LECTURE QUIZ: Atmospheric Moisture
NAME________________________
PSCI 131
DUE: Tuesday, March 18th
14/WI
15 pts
Write legibly. If I can’t read it, it gets zero points. This quiz does not represent a complete sampling
of material from this chapter that you can expect to see on exams. Answers that, in my judgment,
look too similar to other students’ answers will be considered academic dishonesty and both papers
will receive a zero. Two incidents of academic dishonesty will result in failure of the course. The best
way to avoid this is to do this work on your own.
1. Label each of the following state changes of water as exothermic or endothermic: (1/2 pt each)
a. Freezing
____________________
b. Condensation
____________________
c. Sublimation
____________________
d. Deposition
____________________
2. What is the saturation content of air at the following temperatures? (1/2 pt each)
a. -30º C
_______ g
b. 5º C
_______ g
c. 25º C
_______ g
d. 40º C
_______ g
3. The vapor content of an air parcel is 2.5 g, and its temperature is 5º C. What is the air’s relative
humidity? Show all work below, and include appropriate units. (2 pts)
Relative humidity = ________ %
4. Air’s relative humidity (rises / falls) if the air’s temperature rises. Circle one bolded answer. Assume
constant vapor content.
5. The relative humidity of a parcel of air is 75%, and its temperature is 25 degrees C. What is the air’s
vapor content? Show all work below, and include appropriate units. (2 pts)
Vapor content = ________ grams
6. A parcel of air, whose temperature is 25º C at sea level and whose vapor content is 10 g, rises to an
altitude of 1000 m.
a. Will the parcel be saturated when it reaches 1000 m? YES or NO
b. Condensation will begin when the parcel reaches 1000 m. TRUE or FALSE
7. Which of the following is not true for an air parcel that has reached its condensation level? (Circle only
one answer.)
a. Relative humidity is 100%
b. Condensation can occur
c. It begins to cool at the wet adiabatic rate as it continues to rise
d. It is saturated
e. Vapor content is equal to saturation content within the parcel
f. All of the above are true for air that is at its condensation level
g. A and B are not true
h. C and D are not true
8. The dew point temperature of an air parcel is 10 degrees C. What is the air’s vapor content? Explain
your reasoning. (3 pts)
Vapor content = _________ grams
Reasoning: ____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
9. Which of the following is NOT one of the mechanisms that can force air to rise? (Circle one.)
a. Frontal wedging
b. Orographic lifting
c. Spontaneous expansion
d. Convergence
e. Convective lifting
f. All of the above are mechanisms that can force air to rise
10. Match the following stability types to the correct conditions: (3 pts)
a. Absolute stability
Surrounding air always cools faster than rising parcel
____
b. Absolute instability
Parcel cools faster than surrounding air only as long as
parcel’s relative humidity is less than 100%
____
Parcel always cools faster than surrounding air
____
c. Conditional instability
11. Match each set of conditions with the correct stability type. WAR: wet adiabatic rate. DAR: dry
adiabatic rate. ELR: environmental lapse rate. (3 pts)
a. WAR<ELR<DAR
b. ELR<WAR<DAR
c. WAR<DAR<ELR
absolute instability _____
conditional instability _____
absolute stability
_____