Chapter 12

_____ is the process by which liquid water changes into water vapor.

• condensation

• sublimation

• melting

• evaporation

• freezing

Mixing ratio, relative humidity, and dew-point temperature are all ways of measuring the amount of ________ in the air.

• water vapor

• condensation level

• vapor pressure

• convergence

The ________ is the temperature to which a parcel of air would need to be cooled in order to reach saturation.

• water vapor

• dew point

• parcel

• condensation level

Which of the following statements about relative humidity is true?  (Select all that apply.)

• Increasing water vapor content increases relative humidity and increasing temperature decreases relative humidity.

• Increasing wind speed increases relative humidity.

• Increasing altitude will decrease humidity

• Increasing pressure increases relative humidity.

The cooling or warming of air that occurs because air is allowed to expand or is compressed, not because heat is added or subtracted is called ________.

• sensible heat

• wet adiabatic rate

• adiabatic temperature changes

• dry adiabatic rate

What condition is required for cloud formation in the atmosphere?

• A rising parcel of air attains a relative humidity of 50 percent.

• A descending parcel of air reaches its dew-point temperature.

• A rising parcel of air reaches its dew-point temperature.

• A rising parcel of air reaches the edge of Earth’s atmosphere.

• A descending parcel of air reaches Earth’s surface.

How does frontal lifting cause air to rise?

• When warm and cold air masses separate, the warmer, less dense air rises over the cooler, denser air.

• When warm and cold air masses collide, the warmer, less-dense air acts a barrier over which the cooler, denser air rises.

• When warm and cold air masses collide, the cooler, denser air acts a barrier over which the warmer, less-dense air rises.

• When warm and cold air masses collide, the warmer, denser air acts a barrier over which the cooler, less-dense air rises.

• When warm and cold air masses separate, the cooler, denser air rises over the warmer, less dense air.

What is the difference between the environmental lapse rate and adiabatic cooling?

• The environmental lapse rate is caused by an increase in pressure as an air parcel rises; adiabatic cooling is the decrease in temperature with the increase in altitude.

• The environmental lapse rate is caused by a decrease in pressure as an air parcel rises; adiabatic cooling is the decrease in temperature with the increase in altitude.

• The environmental lapse rate is the increase in temperature with the increase in altitude; adiabatic cooling is caused by a decrease in pressure as an air parcel rises.

• The environmental lapse rate is the decrease in temperature with the increase in altitude; adiabatic cooling is caused by a decrease in pressure as an air parcel rises.

• The environmental lapse rate is caused by a decrease in pressure as an air parcel rises; adiabatic cooling is the increase in temperature with the increase in altitude.

Describe the weather associated with unstable air.

• The lifting of unstable air often creates tall, towering clouds with no precipitation.

• The lifting of unstable air often creates overcast days with drizzle.

• The lifting of unstable air often creates overcast days and sometimes tornadoes.

• The lifting of unstable air often creates overcast days, but never creates precipitation.

• The lifting of unstable air often creates thunderstorms and sometimes tornadoes.

What role do condensation nuclei play in the formation of clouds

• Water surrounds condensation nuclei before it condenses into clouds.

• Water surrounds condensation nuclei before it evaporates into clouds.

• Condensation nuclei serve as surfaces for water-vapor condensation high above the ground.

• Condensation nuclei serve as the single center for clouds.

• Condensation nuclei serve as surfaces for water-vapor condensation on the ground.