Weather and Atmosphere

1. Weather and Atmosphere

2. Layers of the Atmosphere

3. Sample Question How does the temperature of the stratosphere compare to the mesosphere? • It is colder than the mesosphere because the stratosphere contains the ozone layer • It is warmer than the mesosphere because the stratosphere contains the ozone layer • It is colder than the mesosphere because the stratosphere contains the ionosphere • It is warmer than the mesosphere because the stratosphere contains the ionosphere

4. Air Pressure and Density • Air pressure: Air pressure decreases as you go up in the atmosphere because there are fewer air molecules as altitude increases • Density: Density decreases in our atmosphere as we go up. Most of the mass of the atmosphere is near the surface.

5. Sample Question Why does air pressure decrease from the troposphere to the exosphere? • Because there are fewer air molecules as altitude increases • Because there are more air molecules as altitude increases • Because there are higher temperatures as altitude increases • Because there are lower temperatures as altitude increases

6. Components of Air 78% = Nitrogen 21% = Oxygen 1% =CO2, Argon and other gases

7. Heat Transfer in the Atmosphere

8. Sample Question How does convection of air produce thunderstorms? • By causing warm air to sink and cold air to rise • By causing warm air to rise and cold air to sink • By causing both warm air and cold air to rise • By causing both warm air and cold air to sink

9. Global Wind Belts

10. Global Winds • Doldrums: Low pressure near the equator; warm air rises to the top of the troposphere; heavy evaporation from warm ocean water fuels tropical storms • Tradewinds: Blow from the east; move from the horse latitudes toward the poles; strong and steady but die as they reach the equator • Horse Latitudes: High pressure zones 30N and 30S of the equator, warm air traveling from the equator cools and sinks here; weather tends to be clear and dry

11. Global Winds • Westerlies: Blow from the west; move from the horse latitude towards the poles; bring storms across much of the United States • Polar Easterlies: Blow from the east; move from the polar regions to the mid latitudes; stormy weather often occurs when cold air of the easterlies meets warm air of the westerlies

12. Coriolis Effect • If Earth did not rotate, global winds would flow directly from the poles to the equator • The Earth’s rotation changes the direction of winds • In the Northern Hemisphere, winds curve to the right and in the Southern Hemisphere, winds curve to the left

13. Coriolis Effect

14. Sample Question Which best explains how the Coriolis effect influences weather conditions? • It causes winds to rotate, forming tornadoes on Earth • It causes winds to move to the right in the southern hemisphere • It causes winds to turn to the right in the northern hemisphere • It causes winds to follow a straight-line path around Earth

15. Pressure Systems • High Pressure: Air sinks slowly; air moves all the way around a high-pressure center; large and change slowly; brings clear skies and calm air or gentle breezes • Low Pressure: Surrounds a center of low pressure; air moves upward and inward toward the lowest pressure and then up to high altitudes; can bring stormy weather

16. Sample Question • Which occurs within a high-pressure system? • A. The formation of clouds • B. The formation of hurricanes • C. Large clouds, as air rises • D. Calm weather, as sir sinks

17. Fronts • Cold Fronts: Forms when a cold air mass pushes a warm air mass and forces the warm air to rise; produce cumulonimbus clouds and precipitation are produced; brief, heavy storms are likely; after the storms, the air is cooler and often very clear • Warm Fronts: Forms when a warm air mass pushes a cold air mass and warm air rises slowly over the cold air; produces cloud covered skies; brings hours of steady rain; after front passes, the air is warmer

18. Fronts

19. Sample Question What has most likely occurred in this area? • A. A warm front has passed • B. A cold front has passed • C. A blizzard has taken place • D. A high-pressure system has stalled

20. Humidity and Dew Point Humidity Dew Point • Amount of water vapor in the air • Higher humidity makes the air seem hotter and damper • Temperature at which air with a given amount of water vapor will reach saturation • The higher the dew point of air, the more water vapor the air contains

21. Sample Question Four-Day Temperature Recordings at 3:00 PM On which day could the air have held the greatest amount of water vapor at 3:00 A. Thursday B. Friday C. Saturday D. Sunday

22. Sample Question Why is it important for the United States to monitor air pollution levels in other countries? • Air pollution can improve the ozone layer amounts in the atmosphere • Air pollution can travel to the United States and affect people’s health • The United States is the only country able to monitor the air quality • The united States has clean air and is able to help other countries

23. The Water Cycle http://www.enchantedlearning.com/wgifs/Watercycle.GIF Click link for water cycle diagram

24. Sample Question • Runoff is an important part of the water cycle. 1. What is the final destination for runoff that flows on the surface of the continents? 2. How can runoff water contribute to the weather in an area?

25. Answer