GEOG100--Lecture 05--Atmos energy, temp, weather


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GEOG100--Lecture 05--Atmos energy, temp, weather

  1. 1. Chapter 3Atmospheric Energy andGlobal Temperatures
  2. 2. Earth’s Energy Balance or: What comes in must go out! The sun is the power source that drives many of Earth’s flow systems (storms, waves, ocean and wind currents) When the sun’s energy (sunlight) enters our atmosphere, its inputs must be balanced by equal outputs This energy must be redistributed over the globe to maintain the conditions of our current lifelayer 2
  3. 3. Surplus vs. Deficit A surplus in your checkbook is a good thing! A surplus of energy within Earth’s systems generally means an increase in temperature and changes in Earth’s systems’ circulations (NOT such a good thing!) 3
  4. 4. Net Radiation Net radiation is the difference between the radiation energy surplus and deficit Can be measured daily, monthly, yearly, even by century, in order to help us answer the question, “Are we heating up or cooling down?” Determining net radiation begins with a number of insolation losses in the atmosphere…
  5. 5. Hypothetical Radiation Balance
  6. 6. Reflection Albedo—the % of insolation reflected back to space
  7. 7. Scattering
  8. 8. Hypothetical Radiation Balance
  9. 9. Conduction
  10. 10. Convection
  11. 11. Convection
  12. 12. Hypothetical Radiation Balance
  13. 13. Counterradiation
  14. 14. The Greenhouse Effect
  15. 15. Hypothetical Radiation Balance
  16. 16. The Redistribution of Energy Sensible heat transfer  Latent heat transfer
  17. 17. Sensible Heat Sensible heat is heat that can be felt and measured  Moved by conduction; transferred by global winds and ocean currents
  18. 18. Latent Heat Latent heat cannot be sensed or directly measured  Heat that is stored or released during the change of state of solids, liquids, and gases  Movement occurs most often through condensation and evaporation (Ex.: the formation of clouds or the evaporation of ocean water)  Water in the atmosphere is the most important mover of latent heat, which ultimately helps to balance Earth’s energy budget
  19. 19. Review1.What is the power source that drives Earth’s flow systems?2.What happens if Earth’s energy inputs and outputs are unbalanced?3.Describe the different ways incoming solar radiation is balanced by outgoing radiation (draw a diagram, if that makes it easier to explain).
  20. 20. 4.What is albedo? What kinds of surfaces have a high albedo? What surfaces have a low albedo?5.Describe convection.6.What is counterradiation? What kinds of gases contribute to counterradiation? What is the greenhouse effect?7.What is the difference between sensible heat and latent heat?
  21. 21. Temperature Temperature—a measure of the level of sensible heat of matter; an expression of atomic motion  Heat moves from substances of higher temp. to substances of lower temp. until their temperatures equalize
  22. 22. Fahrenheit, Celsius, and Kelvin  Three systems of temperature measurement in use internationally: Fahrenheit, Celsius, and Kelvin  In order to convert from Fahrenheit to Celsius and back, use these formulae:  C° = 5/9 (F-32°)  F° = 9/5 C + 32°  0°K = absolute zero—the point at which all molecular motion ceases  -273.15°C or -459.67°F  Room temperature is about 295K  Converting K to °C only requires adding 273° (e.g. 3°C = 276K)  Especially useful when dealing with very low temperatures, as there are no negative numbers
  23. 23. Isotherms Isotherms— lines on a map that connect points of equal temperature
  24. 24. Daily and SeasonalTemperature Changes Daily temperatures are influenced by patterns of sunrise and sunset, which are the result of seasonal changes, themselves the result of latitude.
  25. 25. Daytime Temperatures:Normal Condition
  26. 26. Temperature Inversions  Temperatures are generally hotter during the day at the surface and cooler above.  A temperature inversion occurs when surface temperatures are cooler than the air above for some vertical distance.  Once a temperature inversion occurs, it tends to persist until all heat has been transferred back out to space.  There are four common types of temperature inversions….
  27. 27. Subsidence Inversion Subsidence inversions  Occur in the upper atmosphere  Result of air slowly descending due to a high pressure cell  As the air descends, it compresses and warms, and this warm layer sits atop cooler air below  Most common in the subtropics year-round and in the Northern Hemisphere in winter  Do not sink lower than a few hundred meters above sea level due to low-level turbulence
  28. 28. Radiational Inversion Radiational inversions—the result of rapid radiational cooling  Most common in high latitudes, especially at night  Long wave radiation (heat) is radiated back out to space and has left the lower portion of the troposphere, but has not yet entirely left the air above.
  29. 29. Advectional Inversion Advection = “wind” (any horizontal movement of air, usually in response to atmospheric pressure differences) Advectional inversions—a horizontal flow of air displaces warmer air upward  Especiallycommon along coasts, as air moves out of high pressure zones over the water and into a low pressure zone over land.
  30. 30. Filmore, CA
  31. 31. Cold-air-drainage Inversion Cold-air-drainage inversions—cooler air on mountain slopes sinks into a valley below, forcing the warmer air in the valley to rise upward Most common in the midlatitudes, especially in winter
  32. 32. Daily Temperature Lags Insolation levels rise as the sun rises, reach a maximum at noon, then decrease and end at sunset The coldest time of day is actually after the sun has risen The hottest time of day is a few hours after noon The hottest time of day (maximum daily temperature) varies based on such factors as cloudiness, windiness, proximity to a large body of water, and even storms.
  33. 33. Seasonal Temperature Lags In summer, monthly insolation is highest In winter, monthly insolation is lowest In between, during the equinoxes, insolation levels are in the middle Highest monthly temperatures tend to be one month after the summer solstice Lowest monthly temperatures also follow one month after the winter solstice Although radiation levels are similar for both the fall (autumnal) and spring (vernal) equinoxes, temperatures are considerably warmer following the summer months than following winter. The temperatures of the equinoxes are not the same because each reflects the temperatures of previous seasonal conditions.
  34. 34. Factors influencing differences intemperature Latitude Elevation/Altitude Cloud Cover and Albedo Proximity to a Water Body  Differential heating of land and water  Ocean currents Proximity to an urban area
  35. 35. Latitude January—Global Temperatures
  36. 36. Latitude July—Global Temperatures
  37. 37. Elevation As discussed previously…  Remember the ELR!
  38. 38. Cloud Cover and Albedo
  39. 39. Distribution of Land and Water: Properties of Land vs. Water
  40. 40. Proximity to a Water Body:Isotherms on a Hypothetical Continent
  41. 41. Proximity to a Water Body:Exterior (Coastal) vs. Interior (Continental) Locations
  42. 42. Latitude andOceans
  43. 43. Ocean Currents
  44. 44. General Circulation of the Oceans
  45. 45. Proximity to an Urban Area:The Urban Heat Island
  46. 46. Global Temperature Patterns: Mini Quiz! Which will be colder? Highland areas (areas of higher elevation) or lowland areas in the same region?  Highlands are colder than surrounding lowlands. Does temperature increase or decrease with latitude (as you get closer to the poles)?  It decreases. True or False? Seasonal isotherm shifts are more dramatic over land areas than over oceans.  True Which influences temperatures on the edges of continents: warm or cold ocean currents?  Both warm and cold currents affect temperatures on nearby land Equatorial locations receive a roughly even amount of insolation all year round. How does that affect their temperature patterns?  They tend to have more even temperature patterns
  47. 47. Review1.What is the difference between heat and temperature?2.True or False? Heat flows from the hot object toward the cold object until both objects are the same temperature.3.Lines on a map that connect points of equal temperature are called...4.Draw two graphs: one showing a normal atmospheric temperature condition and one showing a temperature inversion.5.Describe the 4 temperature inversions.
  48. 48. 6.The hottest time of day is just after noon and the coldest time is just after sunrise. Why?7.Name the 5 factors influencing the temperature of any location.8.Why does being near a body of water make a location warmer in winter and cooler in summer than locations further inland? (Remember the properties of land vs. water!)9.What is an urban heat island?
  49. 49. What is the difference between Weather and Climate?• Weather • Climate
  50. 50. What is the difference between Weather and Climate?• Weather • Climate Short-term atmospheric conditions (A storm or warm front)
  51. 51. What is the difference between Weather and Climate?• Weather • Climate Short-term atmospheric conditions (A storm or warm front)
  52. 52. What is the difference between Weather and Climate?• Weather • Climate Short-term An average of atmospheric weather conditions conditions over a long period of (A storm or warm front) time (minimum of 30 yrs.)
  53. 53. What is the difference between Weather and Climate?• Weather • Climate Short-term An average of atmospheric weather conditions conditions over a long period of (A storm or warm front) time (minimum of 30 yrs.)
  54. 54. “Choosing shorts or long underwear on aparticular day is about weather; the ratioof shorts to long underwear in the draweris about climate." --Charles Wohlforth, The whale and the supercomputer:On the northern front of climate change, p. 150 Climate is what entices you to go there on vacation…weather is what drives you to come home.
  55. 55. The 4 Basic Elements of Weather and Climate Temperature Moisture Content (Precipitation) Atmospheric Pressure Wind (strength, direction, constancy)
  56. 56. The 7 Controls of Weather and Climate Latitude Distribution of land and water General circulation of the atmosphere General circulation of the oceans Elevation Topographic barriers Storms
  57. 57. Latitude
  58. 58. Distribution of Land and Water
  59. 59. General Circulation of the Atmosphere
  60. 60. General Circulation of the Oceans
  61. 61. Ocean Circulation Patterns
  62. 62. Elevation
  63. 63. Topographic Barriers
  64. 64. Storms
  65. 65. Global Warming: An Informed Opinion 69
  66. 66. Global Warming: An Informed Opinion • An Inconvenient Truth • IPCC—Intergovernmental Panel on Climate Change • NRDC—Natural Resources Defense Council • EPA, NOAA, NESDIS—National Environmental Satellite, Data and Information Service, etc. vs. • CEI—Competitive Enterprises Institute ( • Global corporations—esp. carbon-based energy
  67. 67. What you’re learning is thescience behind the issues...
  68. 68. 73
  69. 69. Review1.What is the difference between weather and climate?2.What are the 4 basic elements of weather and climate that we measure? Which 2 are easiest to track?3.Name the 7 controls of weather and climate.4.What does “IPCC” stand for? What does it do?
  70. 70. Homework this week:Work on study guides (Ex. credit!) Draw and label the hypothetical radiationbalance diagram Read through class notes Highlight anything you don’t understand. Try to find the answer in the chapters. Ask for help if you still don’t get itReview the class slidesWatch a Khan Academy video