Physical Structure of the Atmosphere

Physical Structure of the Atmosphere

• Composed of multiple layers with minimal chemical interaction.
• Approximately 50% of the atmosphere's mass is located within 6 km of the Earth's surface.
• Atmospheric pressure decreases with height; over 99% of energy is captured close to the surface.

Layers of the Atmosphere

• Troposphere: Contains most clouds, holds about 4/5 of the atmosphere's mass.
• Stratosphere: Home to the ozone layer with the ozone maximum.
• Mesosphere: Interacts with UV rays, cosmic rays, and meteors.
• Thermosphere/Ionosphere: Known for ionization of gases.
• Exosphere: The outermost layer of the atmosphere.

Chemical Structure of the Atmosphere

• Major components:
  • 78% Nitrogen
  • 20.6% Oxygen
  • Less than 1% Argon
  • 0.4% Water vapor
  • 0.036% Carbon dioxide
• Trace gases include Neon, Helium, Krypton, Hydrogen, Ozone, Methane, and Nitrous Oxide.

The Greenhouse Effect

• Earth's surface energy sources: the Sun and atmosphere make the surface approximately 33°C warmer than it would be without the atmosphere.
• Greenhouse gases are transparent to shortwave radiation but absorb longwave radiation, enabling the atmosphere to store energy.
• The greenhouse effect enhances Earth's average surface temperature by 20-30°C as a result of infrared radiation emission.

Historical Context

• The greenhouse effect was discovered by Joseph Fourier in 1829.
• Svante Arrhenius quantitatively investigated the greenhouse effect in 1896.
• The phenomenon is analogous to the warming of air within a greenhouse compared to outside temperatures.