The Atmosphere, Energy in Processes, Insolation, Specific Heat,

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Chapter 26

• The Atmosphere, Energy in Processes, Insolation,
  Specific Heat, Isotherms

BFRB Topic 5 Topic 6
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Meteorology

• The study of weather
• Weather is the condition of the atmosphere at any
  given time or place
• Much of weather forecasting and prediction can be
  accomplished by direct observation LOOK OUT THE
  WINDOW!!
• To predict weather, you must make observations of
  the clouds, wind, temperature, humidity, air
  pressure and precipitation

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Atmospheric Composition

• The Earths atmosphere is made up of many gases,
  but it is mostly nitrogen and oxygen (ESRTs Page
  11 top)
• It also contains water vapor, dust, and ozone
  O3 (a form of oxygen which absorbs UVC rays from
  the sun)
• As you go higher in the atmosphere, the amount of
  air and air pressure (weight of air) decreases

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Structure of the Atmosphere

• Made up of four layers, each with different
  characteristics (ESRTs Page 14 top)
• Troposphere- lowest layer (we live in this
  layer). All of Earths weather occurs in the
  troposphere. Temperature decreases as you go
  higher.
• Stratosphere- above the troposphere, has strong
  winds. Temperature increases as you go higher
  because of the absorption of UV rays by ozone.
• Mesosphere- above the stratosphere. Temperature
  decreases as you go higher.
• Thermosphere- above the mesosphere. Temperature
  increases as you go higher due to oxygen and
  nitrogen absorbing solar energy

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ESRTs Page 14 top
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Movement of Heat 3 Ways

• 1) Conduction- the movement of heat from
  molecule to molecule through contact with each
  other or other objects
• Ex. Touching a hot pot on the stove

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Movement of Heat 3 Ways

• 2) Radiation- the movement of Electromagnetic
  Energy (heat waves) across a distance
• Ex. Warming your hands in front of a fireplace
• Earth receives EM energy radiated from the sun
  are relatively short wavelengths, and Earth
  reradiates this heat energy at longer wavelengths
  known as Infrared waves (heat)
• Energy received on Earth from the sun is called
  Insolation (incoming solar radiation)

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Movement of Heat 3 Ways

• 3) Convection- the movement of heat in currents
• The most effective form of heat transfer in
  liquids and gases
• Air gets heated and expands the molecules move
  apart - makes it less dense and lighterit rises!
  
• Colder air molecules come together - is more
  dense and heavier so it sinks
• It gets heated it rises, it cools it sinks
• Just like in the putty-like asthenosphere!!!!!

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CONVECTION CURRENT DUE TO DENSITY
DIFFERENCES!!!!!!!!!
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Greenhouse Effect

• Certain gases in the atmosphere (water vapor,
  carbon dioxide, methane, etc.) allow short
  wavelengths of energy from the sun to enter the
  atmosphere
• Earth absorbs them and reradiates the heat as
  infrared (heat) waves, which have longer
  wavelengths
• The infrared waves cannot pass back through these
  gases and escape into space, so they become
  trapped in the atmosphere
• This causes the temperature on Earth to increase.
• This is the cause of Global Warming.

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Temperature Changes on Earth

• Temperature changes with seasonal change occur
  because the suns insolation strikes Earth at
  different angles (and therefore different
  intensities)
• Where the suns rays strike Earth at 90, the
  insolation is concentrated in a smaller area.
  This causes temperatures to be the greatest.
• Where the suns rays hit Earth at very low
  angles, the insolation is spread out over a large
  area. This causes temperatures to be low.

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Warmest and Coldest Months

• Northern Hemisphere-
• Maximum sunlight is June 21st, but maximum
  temperature is in July there is a lag!!!
• Minimum sunlight is December 21st, but minimum
  temperatures are experienced in January there
  is a lag!!!
• It takes time for the heat to build up, and for
  maximum temperatures to be reached
• Also, it takes time for heat to dissipate, and
  for minimum temperatures to be reached

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Warmest and Coldest Time of Day

• The coldest hour is usually just before sunrise,
  since the Earth has been cooling off all night
  there is a lag!!!!
• The warmest time is later in the afternoon (after
  solar noon), since the Earth is still receiving
  more heat than it is losing there is a lag!!!

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Heating Water and Land

• Water and land heat up and cool off at different
  rates
• This is due to their different heat capacities
  AKA SPECIFIC HEAT (P. 1 of ESRTs)
• Land needs very little energy to heat up (low
  heat capacity)
• This allows land to heat up quickly, and also to
  cool down quickly
• Water needs more energy to heat up (high heat
  capacity)
• This allows water to heat up slowly and to cool
  off slowly -
• WATER IS STUBBORN!!! It takes a long time to heat
  up and a long time to cool down

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The Rules of Absorber and Reflectors

• Dark colors absorb energy well, and light colors
  reflect energy well (think...dark color clothes
  in winter, light colors clothes in summer)
• Rough surfaces absorb energy well, while smooth
  surfaces reflect energy well (thinka mirror is
  smooth and reflects your image really well.)
• VIF The best ABSORBERS make the best EMITTERS
  of energy.
• This is why radiators (heaters) are often black
  in color!!!

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How Does Waters High Specific Heat Affect
Weather Climate?

• Air temperature and other weather conditions of
  different locations are affected by how near or
  far they are from water (oceans) due to heat
  capacity
• VIF - Water has a mitigating effect to extremes
  of temperature and climate
• For example, a coastal city may have a average
  annual high of 75 and an average annual low of
  40. (35 range)
• An inland city may have an average annual high of
  82 and an average annual low of 33. (49 range)
• The coastal city is near the water, so the
  waters temperature doesnt change as quickly as
  the lands temperature due to waters high
  specific heat.

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ISOTHERMS

• Temperatures are shown on maps by using Isotherms
• These are lines which connect areas of equal
  temperature
• These are very similar to contour lines, and they
  are read the same way!!
• Example closely spaced isotherms mean a fast
  change in temperature the same way closely spaced
  contour lines mean a fast change in elevation.

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Where in the US is the steepest temperature
gradient? Where is the gentlest temperature
gradient?