1. Chapter 5 study guide
1.   Describe the relationship between atmospheric pressure and elevation.
2.   Describe the relationship between temperature and atmospheric pressure.
3.   Describe an isobar.
4.   What is wind? Describe the function of the wind on the earth.
5.   What two factors influence wind direction? How do these factors function to influence wind direction?
6.   How are winds named? Define windward, leeward and prevailing winds.
7.   Describe the idealized model of Earth’s pressure and wind systems. (Figure 5.12)

2. Study Guide Chapter 5 8. Define gyres.
9.   Describe the effects of seasonal migration in California.
10. What is El Nino?
11. Describe local winds in our area. (land breeze- sea breeze, Santa Ana winds, mountain & valley breezes)
12.  Describe the upper air wind system.

3. Weight of the Atmosphere
The atmosphere exerts a pressure of 14.7lbs/sq in. (1034 grams/cm)
Atmospheric pressure is important because variation in pressure causes our atmospheric circulation 3

4. Pressure Units Meteorologists prefer to work in millibar (mb) units
Standard sea-level pressure of mb will cause mercury to rise to 76 cm or inches. See Fig. 5.1 text. 4

5. Variations in Air Pressure
Air pressure decreases with elevation
Humans not generally sensitive to small variations in air pressure 5

6. Mapping Pressure Distribution
Isobar = lines of equal pressure 6

7. The air moves down a pressure gradient
The air moves down a pressure gradient. Just like water rolling down a hill from high to low elevation.

8. Low Atmospheric Pressure8

9. High Atmospheric Pressure9

10. Which is High Pressure Which is Low?10

11. Cyclones and Anticyclones
Fig 5.3 11

12. Horizontal Variation in Air Pressure
Unequal distribution of insolation results in uneven heating of planet. Pressure and temperature. relationship?
Other factors include: differential heating of land and water, different albedos of surfaces
Equator low pressure why?relationship pressure and temperature
5.13 12

13. Wind Wind is the horizontal movement of air.
Winds are named from the direction they
are coming from. A North
wind is coming from the North.

14. Fig. 5-7, p. 121 14

15. Winds are transportation for
energy and moisture. Winds are an attempt to keep the Earth’s temperature in equilibrium.

16. Wind circulation patterns would be simple if pressure driven by temperature changes were the only influence on global wind circulation. 16

17. Fig. 5-13, p. 127 17

18. Fig. 5-15, p. 130 18

19. Global Wind Systems Subtropical High Pressure
Source of Trade Winds and Westerlies
Horse Latitudes
Trade Winds
N and S
Northeast and Southeast Trades
Pilots flying West
Hawaiian islands pleasant

20. Global Wind Systems ITC (Intertropical Convergence Zone)
Doldrums (50N-50S)
Winds converge
Weak winds
Idealized model
Changes due to land and ocean masses
Seasonal changes-pressure belts move North in summer.

21. Coriolis Effect Surface Friction
The second factor that influences our global wind circulation patterns is the Coriolis Effect. The Coriolis Effect is the apparent shift in the path of a fluid or object moving over Earth’s surface, caused by the rotation of the Earth. This force causes moving objects near the Earth’s surface to be turned westward from their original paths. 21

22. Effects of Seasonal Migration
Seasonal migration will most affect those regions near the boundary zone between two wind or pressure systems
California is an example of a region located within a zone of transition
5.16 22

23. Land and Sea Breeze
Fig. 5-9, p. 123 23

24. Mountain & Valley Breezes (local)
Mountain Breeze
Valley breeze
5.10 24

25. Local Winds 5.11 Chinook (USA rocky mtns)
Santa Ana- compressed warm and dry air.
Foehn wind- Alps
Santa Ana- High Pressure build up in desert- through mountain areas. Down- warm up, dry desert. Page 129
5.11 25

26. p. 125 26

27. Upper Air Winds
Include the upper air Westerlies and polar jet streams. About 16,500 ft.
miles in width
1-2 miles in depth
“Internal ribbon of air” See Fig. 5.19
Less complex than surface winds.
Fast moving- 100 mph west to east move weather.

28. Jet streams

29. Ocean currents
Like winds ocean currents distribute heat and energy of the Earth.
Surface currents that move in broad circulatory patterns are called gyres.
Ocean currents are affected by the Coriolis Effect, winds, salinity, and temperature.

30. Fig. 5.24

31. El Niño
El Niño is a warm, weak counter current that replaces the normally cold (upwelling) coastal waters
El Niño can last for many months and water temperatures are raised for thousands of miles
Exceptionally strong El Niños impact worldwide weather . 31

32. El Niño
Sir Gilbert Walker discovers a “seesaw” pattern of air pressure in the Pacific called the Southern Oscillation 32

34. Fig. 5-25, p. 140 34

35. Interactivity
Envrs-chp. 6 number 3.