1. Atmospheric Movement and Local Weather

2. 4. Atmosphere – the gasses held to Earth by gravity; the most dense are held near the surface.

3. 2. Air Pressure a measure of the weight of the atmosphere on a given area (barometric pressure). Measured with a barometer.

4. 5. Barometer – instrument used to measure air pressure

5. 26. Wind– a current of air moving from high pressure to low pressure areas

6. 3. Anemometer – instrument used to measure wind speed

7. 13. Humidity – amount of water vapor present (dissolved) in the air.

8. 20. Psychrometer – instrument used to measure humidity in the air

9. 21. Radiation– the emission of energy as electromagnetic waves

10. 7. Conduction– the process by which heat is directly transmitted through a substance

11. 8. Convection Currents – cyclical (circular) currents caused by density differences

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

13. 9. The Coriolis Effect – effect of Earth’s rotation on the path of air and water. Causes paths to curve.

14. Global Convection Cells

15. http://www. pbs. org/wgbh/nova/vanished/jetstr_five
14. Jet Stream – narrow bands of high speed wind high in the atmosphere. Moves west to east in Northern Hemisphere.

16. 19. Prevailing Winds - global wind currents at mid-latitudes; mostly blows in one direction

17. 1. Air Masses Bodies of air with about the same temperature
and humidity throughout

18. 18. Ocean Currents generated by wind, temperature and
a continuous, directed movement of seawater
generated by wind, temperature and
salinity differences

19. A strong surface current in the Atlantic Ocean that causes warmer climate along the East coast of the US and in NW Europe
11.Gulf Stream

20. http://esminfo. prenhall
ations/animations/26_NinoNina.html
10. El Nino – period when Pacific surface waters along South American are warmer than normal; impacts temperature and rainfall in U.S.

21. 16. La Nina – period when surface waters in Pacific are unusually cool; impacts temperatures and rainfall in the U.S.

22. Why does the Earth have wind and ocean currents?
Reflection Question

23. Variables Affecting Local Weather

24. When convection and winds cause air masses to move, they bump into one another.
The area where two air masses meet is called a front.
Most severe weather occurs near frontal boundaries.
25. Weather Fronts – area where two air masses with different temperatures and pressures meet.

25. 6. Cold Front - Cold air meets warm air - Fast moving and stormy, severe weather is likely

26. Cold Front Symbol

27. 24. Warm Front - Warm air meets cold air - Slow moving with less severe weather

28. Warm Front Symbol

29. Warm and cool air masses that are not strong enough to move one another
Sits still for a long period of time
23. Stationary Front

30. Stationary Front Symbol

31. 12. High Pressure— Cool air sinks, clockwise circulation, and has clear, sunny skies.

32. 17. Low Pressure— Warm air rises, counter clockwise circulation, and has cloud formation and possible bad weather

33. Frontal Boundary Simulations
ve_art/weather_fronts/
Frontal Boundary Simulations

34. High and Low Pressure Circulation

35. Air pressure is measured with a barometer in millibars.
Millibars are represented by connected lines of equal pressure. This is a lot like the topographic map lines.
The closer together the lines are, the faster the wind speed.
The farther apart the lines are, the slower the wind speed.
Air Pressure and Wind

36. The Earth’s Insulator The Sun heats the water and land every day.
Land heats up rapidly, but cools off rapidly.
Desert
Water heats up slowly, but cools off slowly.
Swimming at night
The heat retained by the oceans is what keeps our planet insulated.
The Earth’s Insulator

37. The heating and cooling of water and land produces land breezes and sea breezes.
High pressure moves toward low pressure, pushing the warm air upward.
As warm air rises, cooler air moves in and replaces it.
Land and Sea Breezes

38. 15. Land Breeze– happens at night when the water is warm (low pressure) while the land is cool (high pressure)

39. 22. Sea Breeze– happens during the day when the water is cool (high pressure) and the land is warm (low pressure)

40. Sea Breeze and Land Breeze Simulation
/terc/content/visualizations/es1903/es1903pag e01.cfm?chapter_no=visualization
Sea Breeze and Land Breeze Simulation

41. How do global patterns of atmospheric movement affect local weather?
Reflection Question