Atmosphere and Climate Change

1. Environmental Science Atmosphere and Climate Change

2. I. Definitions • A. Weather = state of the atmosphere at a particular place at a particular moment

3. B. Climate = the long-term prevailing weather conditions at a particular place based upon records taken

4. II. Factors that determine climate • A. Latitude – the distance from the equator measured in degrees north or south • 1. the most important factor determining climate • 2. the amount of solar energy an area of Earth receives depends on its latitude

5. 3. Low Latitudes • A. More sun falls on this area than others • B. Night and day are both about 12 hours long throughout the year • C. Temperatures are high throughout the year • D. No distinct summer or winter

7. 4. High Latitudes – regions closer to the poles • A. Sun is lower in the sky • B. Sunlight hits Earth at an oblique angle and spreads over a larger surface area than at the equator • C. Yearly average temperatures near the poles are lower than at the equator

8. d. Hours of daylight vary • 1. 45 degrees north and south latitude, there is 16 hours of daylight during the summer and 8 hours of sunlight during the winter • 2. near the poles, sun sets for only a few hours each day in summer and rises for only a few hours during the winter • 3. Creates a large yearly temperature range

9. B. Atmospheric Circulation • 1. Three important properties of air illustrate how air circulation affects climate • A. Cold air sinks because it is denser than warm air • 1. as it sinks, it compresses and warms

10. B. Warm air rises • 1. it expands and cools as it rises • C. Warm air can hold more water vapor than cold air • 1. when warm air cools, the water vapor it contains may condense into liquid and form rain, snow or fog

11. 2. Solar energy heats the ground which warms the air above it • 3. warm air rise and cooler air moves in to replace it • 4. Wind = the movement of air within the atmosphere created by the above (#2 and 3)

12. 5. pattern of global atmospheric circulation results because Earth rotates and because different latitudes receive different amounts of solar energy • A. Circulation pattern determines Earth’s precipitation pattern

14. 6. Global circulation patterns • A. Cool normally sinks • 1. over equator cool air cannot descend because hot air is rising below the cool air • 2. the cool air is forced away from the equator and toward the poles

15. B. At 30 degrees N and S latitudes air begins to accumulate in the upper atmosphere • 1. some of the air sinks back to the Earth’s surface and becomes warmer as it descends

16. 2. warm, dry air moves across the surface causing water to evaporate from land below • 3. Descending air either moves toward the equator or flows toward the poles • A. Air moving toward the poles warms while it is near Earth’s surface

17. C. At 60 degrees N and S latitude, this warmed air collides with cold air traveling from the poles • 1. the warm air rises • 2. a small part of this rising air returns back to the circulation pattern between 60 and 30 degrees north and south latitudes

18. 3. Most of the uplifted air is forced toward the poles • A. Cold, dry air descends at poles (very cold desert)

19. 7. Prevailing Winds • Winds that blow predominately in one direction throughout the year • A. Do not blow directly northward or southward

20. 1. Because of the rotation of the Earth • A. Winds are deflected to right in Northern Hemisphere • B. Winds are deflected to left in Southern Hemisphere

21. B. Trade winds – belts of prevailing winds in both hemispheres between 30 degrees north and south • 1. blow from northeast in Northern Hemisphere • 2. blow from southeast in Southern Hemisphere

22. C. Westerlies – prevailing winds produced between 30 and 60 degrees north and south latitudes • 1. blow southwest in the Northern Hemisphere • 2. blow northwest in the Southern Hemisphere

23. D. Polar easterlies • blow from the poles to 60 degrees north and south latitude

24. C. Oceanic Circulation Patterns • 1. surface ocean currents have a great effect on climate because water holds large amount of heat • A. Movement of surface ocean currents is caused by winds and the rotation of the Earth • B. Surface currents redistribute warm and cool masses of water around the planet

25. C. Some surface currents warm or cool coastal areas year round • D. Affect the climate in many parts of the world

26. 2. El Nino – Southern Oscillation • - the short term (6-18 month period) periodic change in the location of warm and cools water masses in the Pacific Ocean

27. A. Winds in the western Pacific which are usually weak, strengthen and push warm water eastward

28. B. Rainfall follows and produces increased rainfall in southern US and in equatorial South America • C. Causes drought in Indonesia and Australia

29. d. La Nina – the water in the eastern Pacific is cooler than usual • E. El Nino and La Nina are opposite phases of the El Nino-Southern Oscillation (ENSO) cycle • 1. El Nino is the warm phase • 2. La Nina is the cool phase

30. 3. Pacific Decadal Oscillation • - a long-term (20-30 years) change in the location of warm and cold water masses in the Pacific

31. A. PDO influences the climate in the northern Pacific Ocean and North America • B. Affects ocean surface temperatures, air temperatures, and precipitation patterns

32. D. Topography • 1. Elevation – height above sea level • A. Temperatures fall about 11 degrees for every 1,000 m increase in elevation

33. 2. Mountains and ranges also influence the distribution of precipitation • A. Rain shadow – one side of the mountain gets rain from the ocean air while the opposite side receives dry air

34. E. Other Influences • 1. Solar maximum – the sun emits an increased amount of UV radiation

35. A. UV radiation produces more ozone • B. The increase in ozone warms the atmosphere • C. Increased solar radiation can also warm the lower atmosphere and surface of the Earth

36. 2. Volcanic eruptions – cause sulfur dioxide gas to reach the upper atmosphere • A. The sulfur dioxide can remain in the atmosphere for up the 3 years • B. Reacts with smaller amounts of water vapor and dust in the atmosphere

37. C. This reaction forms a bright layer of haze that reflects enough sunlight to cause the global temperature to decrease

38. III. The Ozone Shield • A. Ozone layer – an area in the stratosphere where ozone is highly concentrated • 1. ozone – molecule made of three oxygen molecules • 2. ozone layer absorbs most of the ultraviolet (UV) light from the sun • A. UV light can damage genetic material in living organisms

39. B. Ozone Depletion • 1. chloroflourocarbons (CFCs) – class of human-made chemicals; can damage ozone • A. Non-poisonous, nonflammable, and non-corrosive to metals • B. Used as coolants in refrigerators and air conditioners, in making plastic foams, and as propellants in spray cans

40. C. Are chemically stable at Earth’s surface • D. Break apart in stratosphere and absorb UV radiation which destroys ozone • 1. each CF molecule contains one – four chlorine atoms • 2. a single chlorine atom can destroy 1,000,000 ozone molecules

41. 2. ozone hole – a thinning of stratospheric ozone that occurs over the poles during the spring • A. First reported in 1985 above the South Pole • 1. ozone had thinned 50-98%

42. B. NASA went back and looked at data from 1979 and discovered the first signs of zone thinning • C. Ozone thinning is also occurring over the Artic • D. in 1997, ozone levels over part of Canada were 45% below normal

43. 3. How ozone holes form • A. Polar vortex – strong circulating winds over Antarctica during winter • 1. isolates cold air from surrounding warmer air • 2. air inside vortex grows extremely cold and fall below -80 degrees C

44. 3. form polar stratospheric clouds – high altitude clouds made of water and nitric acid • B. On surface of polar stratospheric clouds, the products of CFCs are changed to chlorine

45. 1. when sunlight returns in spring, chlorine is split into two chlorine atoms by UV rays • 2. chlorine atoms rapidly destroy ozone

46. 3. destruction of ozone causes a thin spot or ozone hole that lasts several months • A. Some estimate that 70% of ozone layer can be destroyed during this time

47. C. Ozone produced as air pollution does not repair the ozone hole • 1. ozone produced by pollution breaks down or combines with other substances in troposphere before it can reach the stratosphere

48. 4. Effects of ozone thinning on humans • A. More UV light reaches Earth’s surface which damages DNA • B. Makes body more susceptible to skin cancer • C. May cause other damaging effects to human body

49. 5. Effects of ozone thinning on plants and animals • A. Higher UV light can kill phytoplankton • 1. disrupts ocean food chains • 2. increases amount of CO2 in atmosphere

50. B. Higher UV light is damaging to amphibians • 1. kills eggs which do not have shells • 2. amphibians are indicator species –species used to indicate environmental changes