The Atmosphere

1. The Atmosphere

2. Characteristics of the AtmosphereTerms: atmosphere, air pressure, troposphere, stratosphere, mesosphere, thermosphere

3. Describe the composition of Earth’s atmosphere. What does the name of each atmospheric layer mean? Why doesn’t the thermosphere feel hot? Characteristics of the Atmosphere

4. The Composition of the Atmosphere • The atmosphere is a mixture of gases that surrounds Earth. • Makes conditions on Earth suitable for living things • Gases keep the atmosphere on Earth’s surface warm enough for water to exist as a liquid, protects against dangerous radiation, prevents Earth’s surface from being hit by most meteoroids or chunks of rock from outer space. • Gases • Nitrogen 78% • Oxygen 21% • Other gases 1% • Water vapor <1% • Solids • Dust, volcanic ash, salt, dirt, smoke • Liquids • water

5. Atmospheric Pressure and Temperature • As altitude increases, air pressure decreases • Air pressure is strongest at Earth’s surface because more air is above you. • Atmospheric composition affects air temperature • Temperature differences result from the way solar energy is absorbed as it moves through the atmosphere • High % of gases that absorb solar energy= warmer • Less gases that absorb solar energy = cooler

6. Layers of the Atmosphere • Based on temperature changes: • Troposphere: layer in which we live; contains almost all of the weather, carbon dioxide, water vapor, clouds, air pollution, and life-forms • Stratosphere: gases are layered and don’t mix; contains the ozone layer; protects life by absorbing harmful UV radiation • Mesosphere: middle layer; the coldest layer; most meteoroids burn up here, producing meteoroid trails • Thermosphere: temperature increases; does not feel hot; outer most part of atmosphere; no definite outer limit

7. Summary • Nitrogen and oxygen make up most of Earth’s atmosphere. • Air pressure decreases as altitude increases. • The composition of atmospheric layers affects their temperature. • The troposphere is the lowest atmospheric layer. It is the layer in which we live. • The stratosphere contains the ozone layer, which protects us from harmful radiation. • The mesosphere is the coldest atmospheric layer. Meteoroids burn up in this layer. • The thermosphere is the uppermost layer of the atmosphere.

8. #1 Quick Check • Why does the temperature of different layers of the atmosphere vary? • Because air temperature increases as altitude increases • Because the amount of energy radiated from the sun varies • Because of interference by humans • Because of the composition of gases in each layer

9. #2 Quick Check What is the most abundant gas in the atmosphere? • oxygen • hydrogen • nitrogen • carbon dioxide

10. #3 Quick Check A major source of oxygen for the earth’s atmosphere is a. sea water. b. the sun. c. animals d. plants

11. #4 Quick Check The bottom layer of the atmosphere where almost all weather occurs, is the • stratosphere • troposphere • thermosphere • mesosphere

12. #5 Quick Check The ozone layer is located in the • stratosphere • troposphere • thermosphere • mesosphere

13. Atmospheric HeatingTerms: radiation, thermal conduction, convection, global warming, greenhouse effect

14. How do differences in air density cause convection currents? What is the radiation balance? What is the difference between the greenhouse effect and global warming? Atmospheric Heating

15. Energy in the Atmosphere • Radiation: Energy transfer by waves • Transfer of energy as electromagnetic waves • Conduction: Energy transfer by contact • Transfer of thermal (heat) energy through material • Convection: energy transfer by circulation • Transfer of thermal energy by circulation or movement of a gas or liquid.

16. Greenhouse Effect • Greenhouse effect and life on earth: process in which gases in the atmosphere, water vapor, carbon dioxide, absorb thermal energy and radiate it back to Earth. • Atmosphere acts as greenhouse effect because the gases function like the glass walls and roof of a greenhouse, allowing solar energy to enter but prevents thermal energy from escaping. • The amount of energy Earth receives everyday from the sun is balance by the amount of energy Earth reradiates into space.

17. Greenhouse Gases and Global Warming • Global warming is the gradual increase in average global temperature. • Human activity, such as burning of fossil fuels, and deforestation, may be increasing the levels of greenhouse gases, such as carbon dioxide, in the atmosphere. • If global temperatures continue to rise, it could disrupt global climate patterns

18. Summary • Energy from the sun is transferred through the atmosphere by radiation, thermal conduction, and convection. • Radiation is energy transfer by electromagnetic waves. Thermal conduction is energy transfer by direct contact. Convection is energy transfer by circulation or movement of a gas or liquid. • The greenhouse effect is Earth’s natural heating process. Increasing levels of greenhouse gases could cause global warming.

19. #1 Quick Check Which of the following is the best example of thermal conduction? • A light bulb warming a lampshade • An egg cooking in a frying pan • Sitting by a fireplace getting warm by the fire • Gases circulating in the atmosphere

20. #2 Quick Check What percentage of the solar energy that reaches the outer atmosphere is absorbed at the Earth’s surface? • 20% • 30% • 50% • 70%

21. #3 Quick Check By which method does most thermal energy in the atmosphere circulate? • conduction • convection • advection • radiation

22. #4 Quick Check The balance between incoming and outgoing energy is called • The convection balance. • The conduction balance. • The greenhouse effect. • The radiation balance.

23. #5 Quick Check As the sun heats the surface of the ocean, some of the water evaporates and enters the air. How does water vapor move in the atmosphere? • by waves • by clouds • by conduction • by convection

24. #6 Quick Check Energy transferred as electromagnetic waves is called • thermal conduction. • convection. • radiation. • convection current.

25. #7 Quick Check The process by which gases in the atmosphere absorb thermal energy and radiate it back to earth is called • the thermal effect. • global warming • the greenhouse effect. • radiation balance.

26. Global Winds and Local Winds Terms: wind, Coriolis effect, polar easterlies, westerlies, trade winds, jet stream

27. What causes wind? Why does sinking air cause areas of high pressure? Would there be winds if the Earth’s surface were the same temperature everywhere? Explain your answer. Global Winds and Local Winds

28. Why Air Moves • Wind is caused by differences in air pressure. • The greater the pressure difference, the faster the wind moves. • Air rises at the equator and Sinks at the poles • Pressure belts are found every 30° • The Coriolis effect is the apparent curving of the path of a moving object from an otherwise straight path due to the Earth’s rotation.

29. Global Winds • Polar Easterlies: extend from the poles to 60° latitude in both hemisphere; moves from the poles carrying cold, sinking arctic air; can carry moist air, producing snow and freezing weather. • Westerlies: found between 30° and 60° latitudes; flow towards the poles west to east; can carry moist air producing rain and snow. • Trade Winds: extends from 30° to the equator; Early traders used trade winds to travel from Europe to America;

30. Global Winds • The Doldrums: where the trade winds from the Northern and Southern Hemispheres meet in an area around the equator; very little wind • The Horse Latitudes: At 30° North and South; weak winds;sinking air is very dry; name due to horses thrown overboard to save drinking water. • Jet Streams: a narrow belt of strong winds that blow in the upper troposphere; pilots use the jet stream to take advantage of the wind moving west to east.

31. Local Winds • Local winds are produced by local geographic features. • Local winds move short distances and can blow from any direction. • Local winds include sea and land breezes and mountain and valley breezes

32. Sea and Land breezes • During the day, air over the ocean is cooler and forms an area of high pressure. The cool air flows to the land, producing a land breeze. • Air over the land is warmer. As warm air rises, it creates an area of low pressure. • At night, air over the ocean is warmer. As the warm air rises, it forms an area of low pressure. • Air over land is cooler and forms an area of high pressure. The cool air moves toward the ocean, producing a land breeze.

33. Summary • Winds blow from areas of high pressure to areas of low pressure. • Pressure belts are found approximately every 30° of latitude. • The Coriolis effect causes wind to appear to curve as it moves across the Earth’s surface. • Global winds include the polar easterlies, the westerlies, and the trade winds. • Local winds include sea and land breezes and mountain and valley breezes.

34. #1 Quick Check • Why does warm air rise and cold air sink? • because warm air is less dense than cold air • because warm air is more dense than cold air • because cold air is less dense than warm air • because warm air more pressure than cold air

35. #2 Quick Check In which wind belt is most of the United States located? • westerlies • northeast trade winds • southeast trade winds • doldrums

36. #3 Quick Check What causes wind? • differences in air pressure • differences in gravity • differences in oxygen • differences in the thermosphere

37. #4 Quick Check What causes differences in air pressure around the Earth? A. Warm air rises at the equator, and cold air sinks at the poles B. Warm air sinks at the equator, and cold air rises at the poles C. Warm air rises at the equator, and cold air rises at the poles. D. Cold air rises at the equator, and warm air sinks at the poles.

38. #5 Quick Check Air moves in large, circular patterns called • pressure belts. • convection currents. • convection cells. • trade winds.

39. #6 Quick Check Narrow belts of winds that can reach 400 km/h are called A, jet currents. b. jet streams. C. convection currents. D. convection streams.

40. Air Pollution Terms: air pollution, acid precipitation

41. Primary Pollutants • Primary pollutants are pollutants that are put directly into the air by humans or natural activity. • Natural sources: dust, sea salt, volcanic gases and ash, smole from forest fires, pollen. • Human sources: carbon monoxide, dust, smoke, chemicals from paint .

42. Secondary Pollutants • Pollutants that form when primary pollutants react with other primary pollutants • Ozone • Smog

43. Sources of Human Caused Air Pollution • A major source of air pollution is from transportation • Industrial Air Pollution – fossil fuels, oil refineries, chemical manufacturing plants, dry-cleaning busineses, furniture refinishers, auto body shops • Indoor Air Pollution - Nitrogen oxides, Fungi and bacteria, Carbon monoxide, Solvents, Gasoline, Chlorine and ammonia, chemicals

44. Acid Precipitation • Precipitation such as rain, sleet, snow, hail, that contains acids from air pollution • Effects of Acid precipitation on plants • Effects of Acid precipitation on forests • Acid precipitation and Aquatic ecosystems

45. The Ozone Hole • The ozone layer is thinning • Caused by chemicals called CFCs • Not able to block the sun’s harmful UV rays • Damages genes • Can cause skin cancer • Cooperation to reduce the ozone hole • CFCs can remain active 60 -120 years • Will take many years for the ozone layer to completely recover

46. Air Pollution and Human Health • Daily exposure to small amounts of air pollution can cause serious health problems: • Children, elderly people • People with asth ma • allergies. • Lung problems • Heart problems • Coughing • Headaches • Lung cancer

47. Cleaning Up Air Pollution • Much progress has been made with cleaning up air pollution • Clean Air Act 1970 • EPA – Environmental Protection Agency • Controlling Air Pollution from Industry • Allowance trading System- established amount of pollutants that companies can release • Reducing Aair Pollution from Vehicles • Hybrids, carpooling, public transportation, bikes, walking

48. Quick Check 1. What are some sources of indoor pollution? 2. What is the ozone hole, and why does it form? 3. What are some effects of air pollution on human health? 4. What are some major sources of outside air pollution? 5. What are some ways to reduce air pollution?