Earth Science - The Basics Segment “Air Currents”

1. United Streaming Video Earth Science - The Basics Segment “Air Currents”

2. Weather Patterns • Changes in the weather patterns occur as the earth tries to equalizethe temperature. • Global Wind Currents • Global Ocean Currents

3. Checkpoint • Why is it trying to equalize the temperatures? • The Earth is heated unequally due to the tilted axis

4. Global Wind Patterns • The Earth is in a constant battle to equalize it’s temperature. • It never succeeds, because our planet is hotter in some places than in others.

5. Global Wind Patterns • Earth’s air is always on the move to move • Cool air sinks • Warm air rises • Forms convective currents

6. Global Wind Patterns • Winds carry heat north from Earth’s equator • Winds carry colder air south toward the equator.

8. Prevailing Wind Patterns

9. MoreDirect Sun Hot 0 o Equator 90 o S 60 o N 90 o N 30 o S 60 o S 30 o N

10. Prevailing Wind Patterns

11. Rainforests of the World Most rainforests are near the equatorbecause this is where the air is rising, creating clouds and rain.

12. Deserts of the World Most deserts are at 30o N and S Latitude because the air is sinking, dryingit out.

13. Prevailing Wind Patterns

14. Prevailing Global Wind Currents Name:____________________ Color code the following Where air is rising (Red) Where air is sinking (Blue) Where the worlds deserts are (Yellow) Where the worlds rainforests are (Green) Why does the air rise? Why does the air sink? What drives (causes) the global wind currents to move?

16. The Jet Stream • The jet stream is a river of fast moving airin high in the atmosphere that pushes fronts and controls other weather patterns.

17. North America Air Masses • An air mass is a largebody of air that has similartemperature and moisture properties.

18. Air Masses • Twoways to identify air masses by the amount of moisture • Continental(c) - Located over large land masses - DRY • Maritime(m) - Located over the oceans - HUMID

19. Air Masses • Twoways to identify air masses by the amount of temperature • Polar(P) - Cooler, • Tropical(T) - Warmer,

20. Air Masses • They are then put together to describe the air mass • cT – Dry warm • cP – Drycold • mT – Humid warm • mP – Humid cold

22. North America Air Masses

23. Type of Air Masses Mp Cp 30o Latitude Tropic of Cancer Ct Mt 0o Latitude Equator 30o Latitude Tropic of Capricorn Ct Mp

25. Fronts • A front is a boundary between air masses that have different characteristics. • There are different types of fronts • Cold • Warm • Stationary

26. Cold Front • The cold dense air behind a cold front pushes the warmer air up forming cumulus clouds. • A cold front usually movesfastandcausesshowersand thunderstorms.

27. Warm Front • The warm air behind a warm fronts pushes over the cooler air ahead of it forming stratus clouds. • A warm front causessteadyrain, drizzle and fog.

28. Stationary Front • A stationary front occurs when a front stopsmoving. • The air is unsteady and sometimes causes rain, and sometimes causes showers.

29. Pressure Systems • High Pressure: winds go clockwise • good weather • Few clouds, • no rain • Low Pressure: winds go counter-clockwise • usually means bad weather • Lots of clouds, • rain is more common

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