50 miles thick

very thin

• N2-  78.1%
• O2- 20.9% 
• Argon (Ar)- .9%
• carbon dioxide (.039%) --> 5% increase per year
•  25% oxygen things can spontaneously combust

• sun is the primary source of energy on earth
• 1400 watts/m^2 at the top of the atmosphere
• drives the circulation of atmosphere/ocean 

must eat something else to get energy

ex) humans

can make there own food source

ex) phytoplankton

motion that drives our atmosphere

gases circulate from areas of hot low densities to areas of cold high densities 

1827, Fourier

the atmosphere traps greenhouse gases --> heats up earth

gases: water vapor, CO2, CH4, N2O, O3, CFCs

earth without greenhouse gases: -18 degrees C

earth with greenhouse gases: 15 degrees C

• h2O, CO2, CH4, N2O, O3, CFCs
• can only absorb longwave radiation
• earth's temp without greenhouse gases: -18 degrees celcius (-.4 degrees F)
• earth's temp with greenhouse gases: 15 degrees C (59 degrees F)

• uneven, variable heating of earth
• more sunlight when you're at the equator
• less light at the poles 
• causes seasons

• the fraction of incident electromagnetic radiation reflected by a surface (fraction of light reflected by a surface)

0-30 degrees

air warm at equator (0 degrees)

flows toward (30 degrees)

cools at (30 degrees)

returns to equator (0 degrees)

30-60 degrees

air warms at 60 degrees

flows toward 30 degrees

cools at 30 degrees

flows back to 60 degrees

60-90 degrees

air warms at 60 degrees

air flows toward 90 degrees

air cools at 90 degrees

air returns to 60 degrees 

intertropical convergence zone

where northeast trade winds and south east trade winds converge 

causes area of low pressure (doldrums)

• cool air cannot hold a lot of water vapor, so it is typically dry
• warm air can hold more water vapor: moist
•   water vapor decreases the density of air

• cool, dense air causes high pressure at surface --> sinking air
• warm, less dense air causes low pressure at surface --> rising air 

• tropics/poles are heated differently 
• heat redistribution: winds, ocean currents
• pressure gradient: changes in air density 

• incoming energy comes in through shortwave solar radiation (100)
• a lot gets reflected away: clouds, surface, backscatter
• 47% absorbed by ocean/land
• shortwaves come back out of the earth as long wave radiation, conduction, evaporation
• once it gets trapped in atmosphere, it is trapped (pinball effect)

• layers: organized by pressure (pascal)
• higher: less pressure 
• identify diff layers by temperature changes
• influctions/boundaries are called--pauses (topopause, stratopause, mesopause)
• troposphere
• stratosphere
• mesosphere
• thermosphere

heat buoyancy= makes the air rise/sink (+/-)

vertical motion of air (equator-rise, poles-sink)

influenced by pressure gradient force/coriolis force

caused by the rotation of the earth

can't make air move

take air that is moving and deflect it 

counterclockwise: deflects to the right

clockwise deflects to the left

light white areas reflects ice

ex) glacier 

dark areas

absorbs heat

ex) ocean