Lab 2: Vertical Structure of the Atmosphere

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Lab 2Vertical Structure of the Atmosphere
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Vertical Structure of the Atmosphere
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Vertical Structure of the Atmosphere

• The atmosphere is a compressible fluid
• Molecules are pulled to the earths surface by
  gravity
• Molecules are most compressed close to the
  earths surface
• Few molecules exist in earths gravitational
  field beyond 100km
• Considered arbitrary top to the atmosphere
• 90 of our atmosphere lies below 16km

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Vertical Structure of the Atmosphere

• Within the Atmosphere
• Density Decreases as Height Increases
• Rate For every 5.6 Km you go up in the
  atmosphere (ascend), there is ½ the atmospheric
  mass from when you started
• Called above (sea level)
• If gravitational pull is largest at the surface
  of the earth, then that too will decrease as you
  ascend. Connection?

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Vertical Structure of the Atmosphere

• Lab says We can assume that 100 of the
  atmospheric mass lies above sea level and exerts
  a pressure of approximately 1000 millibars (mb)
• Same rate applies as Above. Every 5.6 km,
  half the pressure exists

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Vertical Structure of the Atmosphere

• Partial Pressure of Gas
• Total Pressure (as determined by our graph)
• X
• Percentage of Gas in the Atmosphere
• Ex 1000mb x .78 (percent of Nitrogen)
• 780 mb

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Vertical Structure of the Atmosphere
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Vertical Structure of the Atmosphere

• Lapse rate the rate at which temperature
  changes with height
• Describes the vertical temperature structure of
  the troposphere.

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Vertical Structure of the Atmosphere

• Pressure density AND temperature decrease with
  altitude
• ?altitude ?air pressure temperature
• 1km? in altitude ? 6.5C in air temperature

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Vertical Structure of the Atmosphere

• Troposphere where most of the weather occurs
• Temperature decreases as height increases
• Tropopause Point between Troposphere and
  Stratosphere where there is no change in
  temperature

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Vertical Structure of the Atmosphere

• Tropospheric Lapse Rate takes an average
• Average air temperature at the surface of the
  earth is 15C
• Temperature decreases by 6.5C per kilometer
  until 11,000 km
• Why does it stop? Tropopause

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Vertical Structure of the Atmosphere

• Location of Tropopause varies with season
  latitude colder air has a higher density and
  lowers the height
• Thickness depends on high temperature thermal
  mixing
• Highest in the tropics

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Vertical Structure of the Atmosphere

• Ozone warms quickly in the stratosphere
• Absorbs heat from solar radiation and emits heat
  (perhaps stabilizing the decrease in the
  troposphere and increase in the stratosphere)
• Stratosphere does not warm at the same rate
  (unlike the troposphere which cools at the same
  rate) This is due to the ozone layer
• Ozone like urban heat island
• Radiation heating