Deck 4: Moisture and Atmospheric Stability

Question 1

Which type of lifting mechanism results from warm air lifting over cold air?

A) orographic lifting
B) frontal wedging
C) convective lifting
D) convergence

Answer 1

B

Question 2

Relative humidity depends on the water vapor present in the air and the:

A) pressure.
B) air temperature.
C) altitude.
D) latitude.
E) dew point.

Answer 2

B

Question 3

Which of the following will NOT cause air to become more unstable?

A) forceful lifting of air
B) intense solar heating which warms the air from below
C) upward movement caused by general convergence
D) subsidence of an air column

Answer 3

D

Question 4

$?=\frac{\text { mass of water vapor (grams) }}{\text { mass of dry air (kilograms) }}$ The formula shown above defines the humidity measure known as:

A) the mixing ratio.
B) relative humidity.
C) vapor pressure.
D) absolute humidity.

Question 5

For the following questions, refer to the diagram shown below.


-In the diagram shown above, the parcel would have a temperature of __________when it reached the base on the leeward side of the mountain.

A) 20°C
B) 35°C
C) 25°C
D) 15°C

Question 6

The stability of the air layer close to the earth's surface can vary markedly. Much of this variation is caused by:

A) changes in wind speed.
B) changes in heating or cooling of the surface.
C) changes in pressure.
D) changes in wind direction.

Question 7

If the environmental lapse rate is less than the wet adiabatic lapse rate, then the atmosphere is:

A) absolutely unstable
B) absolutely stable.
C) conditionally unstable
D) cannot determine from this information.

Question 8

What is necessary in order for clouds to form when the atmosphere is absolutely stable?

A) an environmental lapse rate less than 5°C
B) a lifting mechanism other than convection (such as a front)
C) a high degree of subsidence
D) cooling of the air mass from below

Question 9

If your environmental lapse rate is 17 C/km on a partly cloudy afternoon, then the atmosphere is said to be:

A) absolutely unstable.
B) conditionally unstable.
C) absolutely stable.

Question 10

-Refer to the diagram of a simple parcel above. What would the mixing ratio be if the volume were to double?

A) 5 g/m³
B) 2.5 g/kg
C) 20 g/m³
D) The mixing ratio would remain unchanged.

Question 11

The air in Great Falls, Montana has a temperature of 5°C and a relative humidity of 50%. On the same afternoon, the air in Palm Springs, California has a temperature of 25°C and a relative humidity of 50%. What can be said about the amount of vapor in the air at these two cities?

A) Great Falls and Palm Springs will have the same vapor content.
B) Palm Springs will have a higher vapor content than Great Falls.
C) Great Falls will have a higher vapor content than Palm Springs.

Question 12

A wet- bulb thermometer and a dry- bulb thermometer are both parts of which meteorological instrument?

A) a sling psychrometer
B) a barometer
C) an anemometer
D) a thermistor

Question 13

-Refer to the diagram of a simple parcel above. What additional information would you need in order to be able to calculate the relative humidity of this parcel?

A) current vapor pressure inside the parcel
B) temperature outside of the parcel
C) air pressure inside the parcel
D) current temperature/capacity to hold water vapor inside the parcel

Question 14

A__________ is an instrument used to measure humidity.

A) aquimeter.
B) hydrometer.
C) hygrometer.
D) humidimeter.

Question 15

The atmosphere is most unstable when the temperature of the air ______ with height.

A) decreases slightly
B) drops rapidly
C) is uniform
D) increases rapidly
E) increases slightly

Question 16

Which of the following is a good explanation for why dew tends to form in the grass at night?

A) Temperatures of the objects near the ground often cool below the dew point at night.
B) More water vapor is present at night.
C) The atmosphere cannot form clouds at night.
D) Pressure is greatest then.

Question 17

If your environmental lapse rate is 7 C/km on a partly cloudy afternoon, then the atmosphere is said to be:

A) conditionally unstable.
B) absolutely stable.
C) absolutely unstable.

Question 18

Refer to the diagram of a simple parcel above. What is the absolute humidity of this parcel?

A) 2 g/m³
B) 0.2 g/kg
C) 10 g/m³
D) 5 g/kg

Question 19

In which phase do water molecules have the lowest kinetic energy?

A) liquid
B) ice
C) vapor
D) It has the same kinetic energy in all three phases.

Question 20

Water's temperature increases slowly because some of the energy absorbed is used to instead of to____________ increase the kinetic energy of the molecules.

A) break hydrogen bonds
B) decrease the motion of the water molecules
C) decrease the specific heat of the water
D) create hydrogen bonds

Question 21

The attractive forces between the hydrogen atoms in one water molecule and the oxygen atoms in another molecule are known as:

A) hydrogen bonds.
B) dark forces.
C) liquid bonds.
D) water bonds.

Question 22

Which of these pairs of processes, working together, will make the atmosphere most unstable?

A) warm the surface and warm the air aloft
B) cool the surface and warm the air aloft
C) warm the surface and cool the air aloft
D) cool the surface and cool the air aloft

Question 23

An adiabatic process is one in which the:

A) altitude of the air parcel remains constant.
B) pressure on the air parcel remains constant.
C) work done is zero.
D) temperature remains constant.
E) heat exchanged with the surroundings is zero.

Question 24

The two changes of state that are the most important part of the water cycle for the atmosphere would be:

A) condensation, freezing.
B) melting, freezing.
C) melting, sublimation.
D) evaporation, condensation.
E) condensation, melting.

Question 25

The change in the actual air temperature as you go up into the atmosphere is called:

A) conversion.
B) diffusion.
C) latent heat.
D) convergence.
E) environmental lapse rate.

Question 26

The stability of an air layer refers to its:

A) albedo.
B) overall density.
C) pressure as measured at its base.
D) tendency to either sustain or suppress upward vertical motions.

Question 27

As liquid water is evaporated into the atmosphere, heat energy is:

A) given off by the water vapor.
B) absorbed by the evaporating water.
C) absorbed by the remaining liquid.
D) absorbed by the surrounding air.
E) released by the evaporating water.

Question 28

During the process of adiabatic cooling, the temperature decreases because the air has:

A) lost heat to the colder air at higher altitudes.
B) expanded to a larger volume.
C) lost some of its water vapor.
D) emitted infrared radiation.
E) been compressed.

Question 29

A cold air mass that is warmed at its base from contact with the warm ground will have its lapse rate:

A) compressed.
B) changed to an inversion.
C) remain constant.
D) decreased.
E) increased.

Question 30

Saturation is best defined as:

A) a vapor pressure greater than 1000 mb.
B) a mixing ratio of at least 100 g/kg.
C) equal numbers of water molecules evaporating from and condensing into a water surface.
D) the point when water molecules completely stop evaporating from a water surface.

Question 31

Relative humidity indicates the:

A) actual amount of water in the air.
B) chance of cloud formation.
C) nearness to saturation for the air.
D) chance for evaporation of water.
E) probability of precipitation.

Question 32

For the following questions, refer to the diagram shown below.

Given the conditions shown in the diagram above, the elevation of the cloud base would be:

A) 2000 m.
B) 2500 m.
C) 111000 m.
D) 3000 m.

Question 33

The amount of water vapor in the air (by volume) usually does not exceed:

A) 100 percent.
B) 40 percent.
C) 4 percent.
D) 14 percent.
E) 28 percent.

Question 34

-Refer to the diagram of a simple parcel above. What would the absolute humidity be if the volume were to double?

A) 2.5 g/m³
B) 20 g/m³
C) 5 g/m³
D) The absolute humidity would remain unchanged.

Question 35

All of the following are properties that make water unique among other substances on Earth EXCEPT:

A) water does not participate easily in hydrogen bonding.
B) water exists naturally in all three phases (solid, liquid, vapor) and changes easily from one to another.
C) water is able to store large quantities of heat.
D) water's solid phase is less dense than its liquid phase.

Question 36

Which of the following processes requires the HIGHEST RELEASE of energy from the water molecules?

A) condensation
B) freezing
C) deposition
D) melting

Question 37

$?=\frac{\text { mass of water vapor (grams) }}{\text { volume of air (cubic meters) }}$ The formula shown above defines the humidity measure known as:

A) relative humidity
B) absolute humidity
C) the mixing ratio
D) vapor pressure

Question 38

An increase in the environmental lapse rate of an air layer results in the layer becoming:

A) an air parcel.
B) less stable.
C) more stable.
D) cooler.
E) heavier.

Question 39

If the air temperature remains constant, evaporating water into the air wil_____l the dew point and___________ the relative humidity.

A) decrease, decrease
B) increase, decrease
C) increase, increase
D) not change, increase
E) decrease, increase

Question 40

For the following questions, refer to the diagram shown below.

In the diagram shown above, the temperature and dew point at the peak (4000 m) would be: (Assume 100% relative humidity and a wet adiabatic lapse rate of 5°C/km.)

A) both equal to - 5°C.
B) equal to - 5°C and - 10°C, respectively.
C) both equal to - 15°C.
D) equal to - 15°C and - 5°C, respectively.

Question 41

Assume that the actual vapor content of the air remains constant over the course of a day. How does the relative humidity at 2:00 p.m. probably compare to the relative humidity at 5:00 a.m.?

A) The relative humidity at 2:00 p.m. is higher.
B) The relative humidity is the same at 2:00 p.m. as at 5:00 a.m.
C) The relative humidity at 2:00 p.m. is lower.

Question 42

Transpiration is:

A) the movement of groundwater under Earth's surface.
B) the type of bond that holds water molecules together.
C) the return of water to the oceans via rivers.
D) the process by which plants release water into the atmosphere.

Question 43

All of the following are lifting mechanisms in the atmosphere EXCEPT:

A) divergence.
B) frontal wedging.
C) orographic.
D) convection.

Question 44

These two conditions, working together, will make the atmosphere the most unstable.

A) cool the surface and cool the air aloft
B) warm the surface and warm the air aloft
C) warm the surface and cool the air aloft
D) cool the surface and warm the air aloft

Question 45

The moist adiabatic rate is different from the dry adiabatic rate because:

A) saturated air is always unstable.
B) a parcel of saturated air weighs less than a parcel of unsaturated air.
C) latent heat is released inside a parcel of rising saturated air.
D) unsaturated air is always stable.
E) an unstable air parcel expands more rapidly.

Question 46

In order to have significant snowfall accumulation, dew points must generally be above:

A) 10°F.
B) 0°F.
C) 32°F.
D) - 10°F.

Question 47

Water vapor constitutes about this much of the atmosphere by volume.

A) 0- 4 percent
B) 0- 100 percent
C) 0- 12 percent
D) 4- 12 percent
E) 4- 25 percent

Question 48

Assume that a parcel with an initial temperature of 20°C and a dew point of 7°C starts at sea level and travels up the side of a mountain. At what elevation will condensation begin inside the parcel?

A) 2600 meters
B) 1400 meters
C) 2700 meters
D) 1300 meters

Question 49

Frost that forms on cold glass is created by the process of:

A) transpiration.
B) sublimation.
C) freezing.
D) deposition.

Question 50

The vertical motions that occur when the air is unstable are termed:

A) convection.
B) geostrophic.
C) subsidence.
D) convergence.
E) cyclonic.

Question 51

A convergence of winds near the surface is associated with cloud production because it:

A) increases the wind speed.
B) increases the lapse rate.
C) forces the air to rise.
D) increases the dew point.
E) creates a vortex or spiral pattern.

Question 52

The capacity of the air to hold water vapor:

A) increases with an increase in temperature.
B) increases with an increase in pressure.
C) increases with a decrease in temperature.
D) decreases with an increase in temperature.

Question 53

A stable atmosphere is one in which:

A) upward vertical motions are resisted.
B) temperatures are adiabatic.
C) rising bubbles of air accelerate upward.
D) clouds are forming.

Question 54

The property which primarily controls how much water can be present as a gas is:

A) amount of dry air gases present.
B) availability of latent heat.
C) water's specific heat.
D) temperature of the air.
E) number of particulates present.

Question 55

The temperature of rising air parcels__________as they move upward.

A) increases
B) remains constant
C) decreases
D) may either increase or decrease

Question 56

During a clear, relatively calm day, the relative humidity will tend to ________from sunrise to early afternoon.

A) increase
B) decrease
C) remain nearly steady

Question 57

Which of the following requires the GREATEST RELEASE of latent heat energy into the atmosphere?

A) condensation of 1 gram of water
B) evaporation of 1 gram of water
C) melting of 1 gram of water
D) freezing of 1 gram of water

Question 58

Why does a rising air parcel cool off?

A) It is unstable.
B) It expands.
C) It loses heat to its surroundings.
D) It loses energy by radiation.
E) Its relative humidity is less than 100 percent.

Question 59

The most important process of cloud formation in the atmosphere is:

A) cooling by expansion of air.
B) radiation cooling.
C) cooling by release of latent heat of vaporization.
D) cooling by compression of air.

Question 60

Which of the following would NOT be associated with stable atmospheric conditions?

A) afternoon thunderstorms
B) widespread fog
C) buildup of pollutants
D) temperature inversion

Question 61

That part of the total atmospheric pressure attributable to its water vapor content is termed__________
.

Question 62

To make a decision about the stability of the air, what is the most important information that you need to know beyond the temperature and dew point of the rising parcel?

Question 63

When the dry and wet bulb temperatures measured by a psychrometer are equal, all but one of the following is true. Which one is FALSE?

A) The air is saturated.
B) Relative humidity is 100 percent.
C) A rise in temperature would cause condensation.
D) Water vapor content is at a maximum.

Question 64

The instrument consisting of a wet bulb thermometer and a dry bulb thermometer is termed a _________.

Question 65

Thermals are created by the lifting mechanism known as ____________.

Question 66

An inversion represents an extremely stable atmosphere because a parcel of air that rises into an inversion will eventually become______ and ______ dense than the air surrounding it.

A) warmer, less
B) colder, more
C) colder, less
D) warmer, more

Question 67

The heat released when water vapor condenses to form a cloud or when liquid droplets freeze in a cloud:

A) adds water to the cloud.
B) makes the air heavier.
C) helps the cloud to rise higher.
D) evaporates more water.
E) cools off the cloud.

Question 68

As the temperature of air is reduced to its dew point, which of these is most likely to occur?

A) supercooling
B) freezing
C) condensation
D) melting
E) evaporation

Question 69

An air parcel rises over a mountain and cools adiabatically. Which lifting mechanism has acted on this parcel?

A) convective lifting
B) convergence
C) frontal wedging
D) orographic lifting

Question 70

Plants release water to the atmosphere through the process of __________.

Question 71

Adiabatic processes are only important for air:

A) that is saturated.
B) masses which remain near the earth's surface.
C) that is polluted.
D) which is rising or sinking.
E) that is stagnant.

Question 72

Why is the wet adiabatic rate of cooling less that the dry adiabatic rate?

Question 73

-Refer to the diagram of a simple parcel above. What is the mixing ratio of this parcel?

A) 2 g/m³
B) 10 g/m³
C) 0.2 g/kg
D) 5 g/kg

Question 74

If you have enough energy to melt 1 gram of ice and then change it to vapor, then you also have enough energy to complete what other phase change for the same gram of ice?

Question 75

A large negative environmental lapse rate would occur in a layer with:

A) cold air above, warm air below.
B) warm air above, cold air below.
C) uniformly warm temperatures throughout.
D) uniformly cold temperatures throughout.

Question 76

Sinking or subsiding air cannot form clouds due to the:

A) removal of water vapor.
B) release of latent heat.
C) formation of unstable layers.
D) warming temperatures.
E) loss of particulates.

Question 77

About what percent of Earth's water can be found in the oceans?

A) 97%
B) 70%
C) 90%
D) 53%

Question 78

What is the most frequent cause of the air becoming saturated?

Question 79

List two atmospheric phenomena in air near the surface that are likely when the air is very stable.

Question 80

Once precipitation has fallen on land, it may take one of three paths. List these three possible routes.