ATMO 336 – Section 001           Name__________________________

Exam 1 – Spring 2006

 

Write all answers on the answer sheets.  Mark your answers clearly.  If we cannot determine your answer, it will be marked wrong.  You will turn in both the exam sheets and the answer sheets.  Write your name on both.

 

Multiple Choice (2 points each)

1.     From the list of gases below, select the two most common gas molecules in Earth’s atmosphere. Circle two answers on the answer sheet.

 

2.     From the list of gases below, select the two that contribute most to the greenhouse effect on Earth. Circle two answers on the answer sheet.

 

Answer Choices for questions 1 and 2

(a)   Carbon dioxide (CO2)                   (d) Ozone (O3)

(b)  Methane (CH4)                              (e) Oxygen (O2)

(c)   Nitrogen (N2)                                (f) Water vapor (H2O)

 

3.     Tiny liquid or solid particles that are suspended in the air are called __________

(a)   carcinogens                                   (c) aerosols

(b)  greenhouse agents                          (d) haze

 

4.     The temperature of the tropopause is ________________ .

(a)   close to the temperature at the Earth’s surface

(b)  much warmer than the temperature at the Earth’s surface

(c)   much colder than the temperature at the Earth’s surface

 

5.     Higher than about 20,000 ft above sea level, people have trouble breathing.  The reason is that _______________ .

(a)   the air pressure and density are too low to get enough oxygen

(b)  the percentage of oxygen molecules in the air drops below 21%

(c)   the air temperature is too cold to breathe

(d)  the ozone levels are too high

 

6.     Immediately after riding up in a high-speed elevator, the eardrum will be pushed ________ before “popping” back into its proper position.

(a)   out away from the brain

(b)  in toward the brain

 

7.     On average, during the winter season, the 500 mb winds over the United States blow in which direction?

(a)   West to East                                  (c) North to South

(b) East to West                                  (d) South to North

 

Use the 500mb map shown at the bottom of this page to answer questions 8-14.  Locate the marked points A-D on the map.  These are the answer choices for 8-12.

 

8.     At which point do you expect the temperature to be the most below average?

9.     At which point do you expect the temperature to be the most above average?

10.  At which point will the 500 mb wind direction be closest to northerly (use the meteorological definition for wind direction)?

11.  At which TWO points will the 500 mb wind speed by greatest (circle two choices)?

12.  At which point would you expect the best chance of precipitation?

13.  The climatological average 500 mb height for Tucson on this day is 5690 meters.  Based on this information and the map below, what weather conditions would you expect for Tucson at this time?

(a)   Clear, with above average temperatures

(b)  Clear, with below average temperatures

(c)   Cloudy and Rainy, with below average temperatures

(d)  Cloudy and Rainy, with above average temperatures

14.  The map corresponds to what local time in Tucson?

(a)   11 PM, Saturday, February 11                  (c) 11 AM, Sunday, February 12

(b)  6 AM, Sunday, February 12                      (d) 1 PM, Sunday, February 12

 

 

15.  Suppose we put some air in a sealed, rigid container, i.e., no air can enter or leave the container and the shape and volume of the container cannot change.  If the air inside is cooled (temperature lowered), what happens to the number density and pressure of the air inside the container?

(a)   Number density remains the same; Air pressure increases

(b)  Number density remains the same; Air pressure decreases

(c)   Number density increases; Air pressure increases

(d)  Number density decreases; Air pressure decreases

 
16.  Salt Lake City, UT is 1320 m (4330 ft) above sea level

Las Vegas, NV is 663 m (2174 ft) above sea level

      Which city will have the lowest station air pressure (i.e., measured with a barometer)?

(a)   Always Salt Lake City

(b)  Always Las Vegas

(c)   Sometimes Salt Lake City, Sometimes Las Vegas

 

17.  Salt Lake City, UT is 1320 m (4330 ft) above sea level

Las Vegas, NV is 663 m (2174 ft) above sea level

      Which city will have the lowest sea level pressure (or equivalent sea level pressure)?

(a)   Always Salt Lake City

(b)  Always Las Vegas

(c)   Sometimes Salt Lake City, Sometimes Las Vegas

 

18.  Winds are caused by ______________ .

(a)   horizontal changes in air pressure

(b)  the rotation of the Earth

(c)   the frictional force between the air and the surface of the Earth

 

19.  Just downstream of 500 mb ridges, there is _______ of air in the upper troposphere which causes ________ vertical air motion in the atmosphere.

(a)   divergence ; sinking                      (c) divergence ; rising

(b)  convergence ; sinking                    (d) convergence ; sinking

 

20.  Which air mass is forced to rise upward near a cold front?  How about near a warm front?

(a)   Cold air mass; cold air mass         (c) Warm air mass; cold air mass

(b)  Cold air mass; warm air mass       (d) Warm air mass; warm air mass

 

21.  Based on the simple model of fronts described in class, if a warm front is producing rain, the rain is most likely falling on the _________ side of the front on the ground.

(a)   cold air mass                                 (b) warm air mass

 

22.  When we look at weather systems from above (using satellite imagery as was shown in class), we see swirling cloud motions that indicate winter-type storms.  These large storm systems rotate _______ in the Northern Hemisphere.

(a)   Clockwise                                     (b) Counterclockwise

 

23.  The polar jet stream is generally found above the position of _________ at an altitude of about _________ .

(a)   a surface cyclone ; 5 km (16,400 ft) above sea level

(b)  a surface cyclone ; 10 km (32,800 ft) above sea level

(c)   the polar front ; 5 km (16,400 ft) above sea level

(d)  the polar front ; 10 km (32,800 ft) above sea level

 

24.  Weather forecast models are not able to make absolutely accurate forecasts.  Which of the following is NOT a reason why?

(a)   There are errors in the initial conditions or the starting state of the model

(b)  The model equations don’t account for everything that happens in the atmosphere, for example, some processes like cloud formation happen at small scales that cannot be represented by the model, i.e., smaller scales than the size of the model grid cells

(c)   Random events happen from time to time, which the model cannot know about

 

25.  Which process requires the most energy?

(a)   Raising the temperature of one gram of ice from -100° C to 0° C

(b)  Melting one gram of ice

(c)   Raising the temperature of one gram of liquid water from 0° C to 100° C

(d)  Evaporating one gram of liquid water

 

26.  Suppose you take a beer can out of a refrigerator that is at a temperature of 37˚ F.  At first, the outside of the can is dry, but then you notice that water condenses on the sides of the can, which of the following is most likely true?

(a)   The air inside the refrigerator is saturated

(b)  The air outside the refrigerator is saturated

(c)   The dew point temperature of the air outside the refrigerator is below 37˚ F

(d)  The dew point temperature of the air outside the refrigerator is above 37˚ F

 

For questions 27-29,  suppose you have an unsaturated parcel of air that contains some water vapor.  If the parcel is warmed, what will happen to:

 

27.  The saturation mixing ratio of the air in the parcel?

(a)   It will decrease in value                (b) It will increase in value

(c) Its value will remain the same

 

28.  The dew point temperature of the air in the parcel?

(a)   It will decrease in value                (b) It will increase in value

(c) Its value will remain the same

 

29.  The relative humidity of the air in the parcel?

(a)   It will decrease in value                (b) It will increase in value

(c) Its value will remain the same

 

 

Temperature

(ºF)

Saturation Mixing Ratio (g/kg)

Temperature

(ºF)

Saturation Mixing Ratio (g/kg)

5

1.21

55

9.32

10

1.52

60

11.19

15

1.89

65

13.38

20

2.34

70

15.95

25

2.88

75

18.94

30

3.54

80

22.43

35

4.33

85

26.48

40

5.28

90

31.16

45

6.40

95

36.56

50

7.74

100

42.78

 

Use the table of saturation mixing ratios to answer questions 30- 31

 

30.  What is the relative humidity of air with a temperature of 80° F and a dew point temperature of 40° F?

(a) 6.6%          (b) 23.5%        (c) 50.0%        (d) 56.1%

 

31.  If the air temperature is 70° F and the relative humidity is 58%, approximately what is the dewpoint temperature?

(a) 40° F          (b) 45° F         (c) 50° F          (d) 55° F

 

32.  When you touch a wooden object that is at a temperature of 50° F it often feels warmer than a metal object that is also at a temperature of 50° F.  The best explanation for this is that __________ .

(a)   wood is a better heat conductor than metal

(b)  metal is a better heat conductor than wood

 

33.  Treatment for a person suffering from hypothermia should include _________ .

(a)   replacing wet clothing with dry clothing

(b)  spraying water on clothing to increase evaporative cooling

 

34.  On a given day, the heat index in Phoenix is higher than it is in Tucson.  Which of the following MUST be true?

(a)   The air temperature in Phoenix is higher than it is in Tucson

(b)  The relative humidity in Phoenix is higher than it is in Tucson

(c)   The dew point temperature in Phoenix is higher than it is in Tucson

(d)  None of the above

 

 

 

 

 

 

 

Short Answer Questions (Select 5 of the 8 Questions) -- 7 Points Each

Write your answers on the attached answer sheets.  If you need more space, please use the back of the multiple choice answer sheet.  Your answers should be short and to the point.  Make sure you answer all parts of each question.  Points will be deducted for incorrect or unnecessary statements in your answer, even if the correct answer is found somewhere.  Be sure to clearly indicate which 5 questions you would like graded.

 

1.     As you move upward in the troposphere,

(a)   Does air pressure increase or decrease?  Briefly explain why.

(b)  Does air number density increase or decrease?  Briefly explain why.

(c)   Does air temperature usually increase or decrease?  Briefly explain why.

2.     With regard to a 500 mb longwave trough, list some of the features to look for in the contour pattern that can help you determine the strength of the trough (i.e., help determine whether or not the trough will force strong divergence in the upper troposphere).  Look at the 500 mb map on the second page of the multiple choice section.  Would you classify the big trough over the United States as strong or weak?  Explain your answer.

3.     Two basic types of low pressure systems are called “cold core lows” and “warm core lows” as shown in the figure below.  In both types the “L” represents a low pressure area at the surface and “colder” and “warmer” compares temperature in the air column above the low with air columns surrounding the low.  In both cases, the change in air pressure along the ground surface causes winds to blow at ground level.  Which type of low will be characterized by winds that get stronger with increasing altitude above the surface and which type will be characterized by winds that get weaker with increasing altitude above the surface?  Explain.

4.     Shown above is a portion of a sea level weather map.  Based on the pattern of isobars, draw arrows at points A and B showing the wind direction.  Does the wind pattern you drew result in divergence, convergence, or neither for the region located between points A and B?   Will this force air to rise, to sink, or neither in a vertical air column located between points A and B?

5.     What is meant by “latent heat”?  Explain how energy is transferred from the Earth’s surface to the middle troposphere by the process of moist convection.

6.     Water is said to boil when the saturation vapor pressure of the water equals the surrounding air pressure.  At sea level water boils at a temperature of 100° C.  Do you expect that water will boil at a higher, lower, or the same temperature on top of a 12,000 ft mountain?  Explain the reason for your answer.  (Hint you need to consider how air pressure changes with increasing altitude and how saturation vapor pressure of water changes with the temperature of the water).

7.     In the lecture notes, it is stated “the lower the relative humidity, the faster the rate of net evaporation.”  This isn’t absolutely true.  More specifically it should be “the larger the difference between the saturation mixing ratio and the actual mixing ratio [i.e., (US – U)], the faster the rate of net evaporation.”  Using the table provided for multiple choice questions (30, 31) determine which of the cities below will have the fastest rate of net evaporation.  The answer is NOT city C, which is the one with the lowest relative humidity.  Provide an explanation for this in your own words.

Location
Air Temperature

Relative Humidity

City A

90° F

50%

City B

70° F

30%

City C

50° F

10%

 

8.     List two strategies used by the human body to keep its core temperature from getting too high under hot conditions and briefly describe how each works.  Explain why one of these strategies won’t work if the air temperature is extremely hot.