Exam 4: Atmospheric Humidity

Which of the following will increase in a rising parcel of air?

A strand of human hair is known to increase by 2.5 percent as the relative humidity increases from 0 to 100 percent.

During the great Chicago heat wave of July 1995 the afternoon air temperature reached 106 degrees Fahrenheit at Midway Airport, followed by an overnight low temperature of only 84 degrees Fahrenheit. Many residents either had no air conditioning or could not afford to use it. More than ____ deaths occurred over five days.

Why are specific humidity and mixing ratio more commonly used in representing atmospheric moisture than absolute humidity? What is the only way to change the specific humidity or mixing ratio of an air parcel?

A region can have a high specific humidity and low relative humidity because large amounts of water vapor in the air and very high air temperatures will cause the specific humidity to be high, but the relative humidity to be low.

Explain why, at temperatures below freezing, the saturation vapor pressure over water is greater than the saturation vapor pressure over ice.

Condensation occurs primarily when air is cooled, because as temperature drops the speed of the water molecules increases.

Water in a glass will evaporate more quickly on a windy, warm, dry summer day than on a calm, cold, dry winter day.

As the air temperature increases, with no addition of water vapor to the air, the relative humidity will ____________________.

Under saturated conditions, for every molecule that evaporates, one must condense, and no net loss of liquid or vapor molecules results.

Condensation differs from precipitation, because during precipitation water vapor is removed from the atmosphere, whereas during condensation solid or liquid water is removed from the atmosphere.

Chicago and many other cities in the United States have added neighborhood ____________________ and taken other steps to address the danger of heat waves.

This instrument uses a human or horse hair, or a synthetic fiber, to measure relative humidity.

Comparing the three phases of water, molecules in the solid phase (ice)have the slowest vibrational speed, and molecules in the gaseous phase (water vapor)have the highest vibrational speeds.

The specific humidity and ____ of an air parcel remain constant as long as water vapor is not added to or removed from the parcel.

Using the concept of supercooled water, explain why ice cubes sometimes feel "sticky" when taking them out of the freezer.

The psychrometer is used to obtain ____ and ____.

Sun's energy transforms enormous quantities of liquid water into water vapor in a process called ____.

Which of the following is the BEST indicator of the actual amount of water vapor in the air?

The ____ determines the amount of water vapor in the air by measuring the air's actual water vapor pressure.