CHAPTER 9

 

ATMOSPHERE’S PLANETARY CIRCULATION

__________________________________________________________

 

MULTIPLE CHOICE QUESTIONS

 

1. Viewed from above in the Northern Hemisphere, surface winds about a subtropical high blow

a. clockwise and inward.

b. counterclockwise.

c. counterclockwise and outward.

d. clockwise and outward.

e. None of these is correct.

 

2. Viewed from above in the Southern Hemisphere, surface winds about a subtropi­cal high blow

a. clockwise and inward.

b. counterclockwise.

c. counterclockwise and outward.

d. clockwise and outward.

e. None of these is correct.

 

3. The eastern flank of a subtropical anticyclone is character­ized by

a. unstable air.

b. ascending air.

c. dry climates.

d. All of these are correct.

e. None of these is correct.

 

4. The western flank of a subtropical anticyclone is character­ized by

a. relatively stable air.

b. mostly descending air.

c. moist climates.

d. All of these are correct.

e. None of these is correct.

 

5. A broad region of light winds or calm air pre­vails

a. in subpolar lows.

b. in the trade wind belts.

c. along the horse latitudes.

d. near 60 degrees latitude.

e. along the Tropic of Cancer.

 

6. Subtropical anticyclones are ______-core circulation systems.

a. cold

b. warm

 

7. Over a broad region about the center of a subtropical high, the horizontal air pressure gradient is relatively ______ and winds are ______.

a. weak...............light or calm

b. steep...............light or calm

c. weak...............strong

d. steep...............strong

e. None of these is correct.

 

8. The trade winds blow out of the ______ flank of the subtrop­ical anticyclones.

a. poleward

b. equatorward

c. eastern

d. western

 

9. In the Northern Hemisphere, trade winds blow from the __________.

a. north

b. east

c. southeast

d. south

e. northeast

 

10. In the Southern Hemisphere, trade winds blow from the _________.

a. north

b. east

c. southeast

d. south

e. northeast

 

11. The global westerlies blow out of the ______ flank of the subtropical anticyclones.

a. poleward

b. equatorward

c. eastern

d. western

 

12. The tropical deserts of the world are found at latitudes near 30 degrees latitude because

a. the intertropical convergence zone occurs there.

b. of the doldrums.

c. of the sinking air associated with the polar front.

d. of the sinking air associated with the subtropical highs.

 

13. Viewed from above in the Northern Hemisphere, winds above the atmospheric boundary layer blow ______ about the center of a subtropical high.

a. clockwise and parallel to isobars

b. clockwise and across isobars toward low pressure

c. counterclockwise and parallel to isobars

d. counterclockwise and across isobars toward high pressure

e. None of the above is correct.

 

14. Viewed from above, surface winds blow ______ about the Icelandic low.

a. clockwise and outward

b. clockwise and inward

c. counterclockwise and outward

d. counterclockwise and inward

 

15. The trade winds of the two hemispheres converge in the

a. subpolar lows.

b. ITCZ.

c. polar highs.

d. subtropical highs.

e. None of these is correct.

 

16. The trade winds of the two hemispheres

a. diverge at the equator.

b. are highly variable in speed and direction.

c. flow toward the east in a pattern of long-waves.

d. are very persistent in direction.

e. None of the above is correct.

 

17. The intertropical convergence zone (ITCZ)

a. is a discontinuous belt of cumulonimbus clouds.

b. marks the convergence of the trade winds of the two hemispheres.

c. is located near the equator on average.

d. is a discontinuous belt of thunderstorms.

e. All of the above are correct.

 

18. A front is a narrow zone of transition between air masses that contrast in

a. temperature.

b. humidity.

c. density.

d. Any of these is correct.

e. None of these is correct.

 

19. Hadley cells are located in ______ latitudes of both hemi­spheres.

a. tropical

b. middle

c. high

 

20. Hadley cells are

a. located in middle latitudes.

b. similar to huge convection cells.

c. linked to the subpolar lows.

d. driven by the westerlies.

e. None of these is correct.

 

21. The intertropical convergence zone (ITCZ) is

a. also known as the horse latitudes.

b. an area of clear skies where the trade winds meet the middle latitude westerlies.

c. the sinking portion of the Hadley cells.

d. the persistent band of cloudiness near the equator.

 

22. In the Northern Hemisphere, with the shift from winter to summer, the semi-permanent subtropical highs shift __________.

a. eastward

b. northward

c. southward

d. westward

 

23. In the Northern Hemisphere, with the shift from summer to winter, the semi-permanent subtropical anticyclones shift __________.

a. eastward

b. northward

c. southward

d. westward

 

24. In the Northern Hemisphere autumn, the ITCZ shifts

a. eastward.

b. poleward.

c. westward.

d. equatorward.

 

25. In the Southern Hemisphere spring, the subtropical highs shift

a. eastward.

b. poleward.

c. westward.

d. equatorward.

 

26. The middle latitude westerlies are more energetic in ______ than in ______.

a. winter...............summer

b. summer...............winter

 

27. Long-waves in the westerlies undergo changes in

a. wavelength.

b. number of waves.

c. wave amplitude.

d. All of these are correct.

 

28. On a typical day, ______ Rossby long-waves encir­cle the globe.

a. 1 to 2

b. 2 to 5

c. 3.5

d. dozens of

e. more than 100

 

29. Which one of the following westerly wave patterns favors the maximum north-south exchange of air masses?

a. zonal flow

b. meridional flow

c. split flow

 

30. The westerly wave pattern that is likely to persist for the longest time is

a. zonal

b. meridional

 

31. A blocking pressure system is associated with a ______ flow pattern in the westerlies.

a. zonal

b. meridional

 

32. Across the United States, temperature contrasts are general­ly greatest during a ______ circulation pattern in the westerlies.

a. strong zonal

b. strong meridional

c. weak meridional

d. weak zonal

 

33. During droughts, when soil moisture is low, the Bowen ratio is relatively

a. low

b. high

 

34. In the Midwest, drought is most likely with a ______ circu­lation pattern in the westerlies.

a. strong zonal

b. split-flow

c. weak meridional

d. blocking

 

35. Horizontal divergence occurs to the ______ of an upper-air trough.

a. east

b. north

c. west

d. south

 

36. Horizontal convergence occurs to the ______ of an upper-air ridge.

a. east

b. north

c. west

d. south

 

37. Horizontal divergence occurs to the ______ of an upper-air ridge.

a. east

b. north

c. west

d. south

 

38. Horizontal convergence occurs to the ______ of an upper-air trough.

a. east

b. north

c. west

d. south

 

39. A synoptic-scale cyclone is most likely to develop on the ______ side of an upper-air trough.

a. east

b. north

c. west

d. south

 

40. A synoptic-scale cyclone is most likely to develop on the ______ side of an upper-air ridge.

a. east

b. north

c. west

d. south

 

41. In an essentially straight jet streak viewed from above, the strongest horizontal divergence takes place in the ______ quadrant.

a. left rear

b. right rear

c. left front

d. right front

 

42. The average winter location of the polar front jet stream is

a. southern Canada.

b. Iceland.

c. southern United States.

d. northern Canada.

e. Mexico.

 

43. The average summer location of the polar front jet stream is

a. southern Canada.

b. Iceland.

c. southern United States.

d. northern Canada.

e. Mexico.

 

44. The southern oscillation

a. was discovered by Sir Gilbert Walker early in the 20th century.

b. is a seasaw variation in air pressure across the tropical Indian and Pacific Oceans.

c. is linked to the development of El Niño.

d. All of these are correct.

e. None of these is correct.

 

45. In the Northern Hemisphere, Ekman transport of surface ocean waters is about _________ the surface wind direction.

a. 45 degrees to the left of .

b. 90 degrees to the left of

c. 90 degrees to the right of

d. 30 degrees to the right of

 

46. Upwelling

a. brings cold bottom water to the ocean surface.

b. is the long-term average condition off the northwest coast of South America.

c. is suppressed during El Niño.

d. supports important fisheries.

e. All of the above are correct.

 

47. Along the California coast, upwelling occurs when winds blow from the

a. north.

b. south.

c. east.

d. west.

 

48. An extreme and persistent El Niño

a. can be expected every year in mid-December.

b. may be accompanied by weather extremes in various parts of the world.

c. involves an interaction between the tropical Atlantic ocean and atmosphere.

d. seldom lasts longer than a few weeks.

 

49. During “neutral” conditions, sea surface temperatures are highest in the ________ tropical Pacific.

a. western

b. central

c. eastern

 

50. La Niña __________ follows El Niño.

a. sometimes

b. always