Download Spring 2007

ATMO 336
Exam 2 – Spring 2007
Name__________________________
Multiple Choice Section (2 points each)
1. The steam that you sometimes see above a pot of boiling water is nothing more than a high
concentration of water vapor.
(a) True
(b) False
2. Cloud-to-ground lightning is more common than in-cloud and cloud-to-cloud lightning.
(a) True
(b) False
Fill in the table below by lifting a parcel of air from the surface up to 4000 m above the surface,
then answer questions 3-7.
Elevation
4000 m
3000 m
2000 m
1000 m
0m
Environmental
Temperature
-8 C
-1 C
7 C
14 C
22 C
3. What is the parcel temperature at 4000 m?
(a) -18 C
(b) -10 C
(c) -6 C
Parcel
Temperature
Parcel Dew Point
Temperature
22 C
2 C
(d) -2 C
4. Where, if at all, will a cloud begin to form in the parcel?
(a) As the parcel moves above 1000 m (c) As the parcel moves above 3000 m
(b) As the parcel moves above 2000 m (d) A cloud does not form in the parcel
5. Where, if at all, does the parcel become unstable?
(a) When the parcel reaches 2000 m
(c) When the parcel reaches 4000 m
(b) When the parcel reaches 3000 m
(d) The parcel remains stable up to 4000 m
6. Which two changes to the environmental temperature will tend to make the parcel less
stable or more unstable as it is lifted upward?
(a) Cool the air at 0 m and cool the air above 3000 m
(b) Cool the air at 0 m and warm the air above 3000 m
(c) Warm the air at 0 m and warm the air above 3000 m
(d) Warm the air at 0 m and cool the air above 3000 m
7. Increasing the amount of water vapor in the air at the surface (0 m) will __________ .
(a) tend to make the parcel less stable or more unstable as it is lifted
(b) tend to make the parcel more stable or less unstable as it is lifted
(c) not affect the stability of the parcel as it is lifted
8. Why do rising parcels of air cool?
(a) Because they expand as the air pressure around them decreases
(b) Because water vapor evaporates, cooling the air in the parcel
(c) Because water vapor condenses, cooling the air in the parcel
9. The underlying reason that Bergeron process of precipitation formation works is that when
the temperature is below freezing, _________.
(a) the saturation mixing ratio over supercooled liquid water is lower than that over ice,
i.e., water will move from the ice crystals to the supercooled droplets.
(b) the saturation mixing ratio over supercooled liquid water is higher than that over ice,
i.e., water will move from the supercooled droplets to the ice crystals.
10. Precipitation falling from clouds that completely evaporates before hitting the ground is
called _________ .
(a) a rain shadow
(c) cloud fall
(b) a cloud curtain
(d) virga
11. Suppose a parcel of air is first forced to rise up over a mountain, then forced to sink back
down the other side. Assume that a cloud forms in the parcel as it rises upward and that half
of the condensed water falls out of the parcel as snow on top of the mountain. Compare the
temperature and relative humidity of the air in the parcel before it was lifted over the
mountain to the temperature and relative humidity after it comes back down the other side.
(a) Temperature and relative humidity are both lower after going over mountain.
(b) Temperature is lower and relative humidity is higher after going over mountain.
(c) Temperature is higher and relative humidity is lower after going over mountain.
(d) Temperature and relative humidity are both higher after going over the mountain.
12. At what time of day are severe thunderstorms and tornadoes most likely to occur?
(a) At night (b) Morning (c) Afternoon (d) All times are equally likely
13. Single-cell thunderstorms only last about one hour and begin to dissipate when
(a) lightning neutralizes all the electrical charge in the cloud
(b) all the precipitation particles in the cloud turn to ice
(c) downdrafts spread throughout the cloud and cut off updrafts
(d) solar heating at the ground begins to decrease
14. On average, which area of the United States experiences the greatest number of
thunderstorms per year?
(a) West coast (California, Oregon, Washington)
(b) Desert southwest (Arizona, New Mexico, southern Colorado, southern Utah)
(c) Gulf coast (Florida, Alabama, Mississippi, Louisiana)
(d) Southern great plains (northeast Texas, Oklahoma, Kansas)
15. A microburst is
(a) the beginning stage of a tornado
(b) a small, localized area of frequent cloud to ground lightning
(c) a burst of extremely heavy rain
(d) a small, but very strong downdraft
16. Strong vertical wind shear is a necessary ingredient in the formation of _________ .
(a) severe thunderstorms and tornadoes
(c) both (a) and (b)
(b) hurricanes
(d) neither (a) nor (b)
One day last summer, thunderstorms developed in both Tucson, AZ and Orlando, FL. Minutes
before the thunderstorms developed, the following conditions were measured at ground level:
Air temperature
Dew point temperature
Relative Humidity
Tucson, AZ
100 F
45 F
15%
Orlando, FL
85 F
70 F
60%
17. Which location will likely have the lowest cloud base (from ground to cloud bottom)?
(a) Tucson
(b) Orlando
18. Which location would most likely experience the strongest downdrafts and gust front winds?
(a) Tucson
(b) Orlando
19. If you see a lightning stroke and then 2 seconds later hear the thunder, how far away is the
lightning?
(a) Less than 0.5 mile (b) About 2 miles
(c) About 2.5 miles (d) About 10 miles
20. Thunder is caused by ________
(a) the rapid heating of air surrounding a lightning channel
(b) the explosion that occurs when + and – charges collide and neutralize
(c) strong, turbulent wind motions that occur inside the thunderstorm
(d) the collision between two thunderstorm clouds
21. The inside of a car provides relatively safe shelter from ____________ .
(a) tornadoes
(c) both tornadoes and lightning
(b) lightning
(d) neither tornadoes nor lightning
22. Most tornadoes produce wind speeds of 150 mph or higher.
(a) True
(b) False
23. More tornadoes occur over the United States than anywhere else on Earth.
(a) True
(b) False
24. Strong vertical wind shear is a necessary ingredient in the formation of _________ .
(a) severe thunderstorms and tornadoes
(c) both (a) and (b)
(b) hurricanes
(d) neither (a) nor (b)
25. What is the function of the mid-tropospheric “convective cap” or “inversion layer” in the
development of some supercell thunderstorms that may form tornadoes?
(a) It is a stable layer that holds back thunderstorm development at first, allowing energy
to build up in the lower troposphere, so that when the storm does fire, it is more
powerful.
(b) It is an extremely unstable layer, which promotes the rapid formation of very strong
updrafts, producing powerful thunderstorms.
26. Suppose you are tracking hurricane Rudy. On Monday morning the sea level pressure in the
center of the Rudy was 935 mb. On Tuesday morning the sea level pressure in the center of
Rudy went down to 909 mb. This indicates that hurricane Rudy is ________ .
(a) strengthening
(b) weakening
Fill in the blanks to complete the statement below
For a hurricane to strengthen, the ____#27____ must be stronger than the ____#28____.
(You may want to look at the diagram for short answer question #4b for help with this question).
27. Answer choices
(a) divergence (outflow) of air in the upper troposphere
(b) divergence (outflow) of air in the lower troposphere
(c) convergence (inflow) of air in the lower troposphere
(d) convergence (inflow) of air in the upper troposphere
28. Answer choices
(a) divergence (outflow) of air in the upper troposphere
(b) divergence (outflow) of air in the lower troposphere
(c) convergence (inflow) of air in the lower troposphere
(d) convergence (inflow) of air in the upper troposphere
29. With hurricane Katrina, the strongest winds and greatest storm surge affected which areas?
(a) New Orleans, LA
(c) Galveston, TX
(b) Miami, FL
(d) Biloxi, MS
30. In the United States, the average number of deaths per year caused by these two types of
extreme weather has been increasing recently. (Must apply to both answers)
(a) Tornadoes and Lightning
(c) Flash flooding and Lightning
(b) Tornadoes and Hurricanes
(d) Flash flooding and Extreme Heat
31. In the United States, a killer heat wave (with many deaths) is more likely to happen in ____ .
(a) a northern city like Philadelphia or New York
(b) a southern city like Houston or Atlanta
(c) a desert city like Phoenix or Las Vegas
32. According to the NY times article “Most Deadly of Natural Disasters: The Heat Wave”, a
vast majority of the people who suffered through and survived the 1995 Chicago heat wave
now realize just how deadly heat waves can be.
(a) True
(b) False
33. According to the NY times article “Most Deadly of Natural Disasters: The Heat Wave”, even
after the deadly heat wave of 1995, the city of Chicago has done nothing to help protect its
residents from future heat waves.
(a) True
(b) False
34. Which statement is most correct?
(a) We know CFCs destroy ozone in the stratosphere, so developed countries of the
world have for the most part stopped producing these chemicals.
(b) We know CFCs destroy ozone in the stratosphere, but most developed countries of
the world continue to produce it anyway.
(c) It is not known for sure whether or not CFCs destroy ozone in the stratosphere, but to
be safe most developed countries have stopped producing these chemicals.
(d) It is not known for sure whether or not CFCs destroy ozone in the stratosphere,
therefore developed countries continue to produce it.
35. The following weather conditions are forecast on a summer day in Tucson:
At 9 AM, sunny, air temperature = 87 F
At 11 AM, sunny, air temperature = 99 F
At 3 PM, sunny, air temperature = 108 F
Exposure to ultraviolet radiation will be greatest at what time of day?
(a) 9 AM
(b) 11 AM
(c) 3 PM
(d) All times are equal
Short Answer Section
Instructions: Everyone must answer questions 1 and 2, which are worth 6 and 8 points
respectively. For questions 3 and 4, select either (a) or (b), which are worth 10 points each.
Questions 3 and 4 are longer questions, so make sure you answer each part. Write your answers
on the short answer sheets provided. If you need more space use the back of the multiple choice
answer sheet.
1. What is a cloud? Describe how most clouds form. If it helps, you may use the concept of an
air parcel to describe how clouds form.
2. The incidence (number of reported cases) of skin cancer in the United States has been
increasing at a rate of about 2% per year since 1981. After hearing this news a friend of
yours says “the increase in skin cancer in the US is the result of the ozone hole caused by
CFCs.” Comment on the validity of your friend’s statement. Skin cancer rates in
southern Arizona are among the highest in the US. Give three reasons why residents of
southern Arizona are exposed to higher levels of ultraviolet radiation compared with
most of the rest of the US. Provide a brief explanation for each reason you give.
3. Select either (a) or (b)
(a) Explain what it means for the atmosphere to be unstable. Why must the atmosphere
be unstable for thunderstorm updrafts to form? What is the main source of energy for
the development of thunderstorm updrafts? Once rain begins to fall from a
cumulonimbus cloud, explain how thunderstorm downdrafts develop.
(b) What is a dome cloud in a thunderstorm (describing what it looks like is good
enough)? How is the dome cloud formed? What does it indicate about the
thunderstorm and the atmospheric conditions present at the time the thunderstorm
developed? Explain how hail forms. Comment on the possibility that a thunderstorm
with a dome cloud will produce large hail.
4. Select either (a) or (b); (b) is on the back of this page.
(a) A guest speaker on campus makes the following argument:
In 2004, three major Atlantic hurricanes hit the continental United States. In 2005, this
trend continued as four major hurricanes struck the continental United States. This is the
first time since 1850 that seven major hurricanes have made landfall over the continental
United States in two consecutive hurricane seasons. The timing of these storms coincides
with the warmest global average sea surface temperatures since 1850. [You can consider
all of the above as true statements based on our best information.]
Question continues on back of this page
Based on his argument, the speaker then draws the following conclusions:
There is no doubt that the increase in destructive hurricanes striking the United States
over the last two years is directly caused by global warming since we know that
hurricanes need warm ocean water to form. Furthermore, we can expect to see increases
in both the number and strength of hurricanes in the Atlantic Ocean and worldwide as sea
surface temperatures continue to rise as a result of global warming.
Comment on the validity of the speaker’s conclusions. (Note: I am looking for a
sensible discussion. There is not a single correct answer, but I will check that you
mention and discuss a few specific points.)
(b) Refer to the diagram below to help answer this question. If conditions are favorable,
a tropical depression (weak area of surface low pressure over tropical oceans) can
strengthen into a hurricane. In class we discussed a simplified strengthening process via
a positive feedback loop. Fill in or explain the missing information as requested:
 Describe the surface wind flow near the surface low pressure area. Does this
wind pattern force rising or sinking air motion near the low?
 Hurricanes are called warm core systems because the column of air above the surface
low pressure area is warmer than the air surrounding the warm column. Explain how
the warm core develops.
 Explain how the warm core results (or causes) relatively high pressure to be
found at the top of the troposphere above the surface low.
 Explain why the answer to multiple choice questions (27 and 28) would act to
strengthen hurricane force winds in the lower troposphere. (see hint below)
 Hint for multiple choice questions (27 and 28): you can use the pressure pattern
drawn below to determine where divergence and convergence are occurring.
(Diagram available under OLD EXAMS link on course homepage)