorbed, causing the temperature to rise to more than 1000°C
  • Despite the high temperatures, the air is so thin that it would still feel freezing cold
• Ionosphere


  Overlaps the mesosphere and thermosphere, an abundant layer of electrons and ionized atoms and molecules
• Ionosphere


  • D Layer absorbs the most energetic radiation (hard x-rays)
  • E Layer absorbs soft x-rays
  • F Layer absorbs extreme ultraviolet radiation (EUV)
  • Reflects standard AM radio waves back to Earth
• Atmosphere


  Blanket of air (mixture of gases) surrounding the Earth
• The Earth is surrounded by a blanket of air (mixture of gases) in which we call the atmosphere
• We cannot see this atmosphere but can only feel its presence
• The atmosphere is dynamic with many activities going on in the air above us
• The layer of air is thin compared to the Earth's size but its importance is enormous
• Main gases in the atmosphere

  • Nitrogen (N2)
  • Oxygen (O2)
  • Argon (Ar)
• Nitrogen and oxygen


  Active components involved in biogeochemical cycles
• Argon


  Inactive component not involved in biogeochemical cycles
• Water vapor


  Gaseous form of water, amount varies depending on atmospheric conditions
• Nitrogen, oxygen, and argon gases comprise about 99.97% of the Earth's atmosphere
• The rest of the atmosphere is composed of varying amounts of water vapor, carbon dioxide (CO2) and traces of inert gases
• Carbon dioxide (CO2)


  Small amount (0.03%) but equally important to life on Earth, continuously cycled through photosynthesis and respiration
• Aerosols


  Dusts, smoke, salt crystals, and tiny solid or liquid particles suspended and distributed in the atmosphere
• Aerosols


  • Act as surfaces on which water vapor can condense to form clouds or fog
  • Absorb, reflect, and scatter incoming heat from the sun
  • Contribute to the different hues of red and orange during sunrise and sunset
• Temperature decreases as altitude increases in the troposphere
• Troposphere

  Lowermost layer of the atmosphere, where most weather phenomena occur, and most clouds are found