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Chapter 17

Chapter 17. The Atmosphere: Structure and Temperature. Learning Objectives. 17.1 Atmosphere Characteristics. Compare and Contrast Weather vs. Climate Explain why seasonal changes occur. California State Standards. 17.1 Atmosphere Characteristics.

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Chapter 17

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  1. Chapter17 The Atmosphere: Structure and Temperature

  2. Learning Objectives 17.1 Atmosphere Characteristics • Compare and Contrast • Weather vs. Climate • Explain why seasonal changes occur

  3. California State Standards 17.1 Atmosphere Characteristics 6(a) – Weather (in the short run) and climate (in the long run) involves the transfer of energy into and out of the atmosphere. 8(a) – The thermal structure and chemical composition of the atmosphere 8(c) – The location of the ozone layer in the upper atmosphere, its role in absorbing ultraviolet radiation, and the way in which this layer varies both naturally and in response to human activities.

  4. 17.1 Atmosphere Characteristics • Weather is constantly changing, and it refers to the state of the atmosphere at any given time and place. • Climate, however, is based on observations of weather that have been collected over many years. • Climate helps describe a place or region.

  5. Checking for Understanding 17.1 Atmosphere Characteristics Take 2 minutes – partner on your LEFT, Decide what the major differences are between weather and climate: Weather is … Climate is …. Write the answer on your notes

  6. Composition of the Atmosphere 17.1 Atmosphere Characteristics  Major Components • Air is a mixture of different gases and particles, each with its own physical properties.

  7. Volume of Clean, Dry Air What 2 elements make up 99% of our atmosphere? Oxygen Nitrogen Remaining 1% is Argon (inert gas) .039 percent is CO2

  8. Composition of the Atmosphere 17.1 Atmosphere Characteristics  Variable Components • Water vapor is the source of all clouds and precipitation. Like carbon dioxide, water vapor absorbs heat given off by Earth. It also absorbs some solar energy. • Ozone is a form of oxygen that combines three oxygen atoms into each molecule (O3). • If ozone did not filter most UV radiation and all of the sun’s UV rays reached the surface of Earth, our planet would be uninhabitable for many living organisms.

  9. Composition of the Atmosphere 17.1 Atmosphere Characteristics  Human Influence • Emissions from transportation vehicles account for nearly half the primary pollutants by weight.

  10. Primary Pollutants

  11. Height and Structure of the Atmosphere 17.1 Atmosphere Characteristics  The atmosphere rapidly thins as you travel away from Earth until there are too few gas molecules to detect.  Pressure Changes • Atmospheric pressure is simply the weight of the air above.

  12. Atmospheric Pressure vs. Altitude

  13. Height and Structure of the Atmosphere 17.1 Atmosphere Characteristics  Temperature Changes • The atmosphere can be divided vertically into four layers based on temperature. • Thetroposphereis the bottom layer of the atmosphere where temperature decreases with an increase in altitude. • Thestratosphereis the layer of the atmosphere where temperature remains constant to a height of about 20 kilometers. It then begins a gradual increase until the stratopause.

  14. Snowy Mountaintops Contrast with Warmer Snow-Free Lowlands

  15. Height and Structure of the Atmosphere 17.1 Atmosphere Characteristics  Temperature Changes • The mesosphere is the layer of the atmosphere immediately above the stratosphere and is characterized by decreasing temperatures with height. • Thethermosphere is the region of the atmosphere immediately above the mesosphere and is characterized by increasing temperatures due to the absorption of very short-wave solar energy by oxygen.

  16. Thermal Structure of the Atmosphere

  17. Earth-Sun Relationships 17.1 Atmosphere Characteristics  Earth’s Motions • Earth has two principal motions—rotation and revolution.  Earth’s Orientation • Seasonal changes occur because Earth’s position relative to the sun continually changes as it travels along its orbit.

  18. Checking for Understanding 17.1 Atmosphere Characteristics Take 2 minutes – partner on your RIGHT, Decide WHY seasonal changes occur … Seasonal changes occur because … Write the answer in your Science Journal

  19. Tilt of Earth’s Axis

  20. Earth-Sun Relationships 17.1 Atmosphere Characteristics  Solstices and Equinoxes • The summer solsticeis the solstice that occurs on June 21 or 22 in the Northern Hemisphere and is the “official” first day of summer. • Thewinter solsticeis the solstice that occurs on December 21 or 22 in the Northern Hemisphere and is the “official” first day of winter.

  21. Earth-Sun Relationships 17.1 Atmosphere Characteristics  Solstices and Equinoxes • The autumnal equinox is the equinox that occurs on September 22 or 23 in the Northern Hemisphere. • The spring equinox is the equinox that occurs on March 21 or 22 in the Northern Hemisphere.

  22. Length of Daylight 17.1 Atmosphere Characteristics  The length of daylight compared to the length of darkness also is determined by Earth’s position in orbit.

  23. Solstices and Equinoxes

  24. Learning Objectives 17.2 Heating the Atmosphere • Explain how heat and temperature are related • List the 3 major mechanisms of heat transfer • Describe how the atmosphere is affected by heat transfer mechanisms

  25. California State Standards 17.2 Heating the Atmosphere 4(b) – The fate of incoming solar radiation in terms of reflection, absorption, and photosynthesis. 5(a) - How differential heating of Earth results in circulation patterns in the atmosphere and oceans that globally distribute the heat. 6(a) – Weather (in the short run) and climate (in the long run) involves the transfer of energy into and out of the atmosphere.

  26. Energy Transfer as Heat 17.2 Heating the Atmosphere  Heat is the energy transferred from one object to another because of a difference in the objects’ temperature.  Temperature is a measure of the average kinetic energy of the individual atoms or molecules in a substance.

  27. Checking for Understanding 17.2 Heating the Atmosphere Take 2 minutes – partner BEHIND YOU/IN FRONT OF YOU, Decide: What are the differences between Heat and Temperature … Heat is … Temperature is … Write the answer in your Science Journal

  28. Energy Transfer as Heat 17.2 Heating the Atmosphere  Three mechanisms of energy transfer as heat are conduction, convection, and radiation.  Conduction • Conduction is the transfer of heat through matter by molecular activity.  Convection • Convection is the transfer of heat by mass movement or circulation within a substance.

  29. Checking for Understanding 17.2 Heating the Atmosphere Take 2 minutes – by yourself, Decide: What are the three mechanisms of energy transfer as heat? Explain in your own words. C. C. R. Write the answer in your Science Journal

  30. Energy Transfer as Heat

  31. Energy Transfer as Heat 17.2 Heating the Atmosphere  Electromagnetic Waves • The sun emits light and heat as well as the ultraviolet rays that cause a suntan. These forms of energy are only part of a large array of energy emitted by the sun, called the electromagnetic spectrum.

  32. Electromagnetic Spectrum

  33. Visible Light Consists of an Array of Colors

  34. Energy Transfer as Heat 17.2 Heating the Atmosphere  Radiation • Radiation is the transfer of energy (heat) through space by electromagnetic waves that travel out in all directions. • Unlike conduction and convection, which need material to travel through, radiant energy can travel through the vacuum of space.

  35. Energy Transfer as Heat 17.2 Heating the Atmosphere  Radiation • All objects, at any temperature, emit radiant energy. • Hotter objects radiate more total energy per unit area than colder objects do. • The hottest radiating bodies produce the shortest wavelengths of maximum radiation. • Objects that are good absorbers of radiation are good emitters as well.

  36. What Happens to Solar Radiation? 17.2 Heating the Atmosphere  When radiation strikes an object, there usually are three different results. 1. Some energy is absorbed by the object. 2. Substances such as water and air are transparent to certain wavelengths of radiation. 3. Some radiation may bounce off the object without being absorbed or transmitted.

  37. Solar Radiation

  38. What Happens to Solar Radiation? 17.2 Heating the Atmosphere  Reflection and Scattering • Reflection occurs when light bounces off an object. Reflection radiation has the same intensity as incident radiation. • Scattering produces a larger number of weaker rays that travel in different directions.

  39. What Happens to Solar Radiation? 17.2 Heating the Atmosphere  Absorption • About 50 percent of the solar energy that strikes the top of the atmosphere reaches Earth’s surface and is absorbed. • The greenhouse effect is the heating of Earth’s surface and atmosphere from solar radiation being absorbed and emitted by the atmosphere, mainly by water vapor and carbon dioxide.

  40. Checking for Understanding 17.2 Heating the Atmosphere Take 2 minutes – with your table, Decide: How does convection, conduction and radiation affect the Earth’s atmosphere? . . . Write the answer in your Science Journal

  41. Learning Objectives 17.3 Temperature Controls  Explain what a temperature control is.  Compare and contrast the heating of land and water.  Explain why some clouds reflect a portion of sunlight back into space.

  42. California State Standards 17.3 Temperature Controls 4(b) – The fate of incoming solar radiation in terms of reflection, absorption, and photosynthesis. 4(c) - The different atmospheric gases that absorb the Earth’s thermal radiation and the mechanism and significance of the greenhouse effect. 5(a) - How differential heating of Earth results in circulation patterns in the atmosphere and oceans that globally distribute the heat. 8(c) - The location of the ozone layer in the upper atmosphere, its role in absorbing ultraviolet radiation, and the way in which this layer varies both naturally and in response to human activities.

  43. Why Temperatures Vary 17.3 Temperature Controls • Temperature Control – any factor that causes temperature to vary from place to place and time to time • Factors other than latitude that exert a strong influence on temperature include heating of land and water, altitude, geographic position, cloud cover, and ocean currents.

  44. Checking for Understanding 17.3 Temperature Controls Take 2 minutes – person on your LEFT, Decide: What is a temperature control? . Write the answer in your Science Journal

  45. Why Temperatures Vary 17.3 Temperature Controls  Land and Water • Land heats more rapidly and to higher temperatures than water. Land also cools more rapidly and to lower temperatures than water.

  46. Checking for Understanding 17.3 Temperature Controls Take 2 minutes – person on your RIGHT, Decide: Compare / Contrast heating of land and water? Land heats . . . Water heats . . . Write the answer in your Science Journal

  47. Mean Monthly Temperatures for Vancouver and Winnipeg

  48. Why Temperatures Vary 17.3 Temperature Controls  Geographic Position • The geographic setting can greatly influence temperatures experienced at a specific location. • Winds – Coastal or leeward • Mountains – act as barrier

  49. Mean Monthly Temperatures for Eureka and New York City

  50. Mean Monthly Temperatures for Seattle and Spokane

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