The Earth and Its Atmosphere

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The Earth and Its Atmosphere

• Chapter 1

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There is no upper limit of the atmosphere, but it
rather becomes thinner and thinner, merging with
empty space.
-laughing gas
greenhouse effect warming that results when
solar radiation is trapped by the atmosphere
caused by atmospheric gases that allow sunshine
to pass through but absorb heat that is radiated
back from the warmed surface of the earth.
Water is the only substance that can be found
naturally in the atmosphere in its 3 phases
(solid-gtice, liquid-gtwater, gas-gtwater vapor)
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Carbon Dioxide cycle
Fig. 1-4, p. 7
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Vertical Structure of the Atmosphere

• Air Pressure and Air Density
• Weight (force acting on an object due to gravity)
  
• mass x gravitational acceleration m x g
• Density mass/volume (air density at sea level
  1.2 kg/m3 )
• Pressure force/area
• At the Earths surface the pressure of the
  atmosphere is 14.7 lbs/in2 .
• Standard sea level pressure is
  1013.25mb1013.25hPa29.92 in.Hg.
• Atmospheric pressure decreases with an increase
  in height.

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9km
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Vertical Structure of the Atmosphere

• Layers of the Atmosphere
• Pressure Density decrease with height
• Air temperature has a complicated vertical
  profile
• Lapse rate the rate of change (decrease) in
  temperature with a change in height the average
  lapse rate in Troposphere - 6.5 C / 1 km.
• Inversion layer change in the sign of the lapse
  rate, 6.5 C / 1 km.
• Isothermal environment no change in temperature
  with height

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Layers of the atmosphere as related to
average profile of air temperature.
Fig. 1-11, p. 13
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Vertical Structure of the Atmosphere

• Observation Radiosonde
• Weather balloon
• Instrument and transmitter
• Air temperature, humidity, pressure

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Vertical Structure of the Atmosphere

• The Ionosphere
• Not a true layer but an electrified region within
  the upper atmosphere (from about 60 km to the top
  of the atmosphere) where fairly large
  concentrations of ions and free electrons exist.
• Ions molecule with an additional or minus an
  electron
• Sun light creates layers F (at 180 km) ,E (at
  120 km),D (at 60 km) layers
• Ionosphere plays a major role in AM radio
  communications

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At night, the F region of ionosphere strongly
reflects AM radio waves, allowing them to be sent
over great distances. During the day, the lower D
region strongly absorbs and weakens AM radio
waves, preventing them from being picked up by
distant receivers.
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(more solar eruptions)
Based on composition of the atmosphere
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Weather and Climate

• Weather short term changing in air temperature,
  air pressure, humidity, clouds, precipitation,
  visibility, and wind
• Climate long term patterns and average weather
  not just magnitude but also frequency
• Assignment 1

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Weather Climate

• Meteorology
• Study of the atmosphere and its phenomena
• Aristotle 340 B.C. book on natural philosophy,
  Meterologica. Greek word meteoros high in
  air sum of knowledge at that time
• The birth of Meteorology as a natural science did
  not take place until the invention of weather
  instruments thermometer ( end of 16th century),
  barometer (17th century), hygrometer (18th
  century).
• 1843 telegraph invented
• 1920s concepts of air masses and fronts
• 1940s upper air balloons
• 1950s radar and computers
• 1960s satellite

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Doppler radar has the capacity of estimating
rainfall intensity.
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Weather Climate

• Satellites View
• Geostationary satellite situated at about
  36,000Km (22,300mi) above the earth. Satellite
  travels at the same rate as the earth spins,
  which allows it to remain positioned above the
  same spot.
• Meridians measure longitude (W-E) lines running
  from north to south. Prime meridian (00meridian)
  runs through Greenwich, England.
• Parallels to equator (00latitude) measure
  latitude (N-S)
• Weather maps pressure cells, fronts, surface
  stations

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Satellite Image clouds storms at surface
Fig. 1-15, p. 20
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Simplified surface weather map that correlates
with the satellite image shown .
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Weather Climate

• Weather and Climate in Our Lives
• Two general reasons for studying how weather and
  climate impacts our lives economic efficiency
  and public safety.
• Crops
• Utilities
• Extreme cold and heat
• Tornados and hurricanes
• Clothing
• Meteorologist
• Any person with a college degree in meteorology
  or atmospheric science not just the TV weather
  person
• Half of 9000 meteorologists employed by the US
  National Weather Service
• Researchers and operational meteorologists

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Energy Warming the earth and Atmosphere

• Chapters 2 and 19

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Energy, Temperature, Heat

• Energy is the ability to do work (push, pull,
  lift) on some form of matter.
• Potential energy is the potential for work.
  Gravitational potential energy
• Kinetic energy is energy of a moving object
• Total energy PE KE
• Temperature is a measure of the average speed of
  atoms and molecules.
• High temperature ? corresponds to high average
  speeds

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Cold, more dense air
Warm, less dense air
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Energy, Temperature, Heat

• Which has more energy?
• A lake or a cup of hot tea?
• Heat is the energy in the process of being
  transferred from one object to another because of
  a difference in temperature.
• First Law of Thermodynamics Energy cannot be
  destroyed or created ? conservation of energy

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Temperature Scales

• Fahrenheit (early 18th century) 32 freeze, 212
  boil
• (180 equal divisions)
• Celsius (later in the 18th century) 0 freeze,
  100 boil
• (100 equal divisions)
• Kelvin (19 century) absolute 0K -273C (no
  thermal motion)

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