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Podcast 20.1 THE ATMOSPHERE

Podcast 20.1 THE ATMOSPHERE. Layers and characteristics of the atmosphere. 20.1 Objectives. Identify the Primary Layers of the Atmosphere Discuss characteristics of each layer and some of the unique layers of the atmosphere.

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Podcast 20.1 THE ATMOSPHERE

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  1. Podcast 20.1THE ATMOSPHERE Layers and characteristics of the atmosphere

  2. 20.1 Objectives • Identify the Primary Layers of the Atmosphere • Discuss characteristics of each layer and some of the unique layers of the atmosphere

  3. I expect you to know how to convert between miles and kilometers

  4. Conversion Rules • To convert miles to kilometers • multiply by 1.6 km 1 mi • It’s 17 miles from Monte Vista to Alamosa, how many kilometers is this? • To convert kilometers to miles • multiply by 1 mi 1.6 km • The atmosphere is 480 kilometers, how many miles is this?

  5. The Atmosphere • The atmosphere is a layer of gases surrounding the earth • It is held by gravity • The main two gases in the atmosphere are Nitrogen (78%) and Oxygen (21%) • What percent is left for all other gases?

  6. Know these • The layers are defined by temperature changes

  7. Troposphere • The lowest layer, densest • Where we live • Clouds, rain, wind, and snow occur mostly in the troposphere • Is warmed by the solar energy that was absorbed by the ground and oceans • Radiation and conduction

  8. Remember Radiation and Conduction? • Radiation is the transfer of energy by waves • Stand next to a fire, and you feel the heat by radiation • Conduction is energy transferred by contact of particles • Put your hand on a hot object and the heat is conducted into your hand

  9. Sun’s radiation

  10. Temperature in the Troposphere • The temperature in the Troposphere gets colder at higher altitudes for two reasons • You are farther away from the heat source and the atmosphere is less dense and cannot conduct as much heat • Temperature decreases 6 degrees C for every 1 kilometer

  11. The Troposphere is where the weather occurs • All the clouds • Rain, snow, sleet… • We’ll see weather in another podcast

  12. Temperature Inversions • Sometimes cool air gets trapped beneath warm air • This often occurs in places surrounded by mountains • The San Luis Valley in winter, traps the coldest air in the lowest part of the valley • The temperature can change 30 degrees F in the drive from Monte Vista to Alamosa

  13. That’s why we can be so much colder than everyone else

  14. Temperature inversions trap pollution • Large cities next to mountains can have temperature inversions • Temperature inversions can happen in the summer • When the cool polluted air cannot escape into the atmosphere, it stays next to the surface of the ground

  15. Smog • The pollution doesn’t stop, so more pollution is added to the already polluted air • As more pollution is added to the layer, it becomes a layer of smog over the city • This air is toxic, and unhealthy to breathe • Both Los Angeles and Denver can have temperature inversions

  16. The Tropopause • the upper boundary of the troposphere • It is where the temperature stops decreasing • It is lower at the poles 4-8 km and higher near the equator 10- 18 km • Convert these values to miles

  17. The Stratosphere • The next layer of the atmosphere doesn’t contain much oxygen or water vapor • Few clouds form in the stratosphere • Temperature in the stratosphere is a constant –55 degrees C up to 25 kilometers • Temperature in the upper stratosphere gets warmer

  18. Why does the Stratosphere get warmer? • Because of the ozone layer • Ozone absorbs solar radiation • Ozone shields earth from much of the ultraviolet radiation • Damage to the ozone layer threatens life on earth • Areas where the ozone layer is weak or has holes allow damaging UV rays in, increasing skin cancer rates in those areas (Australia)

  19. Temperature changes in the Atmosphere

  20. Ozone Layer • Within the top of Stratosphere • 90% of earth’s Ozone • Being damaged by aerosols

  21. The Concorde • The Concorde could fly at altitudes of 60,000 feet – • How many miles is that? • How many kilometers? • What layer of the atmosphere did the Concorde flying in?

  22. The Concorde • In service from 1976 to 2005 • One (and only) crash in 2000 – killed everyone on board • Only 20 ever built • COSTLY

  23. The Mesosphere • From 50-80 kilometers above earth • Temperatures fall in the mesosphere • Upper mesosphere is – 80 degrees Celsius, the coldest temperature in the atmosphere

  24. Another Temperature Change in the Atmosphere

  25. The Thermosphere • The outer layer of the atmosphere extends from 80 to 480 kilometers • The thermosphere is the least dense layer of the atmosphere, but it is very hot because it is subjected to intense solar radiation • Temperatures reach 980 degrees Celsius

  26. The Exosphere • The outer edge of the atmosphere • Cannot hold all of its gases • Some gas escapes to space • Other gases in space are captured and added to earth’s atmosphere

  27. The Ionosphere • In the lower thermosphere and upper mesosphere energy is absorbed from the sun • Electrically charged ions form • This region is sometimes called the ionosphere • It is this area of the atmosphere that allows radio waves to travel long distances

  28. Radio uses the Ionosphere • If radio waves couldn’t bounce off the ionosphere, we would only be able to hear radio waves close to the signal • Radio waves bounce off the ionosphere and travel back to earth

  29. Radio travels farther at night • The ionosphere does not stay in the same place • At night, when there is not solar radiation, the ionosphere moves higher • Radio waves bouncing off a higher ionosphere can travel farther away from the source • Short wave radio operators can pick up signals from as far away as Russia at night

  30. The Auroras • The ionosphere is also the layer that can light up at the north and south poles • The northern aurora is called the aurora borealis and the southern aurora is called the aurora australis

  31. Northern Lights

  32. End Podcast 20.1 Know your objectives!

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