CHAPTER 7 CLOUDS, PRECIPITATION, AND WEATHER RADAR MULTIPLE CHOICE QUESTIONS 1. The activation temperature of most ice-forming nuclei is 0 C. a. above b. about c. well below 2. Hygroscopic nuclei water molecules. a. repel b. attract c. vaporize 3. Hygroscopic nuclei a. have numerous natural and human-related sources. b. are relatively abundant downwind of urban-industrial areas. c. favor cloud formation at relative humidities under 100%. d. All of the above are correct. e. None of the above is correct. 4. The relative humidity within a cloud is 100 percent. a. much less than b. about c. much greater than 5. Source(s) of condensation nuclei: a. forest fires b. wind erosion of soil c. seawater spray d. industry and agriculture e. All of these are correct. 6. The British naturalist who is credited with being among the first to devise a classification of cloud types is a. Benjamin Franklin. b. Stefan-Boltzmann. c. Luke Howard. d. Sir Isaac Newton. e. Charles Boyle. 7. Of the following cloud types, which one is coldest?
a. cirrus b. stratus c. cumulus d. altocumulus e. fog 8. Of the following cloud types, which one is warmest? a. cirrus b. cirrostratus c. cirrocumulus d. altostratus 9. Extreme nocturnal radiational cooling occurs when a. the pressure drops. b. temperatures are below freezing. c. winds are strong. d. skies are clear. 10. A cloud that forms when warm air overrides cold air is a. cumulus. b. cumulonimbus. c. cirrostratus. d. cumulus congestus. e. None of these is correct. 11. All of the following clouds typically have relatively low bases with the exception of a. cirrus. b. stratus. c. stratocumulus. d. fog. e. nimbostratus. 12. Cirrus clouds are typically composed of a. water droplets only. b. a combination of ice crystals and water droplets. c. ice crystals only. 13. Usually, only drizzle falls from a. cirrus clouds. b. stratus clouds. c. cumulus clouds. 14. Clouds at temperatures between 0 C and -9 C are typically composed of a. ice crystals only. b. a mixture of supercooled water droplets and ice crystals.
c. mostly supercooled water droplets. d. None of the above is correct. 15. A cloud develops as a consequence of local convection. a. cumulus b. stratus c. cirrus d. cirrostratus e. nimbostratus 16. The convective condensation level (CCL) closely corresponds in altitude to the base of a cloud. a. cirrostratus b. cumuliform c. altocumulus d. altostratus e. cirrus 17. Which one of the following cloud types would most likely be responsible for producing heavy rain? a. cumulus b. cumulonimbus c. altocumulus d. cirrocumulus e. cirrus 18. A cloud that exhibits considerable vertical development is a. fair-weather cumulus. b. altostratus. c. stratocumulus. d. cirrus. e. cumulonimbus. 19. A cloud that may be cold at the top and warm at low levels: a. cirrus b. cirrocumulus c. cumulonimbus d. cirrostratus 20. Cumulonimbus (thunderstorm) clouds typically are a. cold clouds. b. warm clouds. c. cold at high altitudes and warm at cloud base. d. None of the above is correct.
21. Disk shaped, mountain-wave clouds are known as a. altocumulus lenticularis. b. stratus. c. cumulonimbus. d. nacreous. 22. Mountain waves a. are stationary. b. are usually associated with prominent mountain ranges. c. may produce altocumulus lenticularis clouds. d. are standing waves. e. All of the above are correct. 23. A rarely seen cloud that forms in the upper mesosphere and may be composed of ice deposited on meteoric dust: a. noctilucent b. nacreous c. altocumulus lenticularis d. cirrus e. aurora borealis 24. All of the following clouds may be formed by waves propagating horizontally within the atmosphere with the exception of. a. altocumulus lenticularis b. altocumulus c. stratocumulus d. cirrocumulus 25. To be considered fog, visibility must be restricted to or less. Otherwise, the suspension is called mist. a. 5000 m b. 1000 m 26. In dense fog, the mixing ratio is the saturation mixing ratio. a. much less than b. about equal to c. greater than 27. Persistent radiation fog is likely to develop on a a. hilltop. b. river valley bottom. c. valley slope. d. mountain summit. e. None of these is correct.
28. Advection fog forms when a. warm humid air streams over the cold surface of a lake. b. extremely cold and dry air flows over a large unfrozen body of water. c. ascending humid air undergoes expansional cooling. 29. Fog formed when cold dry air streams over the surface of a relatively warm body of water is known as a. radiation fog. b. upslope fog. c. mist. d. steam fog. 30. At the same pressure, cold air is warm air and. a. less dense than...tends to rise b. more dense than...flows downslope 31. The type of fog formed in spring when mild humid air flows over an old snow cover is a. radiation fog. b. steam fog. c. arctic sea smoke. d. advection fog. e. upslope fog. 32. At saturation and at the same temperature, the vapor pressure is greater over than over. a. ice...water b. water...ice 33. Which one of the following has the greatest terminal velocity? a. ice crystal b. drizzle drop c. large hailstone d. raindrop e. snowflake 34. For a given particle, the terminal velocity is in air than in water. a. greater b. less 35. Most precipitation that falls in middle latitudes originates in clouds. a. cirrus b. cumulus c. nimbostratus or cumulonimbus d. altostratus
36. Most precipitation that falls in middle latitudes originates in clouds. a. warm b. cold 37. It takes the water content of about cloud droplets to form a single raindrop. a. 10 b. 100 c. 1000 d. 100,000 e. 1,000,000 38. A warm cloud is composed of a. tiny water droplets exclusively. b. ice crystals exclusively. c. a mixture of ice crystals and supercooled water droplets. d. supercooled water droplets. e. None of the above is correct. 39. When water or ice particles vaporize before reaching the group, appearing as dark curtains or streaks, this is known as. a. drizzle b. sleet c. virga 40. A cold cloud is composed of a. ice crystals. b. supercooled water droplets. c. a mixture of ice crystals and supercooled water droplets. d. Any of the above is correct. e. None of the above is correct. 41. The Bergeron-Findeisen precipitation process takes place within clouds. a. cold b. warm c. cirrus d. cirrostratus 42. In cold clouds, a vapor pressure that is for water droplets is for ice crystals. a. saturated...saturated b. saturated...unsaturated c. saturated...supersaturated d. supersaturated...saturated 43. The type of frozen precipitation sometimes produced by a summer thunderstorm is a. snow. b. freezing rain.
c. snow pellets. d. hail. e. sleet. 44. Rain that has a ph 5.6 is considered to be acid rain. a. higher than b. lower than c. equal to 45. Weather radar continually emits pulses of. a. sound waves. b. X-rays. c. gamma rays. d. microwaves. e. visible light. 46. Weather radar gathers information about precipitation in clouds by measuring the a. energy emitted by the precipitation particles. b. absorption characteristics of falling precipitation. c. amount of energy scattered back to the transmitter. d. amount of sunlight reflected off the falling precipitation. 47. Operating in the Doppler mode, weather radar detects particles moving the radar beam. a. perpendicular to b. directly toward or away from 48. Weather radar displays show the a. intensity of the return at the proper direction and distance. b. intensity of the return at the proper height and distance. c. the character of the returning signal, whether precipitation or ground clutter. d. All of the above are correct. 49. uses multiple beams sent out simultaneously, providing a faster, more detailed picture of the atmosphere. a. Phased array weather radar b. Doppler radar 50. Which type of rain gauge performs better at subfreezing air temperatures? a. tipping-bucket rain gauge b. weighing-bucket rain gauge