01:460:202 Lecture Notes - Lecture 14: Earth'S Energy Budget, Westerlies, 2Degrees
30 Jul 2018
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• Composition of the modern atmosphere
o Nitrogen (78%), Oxygen (20%), Argon (1%), Neon/Helium/Krypton (.0025%)
• Greenhouse gases- who they are and what they do
o Water vapor (H2O), methane (CH4), and carbon dioxide (CO2)
o They keep Earth’s climate from being unbearably cold
• Structure of atmosphere and properties of atmospheric layers
o Four layers:
▪ Troposphere
• 7 km- 17 km thick
• Temperate change is related to the heating of the Earth’s surface
by solar radiation—cools upward to tropopause
• The most dynamic place within the atmosphere: life lives,
weather occurs; about half of the mass of the atmosphere is in
the lower 5 km of the troposphere
▪ Stratosphere
• Contains the ozone layer
• Temperatures increase upward through the stratosphere
• Higher temperatures of the stratosphere vs. those of the
underlying troposphere prevent air from rising and crossing the
boundary zone (the tropopause)
• Top is marked by a temperature decrease (boundary called the
stratopause)
• Where most weather occurs
▪ Mesosphere
▪ Exosphere
o Temperature variations define these layers
• Ozone layer and its benefits
o Within the stratosphere
