The Atmosphere

The Atmosphere has 7 layers but 4 important ones:

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere

The Troposphere:

• 1st layer closest to the earth
• 0-12km
• where most weather processes take place
• as height increases in this layer the temperature decreases aprox. -6.5'C every 1km
• it contains 75% of the earths gases
• the end of the troposhere is marked by the TROPOPAUSE, (an isothermal layer where temperature remains constant)

The Stratosphere:

• 2nd layer
• 13-50km
• this is where the planes fly approx. 37,000ft
• absorption of solar radiation by the ozone = steady increase in temperature
• atmosphere thinner in this zone as pressure decreases
• Stratopause = another isothermal layer the end of the stratosphere

The Mesosphere:

• 3rd layer
• 50-80km
• temperature decreases rapidly to - 100'C
• this layer protects the earth from meterorites as its so cold they burn up
• Mesopause - another isothermal layer the end of the mesosphere

The Thermosphere:

• 4th layer
• 80-400km
• increase in temperature to 2000'C +
• heatsphere rising and warming
• helps radio transmission