The Earth's Atmosphere - Chapter 1

• Weather vs. Climate (NYC climate graph)
• Atmospheric Hazards (Billion Dollar Weather Events)
• The Nature of Scientific Inquiry
• Earth's Spheres
  • The Geosphere
  • The Atmosphere
  • The Hydrosphere
  • The Biosphere
• Earth System Science
  • What is a system?
  • Feedback Mechanisms
    • negative feedback mechanisms
    • positive feedback mechanisms
  • The Earth System
    • Carbon Cycle
    • Hydrologic Cycle
    • Rock Cycle
    • Energy Systems

Composition & Structure of the Atmosphere

• The Earth's atmosphere is held in place by gravity.
• The atmosphere is densest at the surface and rapidly thins upward.
• 97% of the atmosphere is found within 18 miles of the Earth's surface.
• Gasses that make up the atmosphere
• Changes in atmospheric CO₂
• Atmospheric pressure
  • measurement units
    • 14.7 lbs/inch² = 1013 millibars =
      1 atmosphere = 29.92 inches of Hg = 760mm of Hg
  • measuring air pressure
    • mercury barometer
    • aneroid barometer
    • aneroid barograph
• Vertical Distribution of Atmospheric Pressure
  • 50% of the Earth's atmosphere found below 20,000 feet.
  • 95% below 65,000 feet
  • Atmospheric pressure variation with altitude.
  • Oxygen and Human Requirements
  • Partial Pressure
  • Adapting to High Altitudes
• Ozone
  • Ozone creation
  • Ozone depletion - 1
  • Ozone depletion - 2
  • Changes in ozone area - graph
  • Changes in the ozone hole - image
• Thermal Structure of the Atmosphere (from lowest to highest elevation)
• troposphere
  • environmental lapse rate - 3.6^oF/1000 feet or 0.65^oC/100 meters
  • if sea level temperature is 80^oF,
    at 40,000 feet temperature is -64^oF
  • at about 48,000 feet, lapse rate remains constant with elevation increase (tropopause)
  • contains water vapor and huge amounts of dust which act as condensation nuclei
  • tropopause height differences (colder air more dense, warmer air less dense, tropopause higher in tropics)
• stratosphere
  • temps remain nearly constant to 12 miles (65,000 ft) and then increase rapidly to the stratopause (30 miles (160,000 ft). Max ozone at approximately 25 miles.
• mesosphere
• thermosphere
• Thermal Structure of the Atmosphere