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Chapter One: The Atmosphere

Chapter One: The Atmosphere

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Chapter One: The Atmosphere

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  1. Chapter One: The Atmosphere Weather

  2. Section 1: Characteristics of the Atmosphere • Composition of the atmosphere: • made mostly of nitrogen and oxygen • 21% oxygen, 78% nitrogen • Remaining 1% made up of: argon, carbon dioxide, water vapor, and other gases

  3. Atmospheric Pressure and Temperature • Atmosphere is held around Earth by gravity • Air pressure is strongest at Earth’s surface because more air is above you • As altitude increases air pressure decreases • Air temperature changes as altitude increases • Some parts are warmer because they contain a high % o gases that absorb solar energy • Other parts contain less of these gases and are cooler

  4. Layers of the Atmosphere • Thermosphere: the edge of the atmosphere • Mesosphere: the middle layer • Stratosphere: the home of the ozone layer • Troposphere: the layer in which we live • Look at figure 3 page 6

  5. Troposphere: • Densest layer • Contains almost 90% of the atmosphere’s total mass • Almost all the Earth’s carbon dioxide, water vapor, clouds, air pollution, weather, and life forms are in the troposphere

  6. Stratosphere: • Air is thin, contains little moisture • Lower stratosphere= extremely cold • Temp rises as the altitude increases • Stratosphere=in ozone layer • Ozone layer= protects life on Earth by absorbing harmful ultraviolet radiation

  7. Mesosphere: • Middle layer above atmosphere • Coldest layer • Temperature decreases as altitude increases • Temp can reach -93 degrees celsius

  8. Thermosphere: • Uppermost layer • Temp increases as altitude increases (particles moving very fast)

  9. Ionosphere: Home of the Auroras • Electrically charged particles=therefor called the ionosphere • In polar regions these ions radiate energy as shimmering lights called auroras

  10. Section Two: Atmospheric Heating • Energy in the atmosphere • Earth receives energy from the sun by radiation • Energy transferred by waves • Conduction: energy transfer by contact 1. thermal conduction 2. thermal energy is transferred from warm to cold areas • Convection: energy transfer by circulation 1. cycle of warm air rising and cool air sinking causes movement of air-convection current

  11. II. Greenhouse Effect • 70% of the radiation that enters the Earth’s atmosphere is absorbed by clouds and Earth’s surface-this is converted into thermal energy (energy that warms the planet) -short wave visible light is absorbed and reradiated into the atmosphere as long-wave thermal energy B. Atmosphere is like a blanket that traps enough energy to make Earth livable

  12. Radiation Balance: for Earth to be livable-energy received from sun and amount of energy returned to space must be approximately equal-the balance of incoming energy and outgoing energy is called the radiation balance • Increasing levels of greenhouse gases could cause a global warming

  13. Section 3 (p. 14)Global Winds and Local Winds • Wind= the movement of air caused by differences in air pressure • Air rises at the equator and sinks at the poles: -the equator receives more direct solar energy -the air at the equator is warmer/less dense -warm air rises and creates a low pressure area -the warm air flows towards the poles -the poles are colder and more dense so the air sinks -this creates an area of high pressure

  14. Pressure belts are found every 30 degrees • Air travels in many large circular patterns called convection cells • Convection cells are separated by pressure belts • Pressure belts=bands of high pressure and low pressure found at every 30 degrees latitude

  15. The Coriolis effect • Winds do not travel directly north or south because the Earth is rotating • The apparent curving of winds and ocean currents due to the Earth’s rotation is called the Coriolis effect

  16. Global Winds • The combination of convection cells found at every 30 degrees latitude and the Coriolis effect produces patterns of air circulations called global winds • The major global wind systems are: • Polar easterlies • Westerlies • Trade winds

  17. Jet Streams: atmospheric conveyer belts • Jet streams are narrow belts of strong winds that blow in the upper troposphere

  18. Local Wind • Local winds move short distances and can blow from any direction • Shorelines or mountains can produce temperature differences that cause local winds • Mountain and valley breezes are other examples of local winds caused by an area’s geography