Earth's Climate

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  • the greater the tilt, the greater the temperature difference is between summer and winter
  • this wobble affects the amount and intensity of solar energy that is received by the northern and southern hemispheres at different times of the year. This variation determines whether the two hemispheres have similar contrasts between seasons, or whether one hemisphere has greater temperature differences between seasons than the other hemisphere does.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • Earth's Climate

    1. 1. Earth’s Climate
    2. 2. Weather vs. Climate <ul><li>Weather = the environmental conditions that occur at a particular place at a particular time </li></ul>
    3. 3. Toronto Weather Forecast
    4. 4. Weather vs. Climate <ul><li>Climate = the average weather conditions that occur in a region over a long period of time (usually a minimum of 30 years ) </li></ul>
    5. 5. <ul><li>The climate of an area is affected by four main factors… </li></ul>
    6. 6. <ul><li>1.) Latitude </li></ul>
    7. 7. <ul><li>2.) Elevation </li></ul>
    8. 8. <ul><li>3.) Air masses </li></ul>
    9. 9. <ul><li>4.) Nearness to water </li></ul>
    10. 10. Terrestrial Biomes
    11. 15. Toronto’s Climate
    12. 16. Weather vs. Climate <ul><li>Weather </li></ul><ul><li>short-term (a few days) </li></ul><ul><li>immediate </li></ul><ul><li>unpredictable </li></ul><ul><li>Climate </li></ul><ul><li>long-term </li></ul><ul><li>fairly predictable </li></ul>
    13. 17. <ul><li>Energy from the sun is the single most important factor that affects climate on Earth </li></ul>
    14. 18. <ul><li>Solar energy travels through space as light and heat </li></ul>
    15. 19. <ul><li>The intensity of the the energy that reaches Earth’s surface affects the temperature of the air , water and land on the planet. </li></ul>
    16. 20. <ul><li>This heat produces the winds , rain and other features of the climate . </li></ul>
    17. 21. <ul><li>The amount of solar energy that reaches Earth’s surface varies with changes in solar activity as well as Earth’s orbit around the sun. </li></ul>
    18. 22. <ul><li>Measurements of solar radiation show that irregular fluctuations occur in the amount of energy produced by the sun. </li></ul>
    19. 23. <ul><li>In addition, a more regular solar cycle (or sunspot cycle) occurs approximately every 11 years . These solar variations differ by about 0.1% </li></ul>Sunspot Cycles
    20. 24. <ul><li>Earth rotates (spins) once every 24 hours around its axis. </li></ul><ul><li>While continuously rotating on its axis, Earth orbits the sun once a year . </li></ul>Movement of Earth
    21. 25. <ul><li>The combination of Earth’s annual orbit around the Sun and its tilted axis produces our seasons </li></ul>Movement of Earth
    22. 26. <ul><li>Throughout Earth’s history, its orbit , tilt and rotation have varied slightly in repeating cycles </li></ul>Changes in Rotation, Orbit & Tilt <ul><li>These variations change the amount and location of solar radiation reaching Earth, which also produce changes in climate </li></ul>
    23. 27. <ul><li>However, these changes do not fully explain all of the recent changes that have been observed and measured using other evidence . </li></ul>Changes in Rotation, Orbit & Tilt
    24. 28. <ul><li>Due to the gravitational attraction of other planets, Earth’s orbit fluctuates slightly over a cycle of about 100,000 years . </li></ul>Eccentricity
    25. 29. <ul><li>The angle of Earth’s tilt on its axis changes by approximately 2.4 o over a period of 41,000 years. </li></ul>Tilt
    26. 30. <ul><li>Also, because the Earth is not a perfect sphere , it wobbles slightly as it rotates on its axis. </li></ul>Wobble
    27. 31. <ul><li>Recall that Earth’s atmosphere extends from Earth’s surface up to about 560 km into space. </li></ul>
    28. 32. <ul><li>The atmosphere is composed mainly of nitrogen (N 2 ), oxygen (O 2 ), water vapour (H 2 O), as well as very small concentrations of other gases </li></ul>
    29. 33. <ul><li>Earth’s atmosphere absorbs thermal energy from the Sun as well as thermal energy that is emitted by Earth’s surface . </li></ul><ul><li>This process, called the greenhouse effect , is a natural part of Earth’s climate system. </li></ul>Natural Greenhouse Effect
    30. 34. Natural Greenhouse Effect
    31. 35. <ul><li>Greenhouse Effect = the natural warming caused when gases in Earth’s atmosphere absorb thermal energy that is radiated by the Sun and Earth </li></ul>Natural Greenhouse Effect
    32. 36. <ul><li>This process helps keep Earth’s temperature fluctuations within a certain range . Without this process, most of the solar energy reaching Earth would radiate back into space . </li></ul>
    33. 37. <ul><li>Wind is the movement of air from an area of high pressure to an area of lower pressure. </li></ul>Wind
    34. 38. <ul><li>All winds begin as a result of uneven heating of Earth’s surface. This movement of air transfers thermal energy around the world from warm areas to cooler areas. </li></ul>Wind
    35. 39. <ul><li>This movement of air affects ocean currents and precipitation patterns. </li></ul>Wind
    36. 40. <ul><li>The movement of currents at the surface of the oceans is driven by winds blowing over the water. These air currents are known as prevailing winds . </li></ul>Wind
    37. 41. <ul><li>Winds also affect precipitation . </li></ul><ul><li>When air masses meet, one air mass usually rises over the other. </li></ul><ul><li>The rising air cools , and any water vapour in the air condenses to form precipitation. </li></ul>Wind
    38. 42. <ul><li>Winds also affect precipitation through jet streams </li></ul><ul><li>Jet streams are high-altitude winds that travel long distances at very high speeds . </li></ul>Wind
    39. 44. <ul><li>Oceans cover about 2/3 of Earth’s surface </li></ul><ul><li>Recall that all the water in its different forms on Earth composes the hydrosphere </li></ul><ul><li>Together with the atmosphere, the hydrosphere transfers heat from one part of the planet to another. </li></ul>Water
    40. 45. <ul><li>Oceans can hold much more heat than the atmosphere can, therefore oceans act as a heat reservoir that buffers temperature changes in the atmosphere. </li></ul>
    41. 46. <ul><li>Large bodies of water influence climate because water has a large specific heat capacity compared to other substances. </li></ul><ul><li>Specific heat capacity = the amount of heat required to raise the temperature of 1g of a substance by 1 o C . </li></ul>Water
    42. 47. <ul><li>As a result, the temperature of large bodies of water tends to change slowly and by small amounts. </li></ul><ul><li>The temperature of land masses changes more quickly and by larger amounts. </li></ul>Water
    43. 48. <ul><li>Because of their light colour , snow and ice reflect solar radiation. </li></ul><ul><li>The fraction of light or radiation that is reflected by a surface is called albedo . </li></ul>Ice and Snow
    44. 49. <ul><li>In general, light coloured surfaces reflect energy and dark surfaces absorb energy. </li></ul><ul><li>The ocean surface reflects about 7% of solar energy </li></ul><ul><li>By contrast, a snowy field can reflect as much as 80-90% of the solar energy that strikes it. </li></ul>Ice and Snow
    45. 50. Ice and Snow
    46. 51. Tectonic Activity Earth has about 12 major tectonic plates that move at a rate of a few centimeters each year. As a result, the shapes of the oceans and continents are always changing .
    47. 52. Tectonic Activity The changing distribution of land and water affects patterns of air and water circulation and the transfer of thermal energy around the world.
    48. 53. In addition, volcanic eruptions , (which generally occur at the boundaries of tectonic plates), spew ash and other particles called “ aerosols ” into the atmosphere.
    49. 54. Aerosols reflect solar radiation and have a cooling effect on the global climate.
    50. 55. This effect may last from a few years to several decades , until the particles are removed from the atmosphere by precipitation and settling .

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