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Air: Climate and Pollution

Air: Climate and Pollution

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Air: Climate and Pollution

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  1. Air: Climate and Pollution Chapter 9, pp. 201-229

  2. Objectives • Factors that influence climate • Types and sources of air pollution • Air pollution and climate • Ways to reduce air pollution

  3. Weather

  4. Jan Jan Feb Feb Mar Mar Apr Apr May May Jun Jun Jul Jul Aug Aug Sep Sep Oct Oct Nov Nov Dec Dec Year Year °C mm 12.2 16.2 15.0 12.6 18.0 7.7 22.0 2.7 25.9 1.3 30.6 0.2 33.6 2.6 32.9 7.3 29.7 7.7 23.8 5.1 6.4 17.1 12.7 13.0 82.8 22.8 inches °F 54.0 0.6 59.0 0.5 64.4 0.3 71.6 0.1 78.6 0.1 87.1 0.0 92.5 0.1 91.2 0.3 85.5 0.3 74.8 0.2 0.3 62.8 0.5 55.4 3.3 73.0 Climate

  5. What influences the weather and climate? • The sun

  6. Seasons

  7. Milankovitch cycles • Shape of earth’s orbit: 100,000 years • Axis changes angle of tilt: 40,000 years • Axis wobbles: 26,000 years

  8. Wind • Uneven heating • Warm air rises • Air moves from H to L pressure • Local scale

  9. Sea and land breezes • Water has high specific heat • Day: air over land warmer than water • Night: air over water warmer than land

  10. Santa Ana winds • H pressure system over Great Basin • Early spring and fall

  11. Global winds • Region with most sun year-round? • Earth spins eastward • Winds clockwise in N Hemisphere

  12. Jet stream over U.S. • Winds high in the atmosphere

  13. Rain • Water condenses as air cools • Occurs in areas of low pressure

  14. Sunspots • 11 year cycles • Droughts

  15. What influences the weather? • The sun • The atmosphere

  16. The atmosphere

  17. Atmospheric zones

  18. Troposphere • Depth: to 13-30 miles • Deeper over equator, air is cold and dense at poles • Convection currents • Where weather occurs

  19. Stratosphere • Depth: 30-80 miles • 1000x more ozone (O3) than troposphere • Absorbs solar radiation • Very calm

  20. Greenhouse effect • Greenhouse gases • Keeps surface 36˚ warmer

  21. Methane ‘burps’ • Natural event • Raised temperatures • Responsible for mass extinctions?

  22. What influences the weather? • The sun • The atmosphere • The ocean

  23. Ocean currents • Caused by: • Surface wind • Density (colder, saltier water denser) • Thermohaline ocean conveyor

  24. Disruption of thermohaline conveyor • Lake Agassiz • 11,000 years ago • Stopped conveyor • Ice age

  25. El Niño/La Niña • El Nino Southern Oscillation (ENSO) • Natural phenomenon • 2-7 year intervals

  26. Effects of ENSO • Jet stream moves farther south • Lots of rain in CA and Midwest • Dry, warm weather in Pacific Northwest • Dry, warm weather in Indonesia and Australia

  27. What influences the weather? • The sun • The atmosphere • The ocean • The land

  28. Albedo • Definition • Lowest: dark, lots of absorption • Highest: light, lots of reflection

  29. Rain shadow effect

  30. What influences the weather? • The sun • The atmosphere • The ocean • The land • Air pollution

  31. More rain on weekends? • East coast: weekends rainy (Nature) • South: weekdays rainy (Journal of Geophysical Research) • Particulate matter from pollutants ‘seed’ clouds

  32. Anthropogenic changes • Ozone depletion • Global warming/climate change • ENSO changes • Ocean currents disrupted

  33. Air pollutants • Primary vs. secondary • Point source vs. non-point (fugitive) source

  34. The major pollutants

  35. Long-range transport

  36. Ozone depletion • Importance of O3? • Cause of depletion?: CFCs

  37. Ozone hole • Largest: Sept. 2006 • Photochemical reaction • No light for 3 months during winter

  38. Photochemical reactions

  39. Effects of UV radiation • Skin cancer (UVB), collagen damage, cataracts • Phytoplankton, plant damage

  40. Montreal Protocol • 1987 • Purpose? • Success? • 2006: largest • 2007: shrinking

  41. Climate change/global warming • Greenhouse gases released • CO2 • CH4 • N2O • CFCs • Intensify greenhouse effect

  42. I.P.C.C. • UN committee • Est. 1988 • Review published studies on climate • 800 scientists • 130 countries • http://www.ipcc.ch/

  43. The evidence…

  44. Rising temperatures

  45. Melting Arctic ice