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GEOG 100--Lecture 04--Energy, seasons, atmos

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GEOG 100--Lecture 04--Energy, seasons, atmos

  1. 1. Physical Geography Lecture 4EARTH’S ENERGY, SEASONS, AND ATMOSPHERE
  2. 2. Electromagnetic Radiation All objects emit (radiate) EMR—waves that can transport energy w/out requiring a medium (matter) to pass through One of the most fundamental forms of energy in our universe Given off as waves Different wavelengths have different properties
  3. 3. Shortwave vs. LongwaveRadiation Electromagnetic radiation waves are measured in micrometers (µm)
  4. 4. Two important principles of electromagnetic radiation emissions:1. There is an inverse relationship between the wavelength of radiation an object emits and the temperature of that object Long-wave = cool object Short-wave = hot object (Examples: iced tea vs. hot tea)2. Hot objects radiate more energy than cool objects
  5. 5. What do you think?
  6. 6. What do you think? Which one will emit MORE electromagnetic radiation? The Sun Earth
  7. 7. What do you think? Which one will emit MORE electromagnetic radiation? The Sun Earth Which one will emit mostly short-wave radiation?
  8. 8. What do you think? Which one will emit MORE electromagnetic radiation? The Sun Earth Which one will emit mostly short-wave radiation? The Sun Earth
  9. 9. InsolationIncoming Solar Radiation—EMR coming from our sun
  10. 10. Properties of Solar Radiation
  11. 11. Properties of Solar Radiation Sol—Our star
  12. 12. Properties of Solar Radiation Sol—Our star  a ball of gases heated by constant nuclear reactions
  13. 13. Properties of Solar Radiation Sol—Our star  a ball of gases heated by constant nuclear reactions  Surface temperature = 11,000°F (6000°C)
  14. 14. Properties of Solar Radiation Sol—Our star  a ball of gases heated by constant nuclear reactions  Surface temperature = 11,000°F (6000°C)
  15. 15. Properties of Solar Radiation Sol—Our star  a ball of gases heated by constant nuclear reactions  Surface temperature = 11,000°F (6000°C) Radiation travels outward in all directions at a speed of 186,000 mps (300,000 kps)
  16. 16. Properties of Solar Radiation Sol—Our star  a ball of gases heated by constant nuclear reactions  Surface temperature = 11,000°F (6000°C) Radiation travels outward in all directions at a speed of 186,000 mps (300,000 kps)  Takes 8 1/3 minutes to get to Earth (approx. 93 mil. miles away!)
  17. 17. Properties of Solar Radiation Sol—Our star  a ball of gases heated by constant nuclear reactions  Surface temperature = 11,000°F (6000°C) Radiation travels outward in all directions at a speed of 186,000 mps (300,000 kps)  Takes 8 1/3 minutes to get to Earth (approx. 93 mil. miles away!)  Reduction of wave energy as it spreads out
  18. 18. Properties of Solar Radiation Sol—Our star  a ball of gases heated by constant nuclear reactions  Surface temperature = 11,000°F (6000°C) Radiation travels outward in all directions at a speed of 186,000 mps (300,000 kps)  Takes 8 1/3 minutes to get to Earth (approx. 93 mil. miles away!)  Reduction of wave energy as it spreads out  Earth receives ½ of 1/billionth of the sun’s total energy
  19. 19. Properties of Solar Radiation
  20. 20. Properties of Solar Radiation Most of the sun’s emissions are in the form of short-wave radiation
  21. 21. Properties of Solar Radiation Most of the sun’s emissions are in the form of short-wave radiation  high in the visible light spectrum and short-wave infrared
  22. 22. Properties of Solar Radiation Most of the sun’s emissions are in the form of short-wave radiation  high in the visible light spectrum and short-wave infrared Visible light
  23. 23. Properties of Solar Radiation Most of the sun’s emissions are in the form of short-wave radiation  high in the visible light spectrum and short-wave infrared Visible light  Wavelength of 0.4 to 0.7 µm
  24. 24. Properties of Solar Radiation Most of the sun’s emissions are in the form of short-wave radiation  high in the visible light spectrum and short-wave infrared Visible light  Wavelength of 0.4 to 0.7 µm  Color is determined by wavelength
  25. 25. Properties of Solar Radiation Most of the sun’s emissions are in the form of short-wave radiation  high in the visible light spectrum and short-wave infrared Visible light  Wavelength of 0.4 to 0.7 µm  Color is determined by wavelength  Even when there is enough light to see shapes, can you see colors in a darkened room?
  26. 26. The Solar Constant
  27. 27. The Solar Constant Amount of radiation from the sun is nearly constant
  28. 28. The Solar Constant Amount of radiation from the sun is nearly constant Atmospheric conditions and reflection cause a reduction of this radiation within Earth’s atmosphere
  29. 29. The Solar Constant Amount of radiation from the sun is nearly constant Atmospheric conditions and reflection cause a reduction of this radiation within Earth’s atmosphere What we’re starting with is called the Solar Constant:
  30. 30. The Solar Constant Amount of radiation from the sun is nearly constant Atmospheric conditions and reflection cause a reduction of this radiation within Earth’s atmosphere What we’re starting with is called the Solar Constant:  The amount of solar energy received on a fixed surface area held outside Earth’s atmosphere at right angles to suns rays.
  31. 31. The Solar Constant Amount of radiation from the sun is nearly constant Atmospheric conditions and reflection cause a reduction of this radiation within Earth’s atmosphere What we’re starting with is called the Solar Constant:  The amount of solar energy received on a fixed surface area held outside Earth’s atmosphere at right angles to suns rays.  1400 Watts/m2
  32. 32. The Solar Constant Amount of radiation from the sun is nearly constant Atmospheric conditions and reflection cause a reduction of this radiation within Earth’s atmosphere What we’re starting with is called the Solar Constant:  The amount of solar energy received on a fixed surface area held outside Earth’s atmosphere at right angles to suns rays.  1400 Watts/m2
  33. 33. The Solar Constant Amount of radiation from the sun is nearly constant Atmospheric conditions and reflection cause a reduction of this radiation within Earth’s atmosphere What we’re starting with is called the Solar Constant:  The amount of solar energy received on a fixed surface area held outside Earth’s atmosphere at right angles to suns rays.  1400 Watts/m2 What happens to that insolation once it enters the atmosphere will affect Earth’s energy budget (determining surpluses or deficits) and, ultimately, our planet’s global heat balance
  34. 34. Insolation Levels
  35. 35. Insolation Levels Different parts of Earth receive different amounts of insolation
  36. 36. Insolation Levels Different parts of Earth receive different amounts of insolation The amount of insolation received depends on two things:
  37. 37. Insolation Levels Different parts of Earth receive different amounts of insolation The amount of insolation received depends on two things:  The angle of the sun’s exposure
  38. 38. Insolation Levels Different parts of Earth receive different amounts of insolation The amount of insolation received depends on two things:  The angle of the sun’s exposure  The length of exposure (length of the day)
  39. 39. Insolation Levels Different parts of Earth receive different amounts of insolation The amount of insolation received depends on two things:  The angle of the sun’s exposure  The length of exposure (length of the day) Both of these depend on:
  40. 40. Insolation Levels Different parts of Earth receive different amounts of insolation The amount of insolation received depends on two things:  The angle of the sun’s exposure  The length of exposure (length of the day) Both of these depend on:  Latitude
  41. 41. Insolation Levels Different parts of Earth receive different amounts of insolation The amount of insolation received depends on two things:  The angle of the sun’s exposure  The length of exposure (length of the day) Both of these depend on:  Latitude  Season
  42. 42. Earth in Space The Plane of the Ecliptic
  43. 43. Some Important Points(and Lines!) to Remember…
  44. 44. The Plane of the Ecliptic
  45. 45. Variations in Earth’s Motion
  46. 46. Variations in Earth’s Motion Changes to Earth’s declination
  47. 47. Variations in Earth’s Motion Changes to Earth’s declination  axial tilt (declination) varies from 21°59’ to 24°36’ over the course of about 40,000 years
  48. 48. Variations in Earth’s Motion Changes to Earth’s declination  axial tilt (declination) varies from 21°59’ to 24°36’ over the course of about 40,000 years  (it’s currently 23°2628")
  49. 49. Variations in Earth’s Motion Changes to Earth’s declination  axial tilt (declination) varies from 21°59’ to 24°36’ over the course of about 40,000 years  (it’s currently 23°2628") Precession
  50. 50. Variations in Earth’s Motion Changes to Earth’s declination  axial tilt (declination) varies from 21°59’ to 24°36’ over the course of about 40,000 years  (it’s currently 23°2628") Precession  this off-centered wobble changes shape over the course of about 26,000 years
  51. 51. Variations in Earth’s Motion Changes to Earth’s declination  axial tilt (declination) varies from 21°59’ to 24°36’ over the course of about 40,000 years  (it’s currently 23°2628") Precession  this off-centered wobble changes shape over the course of about 26,000 years Orbital variations
  52. 52. Variations in Earth’s Motion Changes to Earth’s declination  axial tilt (declination) varies from 21°59’ to 24°36’ over the course of about 40,000 years  (it’s currently 23°2628") Precession  this off-centered wobble changes shape over the course of about 26,000 years Orbital variations  Earth’s orbit changes from elliptical to circular and back over the course of about 93,000 years
  53. 53. Earth’s Orbit
  54. 54. Why Earth’s Axial Tilt Is So Important
  55. 55. Solstices
  56. 56. Solstices• Subsolar point (vertical ray)
  57. 57. Solstices• Subsolar point (vertical ray) Sun’s rays are directly overhead
  58. 58. Solstices• Subsolar point (vertical ray) Sun’s rays are directly overhead• Summer/June solstice
  59. 59. Solstices• Subsolar point (vertical ray) Sun’s rays are directly overhead• Summer/June solstice on or about June 22
  60. 60. Solstices• Subsolar point (vertical ray) Sun’s rays are directly overhead• Summer/June solstice on or about June 22• Winter/December solstice
  61. 61. Solstices• Subsolar point (vertical ray) Sun’s rays are directly overhead• Summer/June solstice on or about June 22• Winter/December solstice on or about December 22
  62. 62. Solstices• Subsolar point (vertical ray) Sun’s rays are directly overhead• Summer/June solstice on or about June 22• Winter/December solstice on or about December 22• Circle of Illumination
  63. 63. Solstices• Subsolar point (vertical ray) Sun’s rays are directly overhead• Summer/June solstice on or about June 22• Winter/December solstice on or about December 22• Circle of Illumination divides the day side and night side of Earth
  64. 64. Equinoxes
  65. 65. Equinoxes• Vernal (Spring) equinox
  66. 66. Equinoxes• Vernal (Spring) equinox on or about March 22
  67. 67. Equinoxes• Vernal (Spring) equinox on or about March 22• Autumnal (Fall) equinox
  68. 68. Equinoxes• Vernal (Spring) equinox on or about March 22• Autumnal (Fall) equinox on or about September 23
  69. 69. For further study: Visit the Khan Academy website: http://www.khanacademy.org/ science/cosmology-and-astronomy/ The following video sections relate to this lecture:  Introduction to light (from 6:38 to end)  Seasons aren’t dictated by closeness to the sun  How Earth’s tilt causes seasons
  70. 70. Ready for a quick review?
  71. 71. Ready for a quick review?1. What’s the difference between shortwave and longwave electromagnetic radiation? Which of these does Earth give off more?
  72. 72. Ready for a quick review?1. What’s the difference between shortwave and longwave electromagnetic radiation? Which of these does Earth give off more?2. What are the two important principles of EMR emissions?
  73. 73. Ready for a quick review?1. What’s the difference between shortwave and longwave electromagnetic radiation? Which of these does Earth give off more?2. What are the two important principles of EMR emissions?3. What is the solar constant? Why do we care?
  74. 74. Ready for a quick review?1. What’s the difference between shortwave and longwave electromagnetic radiation? Which of these does Earth give off more?2. What are the two important principles of EMR emissions?3. What is the solar constant? Why do we care?4. The amount of insolation received by an area on Earth’s surface depends on what?
  75. 75. 5. How are the Tropics of Cancer and Capricorn related to Earth’s axial tilt?
  76. 76. 5. How are the Tropics of Cancer and Capricorn related to Earth’s axial tilt?6. How are the Arctic and Antarctic Circles related to Earth’s axial tilt?
  77. 77. 5. How are the Tropics of Cancer and Capricorn related to Earth’s axial tilt?6. How are the Arctic and Antarctic Circles related to Earth’s axial tilt?7. What are aphelion and perihelion? On about what date do they occur?
  78. 78. 5. How are the Tropics of Cancer and Capricorn related to Earth’s axial tilt?6. How are the Arctic and Antarctic Circles related to Earth’s axial tilt?7. What are aphelion and perihelion? On about what date do they occur?8. True or false? Earth’s axial tilt shifts over time. By 2015, it will be 25°.
  79. 79. 5. How are the Tropics of Cancer and Capricorn related to Earth’s axial tilt?6. How are the Arctic and Antarctic Circles related to Earth’s axial tilt?7. What are aphelion and perihelion? On about what date do they occur?8. True or false? Earth’s axial tilt shifts over time. By 2015, it will be 25°.9. What causes Earth’s seasons?
  80. 80. 5. How are the Tropics of Cancer and Capricorn related to Earth’s axial tilt?6. How are the Arctic and Antarctic Circles related to Earth’s axial tilt?7. What are aphelion and perihelion? On about what date do they occur?8. True or false? Earth’s axial tilt shifts over time. By 2015, it will be 25°.9. What causes Earth’s seasons?10. What is the subsolar point? How is it related to the solstices and equinoxes?
  81. 81. How is insolation “processed” by Earth’s atmosphere?
  82. 82. Air is...where?
  83. 83. Air is...where? Air has weight, it has mass
  84. 84. Air is...where? Air has weight, it has mass Air is attracted by Earth’s gravity
  85. 85. Composition of the Atmosphere
  86. 86. Composition of the Atmosphere The atmosphere is composed of two types of gases:
  87. 87. Composition of the Atmosphere The atmosphere is composed of two types of gases: 1. Those which generally do not change their concentrations from place to place
  88. 88. Composition of the Atmosphere The atmosphere is composed of two types of gases: 1. Those which generally do not change their concentrations from place to place 2. Those which do
  89. 89. Proportional Volume of Atmospheric Gases
  90. 90. Particulates in the Atmosphere
  91. 91. The Importance of Particulates
  92. 92. The Importance of Particulates Absorb and reflect sunlight
  93. 93. The Importance of Particulates Absorb and reflect sunlight  This reduces the amount of sunlight that reaches Earth’s surface
  94. 94. The Importance of Particulates Absorb and reflect sunlight  This reduces the amount of sunlight that reaches Earth’s surface Scatter sunlight
  95. 95. The Importance of Particulates Absorb and reflect sunlight  This reduces the amount of sunlight that reaches Earth’s surface Scatter sunlight  Mostly in the blue range of the spectrum, giving the sky its blue color
  96. 96. The Importance of Particulates Absorb and reflect sunlight  This reduces the amount of sunlight that reaches Earth’s surface Scatter sunlight  Mostly in the blue range of the spectrum, giving the sky its blue color  At sunrise and sunset, most of the blue has been scattered in the upper atmosphere, leaving red and yellow
  97. 97. The Importance of Particulates They also act as condensation nuclei...
  98. 98. Condensation Nuclei
  99. 99. Condensation Nuclei Condensation nuclei are necessary elements for the formation of cloud droplets
  100. 100. Condensation Nuclei Condensation nuclei are necessary elements for the formation of cloud droplets Without them, conditions may be perfect for the formation of clouds or fog, yet condensation will not occur
  101. 101. Condensation Nuclei Condensation nuclei are necessary elements for the formation of cloud droplets Without them, conditions may be perfect for the formation of clouds or fog, yet condensation will not occur Excess condensation nucleii also may cause condensation before the saturation point has been reached
  102. 102. Condensation Nuclei Condensation nuclei are necessary elements for the formation of cloud droplets Without them, conditions may be perfect for the formation of clouds or fog, yet condensation will not occur Excess condensation nucleii also may cause condensation before the saturation point has been reached Some particles are hygroscopic—they attract and absorb water (salt)
  103. 103. Vertical Structure of the Atmosphere
  104. 104. Thermal Structure of the Atmosphere Troposphere  Temp. decreases with increasing altitude (surface warmed by the sun is its heat source)
  105. 105. Conduction Conduction is the passing of heat from molecule to molecule by touch
  106. 106. Conduction Temperature is an expression of molecular motion As one molecule bangs into another, it makes the next one vibrate, as well—thus passing on its molecular motion and increasing the temperature of the molecule it just “sped up” Thus the heat passes up the metal bar until it reaches the hand holding it…
  107. 107. Conduction in the Troposphere
  108. 108. Conduction in the Troposphere The sun’s radiation is absorbed at Earth’s surface and reradiated upward as heat
  109. 109. Conduction in the Troposphere The sun’s radiation is absorbed at Earth’s surface and reradiated upward as heat But air is a poor conductor of heat (the molecules are too far apart and move around too much)
  110. 110. Conduction in the Troposphere The sun’s radiation is absorbed at Earth’s surface and reradiated upward as heat But air is a poor conductor of heat (the molecules are too far apart and move around too much) So heat is not transferred upward very far
  111. 111. Conduction in the Troposphere The sun’s radiation is absorbed at Earth’s surface and reradiated upward as heat But air is a poor conductor of heat (the molecules are too far apart and move around too much) So heat is not transferred upward very far This is why the Troposphere is warmest at the surface and gets colder as you rise upward
  112. 112. ELR The rate at which air temperature drops as you rise through the Troposphere can be roughly estimated:  6.5ºC/1000 m or 3.5ºF/1000 ft This rate is called the Environmental Temperature Lapse Rate, or ELR
  113. 113. Thermal Structure of the Atmosphere Troposphere  Temp. decreases with increasing altitude (surface warmed by the sun is its heat source) Stratosphere  Temp. increases as ozone absorbs UV light
  114. 114. A Little Bit About theImportance of Ozone…
  115. 115. The Ozone Hole
  116. 116. Thermal Structure of the Atmosphere Troposphere  Temp. decreases with increasing altitude (surface warmed by the sun is its heat source) Stratosphere  Temp. increases as ozone absorbs UV light Mesosphere  Temp. decreases (no heat source)
  117. 117. Thermal Structure of the Atmosphere Troposphere  Temp. decreases with increasing altitude (surface warmed by the sun is its heat source) Stratosphere  Temp. increases as ozone absorbs UV light Mesosphere  Temp. decreases (no heat source) Thermosphere  Temp. increases as stratified layers of gases absorb high- intensity ultraviolet radiation and are split apart
  118. 118. Thermal Structure of the Atmosphere Troposphere  Temp. decreases with increasing altitude (surface warmed by the sun is its heat source) Stratosphere  Temp. increases as ozone absorbs UV light Mesosphere  Temp. decreases (no heat source) Thermosphere  Temp. increases as stratified layers of gases absorb high- intensity ultraviolet radiation and are split apart Exosphere  Merging into space  So few molecules of gas in this layer that “temperature” really doesn’t apply
  119. 119. Vertical Structure of the Atmosphere
  120. 120. Vertical Structure of the Atmosphere Ionosphere—begins in the Mesosphere  blocks extremely harmful short wave radiation (UV-B and UV-C), some cosmic rays, and high energy particles from the sun  reflects radio waves back to the surface, aiding long- distance communications  source of the arorae (borealis and australis), a.k.a. the Northern and Southern Lights
  121. 121. Vertical Structure of the Atmosphere Ionosphere—begins in the Mesosphere  blocks extremely harmful short wave radiation (UV-B and UV-C), some cosmic rays, and high energy particles from the sun  reflects radio waves back to the surface, aiding long- distance communications  source of the arorae (borealis and australis), a.k.a. the Northern and Southern Lights Homosphere  Mixed gases in roughly equal concentrations
  122. 122. Vertical Structure of the Atmosphere Ionosphere—begins in the Mesosphere  blocks extremely harmful short wave radiation (UV-B and UV-C), some cosmic rays, and high energy particles from the sun  reflects radio waves back to the surface, aiding long- distance communications  source of the arorae (borealis and australis), a.k.a. the Northern and Southern Lights Homosphere  Mixed gases in roughly equal concentrations Heterosphere  Gases so far from Earth’s surface that the effect of gravity is minimized—gases are stratified (layered) by molecular weight
  123. 123. A little more review:
  124. 124. A little more review:1. Why are most of Earth’s atmospheric gases found near the surface?
  125. 125. A little more review:1. Why are most of Earth’s atmospheric gases found near the surface?2. Name 3 important variable-amount gases found in Earth’s atmosphere. Why is each one important?
  126. 126. A little more review:1. Why are most of Earth’s atmospheric gases found near the surface?2. Name 3 important variable-amount gases found in Earth’s atmosphere. Why is each one important?3. Why are atmospheric particulates important?
  127. 127. A little more review:1. Why are most of Earth’s atmospheric gases found near the surface?2. Name 3 important variable-amount gases found in Earth’s atmosphere. Why is each one important?3. Why are atmospheric particulates important?4. What would happen if there were no condensation nuclei in the atmosphere? What happens when there is an abundance of nuclei?
  128. 128. 5. What is ozone? In which thermal layer of the atmosphere is it found? How does it affect temperatures within that layer?
  129. 129. 5. What is ozone? In which thermal layer of the atmosphere is it found? How does it affect temperatures within that layer?6. What generally happens to the surrounding air temperature as you rise through the troposphere?
  130. 130. 5. What is ozone? In which thermal layer of the atmosphere is it found? How does it affect temperatures within that layer?6. What generally happens to the surrounding air temperature as you rise through the troposphere?7. What happens in the -pauses?
  131. 131. 5. What is ozone? In which thermal layer of the atmosphere is it found? How does it affect temperatures within that layer?6. What generally happens to the surrounding air temperature as you rise through the troposphere?7. What happens in the -pauses?8. What is conduction? Is air a good conductor of heat?
  132. 132. 5. What is ozone? In which thermal layer of the atmosphere is it found? How does it affect temperatures within that layer?6. What generally happens to the surrounding air temperature as you rise through the troposphere?7. What happens in the -pauses?8. What is conduction? Is air a good conductor of heat?9. What is the ELR? What is the rate of change of the ELR? To which thermallayer of the atmosphere does it apply?
  133. 133. 5. What is ozone? In which thermal layer of the atmosphere is it found? How does it affect temperatures within that layer?6. What generally happens to the surrounding air temperature as you rise through the troposphere?7. What happens in the -pauses?8. What is conduction? Is air a good conductor of heat?9. What is the ELR? What is the rate of change of the ELR? To which thermallayer of the atmosphere does it apply?10.What is the homosphere? What is the heterosphere? What does the ionosphere do?
  134. 134. Quests of the day:Draw and label the seasons diagram in anotebookDraw the vertical structure of the atmospherediagram in a notebookWatch a Khan Academy video (or two...or three)Read the assigned chapter(s). Take notes.Write questions in the margins.Review the class slidesStudy for the quiz!

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