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CID#: ____________________
Physics 137
Unit Test #4
Wednesday-Thursday, December 12-13, 2007
Maximum score: 102 points. No time limit. Submit test copy and answer sheet
Instructor: Clark G. Christensen
(Fill in your CID# if you would like this copy returned to you.)
MULTIPLE CHOICE (2 points per question)
1. The flickering that is sometimes perceived in lightning is caused by (a) clouds of irregular opacity between
the observer and the lightning, (b) multiple strokes within a single lightning discharge, (c) bright, beadlike
features along the path of a stroke, (d) forked lightning wherein the light travel time to the observer is
different for different forks, (e) the differential light travel time from different points along the lightning
bolt to the observer.
2. When a strong downdraft associated with a thunderstorm (downburst) reaches the ground it fans out into a
strong horizontal surface wind, which, if it is confined to an area extending less than 4 kilometers across, is
known as a (a) gale, (b) katabatic wind, (c) mesocyclone, (d) microburst, (e) vortex.
3. The Milankovitch Theory proposes that climatic changes are due to (a) variations in the earth's orbital
motion as it travels through space, (b) volcanic eruptions, (c) solar variability, (d) changing levels of CO2 in
the earth's atmosphere, (e) particles suspended in the earth's upper atmosphere.
4. Which of the tornados in the figure at the right is most likely closest to
dissipating?
5. The interior of a car is quite safe during a lightning storm because (a) the
car's radio antenna acts as a lightning rod, (b) metal objects do not conduct
(a)
(b)
electricity, (c) the rubber tires prevent the car from being struck, (d) the
electrical current travels around the passengers through the metal car body,
(e) lightning cannot hit a moving target.
6. In the northern hemisphere a 1000-foot increase in altitude has about the
same effect climatically as traveling northward a distance of about how
(c)
(d)
many miles? (a) 20, (b) 50, (c) 200, (d) 600, (e) 1200, (f) 2400.
7. The lowest winter temperature ever observed in the northern hemisphere occurred (a) in Alaska, (b) on the
Arctic ice pack, near the north pole, (c) in Greenland, (d) in Siberia, (e) on the Norwegian Arctic island of
Spitzbergen.
8. Evidence suggests that an increase in the number of sunspots causes (a) no measurable effect on the sun's
luminous energy output, (b) a slight (~0.1%) increase in the sun's luminosity, (c) a slight (~0.1%) decrease
in the sun's luminosity, (d) a small but easily measurable (~1.0%) increase in the sun's luminosity, (d) a
small but easily measureable (~1.0%) decrease in the sun's luminosity.
9. When a change produces an effect which effect then causes a weakening of the original change, the causeeffect relationship is referred to by the term (a) "negative feedback," (b) "positive feedback," (c) "paradox,"
(d) "glaciation."
10. In the northern hemisphere which of the following is characteristic of both hurricanes and middle latitude
cyclones? (a) surface weather fronts, (b) generally eastward motion, (c) winds that increase in intensity
with height above the surface, (d) central subsidence, (e) counterclockwise circulation, (f) all of the
preceding.
11. In the western United States most mountain ranges (a) have nearly uniform precipitation amounts along all
elevation contours, (b) tend to have more precipitation on their eastern slopes than on their western slopes,
(c) tend to have more precipitation on their western slopes than on their eastern slopes, (d) have highly
inconsistent precipitation patterns.
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12. The circle in the figure at the right represents a wind streamline associated
with the funnel of a tornado. The four primary points of a compass, with respect
to the center of the funnel are also indicated. Assume that the tornado is
W
E
in the United States, circulating in the most common direction and also
moving in the most common direction for US tornado motions. If these
assumptions are correct, in which quadrant of the tornado are the surface
S
wind speeds the greatest? (a) northeast, (b) northwest, (c) southeast, (d) southwest,
(e) the surface wind speeds are the same in all four quadrants.
Physics 137
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Unit Test #4
13. The difference between hurricanes and typhoons is (a) type of energy source, (b) the greater intensity of
typhoons, (c) the greater size of typhoons, (d) the direction of wind circulation around the eye, (e) the
geographical region of occurrence.
14. Suppose it is warm and raining, but a cold front is moving toward your location. Directly behind the cold
front it is cold and snowing. Still further behind the front the weather is cold and clearing. If the front
continues to move with its present motion it will reach your area six hours from now. A persistence
forecast for your area for 12 hours from now would be: (a) cold and clearing, (b) cold and cloudy, (c) cold
and snowing, (d) warm and raining, (e) not enough information is given to infer what the persistence
forecast would be.
15. Thick sheets of ice advanced over North America as far south as New York as recently as: (a) 1816 ("the
year without a summer"), (b) 1550, (c) 18,000 to 22,000 years ago, (d) 2,000,000 years ago, at the
beginning of the Pleistocene epoch.
16. Just before a strengthening storm becomes a hurricane it is classified as a/an (a) tropical depression, (b)
easterly wave, (c) tropical storm, (d) cyclone, (e) tropical disturbance.
17. Hurricanes do not occur in a belt within 5° latitude of the equator because (a) the upper-level atmosphere
that near the equator is never cold enough to provide the requisite pool of upper-level cold air, (b) the
Coriolis force at such low latitudes is simply not adequately strong to force the required clockwise or
counterclockwise circulation, (c) the equatorial belt is too close to the intertropical convergence zone
(ITCZ) which inhibits organized storm formation, (d) the subtropical high along the equatorial belt is a
region of atmospheric stability where major storm formation cannot occur.
18. Most of the destruction caused by hurricanes is a consequences of (a) high winds, (b) flooding, (c)
tornadoes, (d) hail.
19. The middle-latitude cyclone and associated fronts in the figure
at the right are centered in the central United States. At which
of the indicated positions, (a-e), are tornados most likely to
form?
(a)
20. Which of the phenomena in the following list is not virtually
(b)
always associated with cumulonimbus clouds? (a) hail,
(d)
(e)
(b) hurricane, (c) inversion, (d) lightning, (e) tornado.
(c)
21. Which of the following areas in the United States
would be most likely to experience
thunderstorms, hurricanes and tornados, all during the course of one year? (a) Pacific Coast states, (b) New
England states, (c) Gulf Coast States, (d) Great Plains states, (e) Rocky Mountain states.
22. A forecast which is the "average" of several different methods and/or several different computer models is
known as a/an ________forecast. (a) analog, (b) climatological, (c) ensemble, (d) persistence, (e) steady
state, (f) weather type.
23. The Russian scientific station at Vostok, Antarctica, once recorded a temperature of -129°F, the coldest
temperature ever recorded on the earth’s surface. This is colder than the lowest temperature ever recorded
at the South Pole. Why? (a) Vostok is at a higher altitude than the South Pole. (b) Vostok is considerably
farther from the coast than the South Pole. (c) There is no permanent weather-recording facility at the
South Pole. (d) This is a consequence of a random variation. The South Pole is actually colder than Vostok
and eventually will record a temperature lower than this.
24. Aerosals do not tend to (a) increase the temperature of the atmospheric layer in which they reside by
absorbing radiation, (b) produce warmer surface nighttime temperatures by absorbing and reradiating
infrared radiation, (c) produce cooler surface daytime temperatures by reflecting sunlight, (d) enhance
precipitation by acting as condensation nuclei, (e) produce a net surface warming effect.
25. The Maunder Minimum refers to a time when (a) the earth is in the coldest period of an ice age, (b) the tilt
of the earth's axis is at its minimum value, (c) the earth's distance from the sun is at its minimum value, (d)
abnormally few snowstorms occur over the United States, (e) there are few or no sunspots on the sun.
26. A forecast of an extended period of dry weather would most likely be made for a region beneath (a) an
upper-level trough, (b) the polar front jet stream, (c) a cold pool of air aloft, (d) an upper-level ridge, (e) a
shortwave trough.
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Physics 137
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Unit Test #4
27. Normally, within a thunderstorm, the upper parts of the cloud are ______ charged and the lower parts are
______ charged. (a) negatively, positively; (b) negatively, negatively; (c) positively, negatively; (d)
positively, positively.
28. The highest daytime temperature ever recorded in the United States occurred in (a) Death Valley,
California, (b) Hawaii, (c) Southern Arizona, (d) Southern Florida, (e) Southern Texas.
For the next three questions, please refer to the chart below.
29. The image at the right is a
national 500-mb chart.
The local weather trend
for the time at which the
chart was prepared and
the next several hours
would most likely be one
of (a) clear skies, with air
stagnation and little
change in conditions, (b)
decreasing clouds and
storminess, (c) increasing
clouds and storminess, (d)
persistent fog.
30. Assume that following the
time of validity for the
chart the atmospheric
Rossby waves move in
their usual direction. If
so, then the temperature in
Provo, 48 hours after the
time for which the chart
is valid will probably be (a) about the same as at the time of the chart, (b) lower than at the time of the chart, (c)
higher than at the time of the chart, (d) there is no basis for making a temperature prediction.
31. The position of the western trough axis associated with the accompanying 500-mb chart is best characterized as
(a) just off the Pacific coast, (b) over California, (c) over Western Nevada, (d) over Utah, Idaho and Montana,
(e) over the Rockies.
32. Which of the following statements best describes the difference between a hazardous weather advisory which is
termed a "warning" and one which is termed a "watch?" (a) A "warning" is issued many hours in advance of
anticipated hazardous weather while a "watch" is issued when the hazardous weather is either imminent or
already occurring, (b) a "watch" is issued many hours in advance of anticipated hazardous weather while a
"warning" is issued when the hazardous weather is either imminent or already occurring, (c) a "warning" is
issued for weather conditions likely to produce a major hazard while a "watch" is issued when the anticipated
conditions are deemed only a minor hazard, (d) a "watch" is issued for weather conditions likely to produce a
major hazard while a "warning" is issued when the anticipated conditions are deemed only a minor hazard, (e)
"warnings" are issued for cold-weather hazards while "watches" are issued for warm-weather hazards, (f)
"watches" are issued for cold-weather hazards while "warnings" are issued for warm-weather hazards.
33. The earth's orbital tilt oscillates between limits somewhat less than and somewhat greater than its current
value of 23½°. At a time when the orbital tilt is near its minimum value, which of the following would
probably not be true? (a) There would be less seasonal temperature variation between summer and winter
than there is at present. (b) More snow would fall during the winter in polar regions than at present. (c)
There would be less likelihood of glaciers at high latitudes than at present. (d) There would be less seasonal
motion of the ITCZ than at present.
34. Fifteen seconds after seeing lightning you hear the associated thunder. The distance to the lightning, in
miles, is about (a) 1, (b) 3, (c) 5, (d) 15, (e) 45.
Physics 137
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Unit Test #4
35. At what location in the United States would a long-term observer personally experience the greatest number
of thunderstorms? (a) Central Florida, (b) the Central Plains, (c) the Central Rockies, (d) New England, (e)
Southern California.
36. Which of the following is not an atmospheric condition conducive to the formation of hurricanes? (a) a
region of converging surface winds, (b) warm water, (c) strong upper-level winds, (d) cold air aloft, (e)
warm, humid surface air.
37. Which of the following phenomena always occurs prior to a lightning discharge? (a) air ionization, (b)
fulgerite genesis, (c) rainfall, (d) solar heating of the surface.
38. The greatest source of a hurricane’s energy is (a) sensible heat transferred directly from the oceanic surface
to the atmosphere, (b) warm advection aloft, (c) warm surface advection, (d) the latent heat of condensation
released by condensation in the clouds.
39. Which would you not expect to observe as the eye of a hurricane is passing directly over your area? (a) an
increase in surface temperature, (b) a very low surface pressure reading, (c) high winds, (d) little or no
precipitation.
40. Severe thunderstorms are different from most air-mass thunderstorms in that severe thunderstorms (a)
contain thunder and lightning, (b) have an anvil, (c) contain hail, (d) have a strong updraft and downdraft,
(e) have a tilted or twisted updraft in the mature stage.
41. Throughout most of the earth's history the average global temperature is believed to have been (a) within 1°
or 2°C of what it is today, (b) several °C cooler than it is today, (c) several °C warmer than it is today, (d) at
least 20°C cooler than it is today, (e) at least 20°C warmer than it is today.
42. A forecast method that compares past weather maps and weather patterns to those of the present is (a)
persistence forecasting, (b) the analog method, (c) the trend method, (d) ensemble forecasting, (e)
climatological forecasting.
43. A certain North Atlantic hurricane is tracking directly towards the northwest. The highest surface winds
associated with the hurricane are probably in what direction from the storm's eye? (a) northeast, (b)
southeast, (c) southwest, (d) northwest, (e) there is no preferred direction; the surface winds are probably
about equally strong in all directions.
44. If trapped in a flat, open area during an active thunderstorm, the best way to protect oneself is to (a) lie flat
on one’s face, (b) lie flat on one’s back, (c) squat, (d) sit on the ground, (e) stand motionless, (f) run.
45. In a tropical wet-and-dry climate, the dry season occurs with the (a) high sun period (summer), (b) low sun
period (winter), (c) closest proximity of the ITCZ, (d) all of the above.
46. A particular computer code used to model the weather is known to give more accurate forecasts if
prognostications are calculated using one-minute time increments than if larger time increments are used.
However forecasts are generally prepared using fifteen-minute time increments. Why? (a) Other things
being equal, it takes fifteen times as much computer time to do the more accurate forecast. (b) Such
differences in accuracy are generally marginal, thus it is not worth the extra trouble to use the shorter
increment. (c) Most computer codes are written in such a way as to not allow any flexibility in the choice
of time increments. (d) Even though general accuracy improves with shorter time increments, the accuracy
at a particular site (that for which the forecast is prepared) may be greater with a longer time increment.
47. In the vicinities of a persistent high pressure systems, e.g., the Bermuda high or Pacific high, precipitation
amounts tend to be (a) greater in the centers of the systems than near their boundaries, (b) greater on the
eastern sides of the highs than on their western sides, (c) greater on the western sides of the highs than on
their eastern sides, (d) uniform in all directions from the highs' centers.
48. Which of the following conditions would most likely produce net warming at the earth's surface? (a) an
increase the amount of low-level global cloudiness, (b) an increase in the amount of sulfur-rich particles in
the stratosphere, (c) a decrease in the energy output of the sun, (d) an increase in the amount of global snow
cover, (e) an increase in the amount of high-level global cloud cover.
49. The unusual summer cold of the "year without a summer" (1816) was probably caused primarily by (a)
atmospheric soot from coal fires, (b) unusually high concentrations of volcanic particulates and gases in the
atmosphere, (c) an extremely large and persistent sunspot, (d) atmospheric dust caused by an extremely
large meteorite, (d) deforestation in emerging industrial countries, (e) earth's close encounter with a comet.
Physics 137
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Unit Test #4
50. Which of the following forecasts do you
think would not be issued, based on the
constant-height lines shown on the adjacent
500-mb chart? (a) warmer than average
temperatures over the western third of the
United States, (b) lower than normal
temperatures over the eastern half of the
United States, (c) higher than normal
precipitation over the southwestern section
of the United States, (d) unsettled weather
over the mid-Atlantic states.
51. (Bonus question, fill in the blanks.)
The approximate time at which I entered
the Testing Center was __________. At
that time the outdoor temperature was approximately _________ °F. (2 points if your estimate is
in error by 0°F to 4°F, 1 point if your error is 5° to 9°F, 0 points otherwise. The ESC temperature
at the time you entered the TC will be used to grade your answer.)
If you would like to have this copy of the exam returned to you, you must write your CID#
and/or name at the top of the first page!