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60 terms


The property which primarily controls how much water can be present as a gas is
temperature of the air.
Relative humidity indicates the
nearness to saturation for the air.
As liquid water is evaporated into the atmosphere, heat energy is
absorbed by the evaporating water
During a clear, relatively calm day, the relative humidity will tend to _______ from sunrise to early afternoon.
Evaporation is a process which tends to keep temperatures cooler where it occurs. This is because evaporation
uses energy to change the phase of water instead of warming it.
The heat released when water vapor condenses to form a cloud or when liquid droplets freeze in a cloud
helps the cloud to rise higher.
The most common reason why dew forms on the grass at night is that
temperatures are coolest in the grass.
Relative humidity depends on the water vapor present in the air and the
A convergence of winds near the surface is associated with cloud production because it
forces the air to rise
When water vapor condenses, the heat involved
is released to the nearby air.
Sinking or subsiding air cannot form clouds due to the
warming temperatures.
If the air temperature remains constant, evaporation water into the air will ______ the dew point and _______ the relative humidity.
increase, increase
The capacity of the air to hold water vapor
increases with an increase in temperature.
The two changes of state that are the most important part of the water cycle for the atmosphere would be
evaporation, condensation.
As the temperature of air is reduced to its dew point, which of these is most likely to occur?
Why does a rising air parcel cool off?
it expands
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 rise in temperature would cause condensation
The amount of water vapor in the air (by volume) usually does not exceed:
4 percent.
If air at sea level with a temperature of 27 degrees C is forced up a mountain slope and the air's dew point at the condensation level is 14 degrees C, at what elevation will condensation begin?
1300 meters
The moist adiabatic rate is different from the dry adiabatic rate because:
tent heat is released inside a parcel of rising saturated air.
If your environmental lapse rate is 7 C/km on a partly cloudy afternoon, then the atmosphere is said to be:
absolutely stable.
If your environmental lapse rate is 17 C/km on a partly cloudy afternoon, then the atmosphere is said to be
absolutely unstable
An inversion represents an extremely stable atmosphere because a parcel of air that rises into an inversion will become _____ and _____ dense than the air surrounding it.
colder, more
The atmosphere is most unstable when the temperature of the air ____ with height.
drops rapidly
These two conditions, working together, will make the atmosphere the most unstable.
warm the surface and cool the air aloft
The lapse rate of an air layer next to the ground is strongly influenced by
heating or cooling of the ground.
The buoyancy of a raising air parcel is greatly affected by
heat released if water vapor condenses.
During the process of adiabatic cooling, the temperature decreases because the air has
expanded to a larger volume.
The stability of the air layer close to the earth's surface can vary markedly. Much of this variation is caused by
Changes in heating or cooling of the surface
A cold air mass that is warmed at its base from contact with the warm ground will have its lapse rate
Dew is most likely to form on
clear calm nights
It is raining on only one side of your street. The cloud above you is
You are flying in an airplane at 36,000 feet above sea level. You see lightning outside your plane window. The cloud that is close by is
Which of these is a mid-level cloud?
The necessary conditions for hail formation include strong upward vertical motion and
large numbers of supercooled droplets.
The most common way for air to be cooled in order that a cloud may form is by
rising and expanding.
Why do clouds represent a source of heat for the atmosphere?
Cloud formation releases latent heat to the air.
Clouds which have extensive vertical dimensions are
the important difference between liquid droplets and ice crystals in a supercooled cloud is that ice crystals
grow much more rapidly
The cloud droplets in a cloud are formed by water vapor molecules and
condensation nuclei.
The conditions that persist along the West Coast of the U. S. that are conducive to fog formation are
moist air moving over a cold surface.
Clouds and precipitation form in the air primarily due to
air being cooled as it rises
The water content or volume of a raindrop is approximately ____ times that of a typical
cloud droplet.
1 million
Which of these clouds is least likely to produce precipitation that reaches the ground?
Supercooled water is water which is
still liquid at temperatures below 0 degrees C.
Why are high altitude clouds always so thin?
Very little water vapor is present
Freezing rain (ice storm) or sleet occurs when
upper air is warm and surface air is cold.
Clouds are classified and named according to their altitude and
form or appearance
The most important process for cloud formation in the atmosphere is
cooling by expansion of the air.
Clouds, dew and frost all form because air has become saturated. This condition of saturation
is usually caused by
the air being cooled.
Hail is most commonly associated with:
cumulonimbus clouds.
When warm moist air moves over a cold surface, ______ fog may result.
This cloud sometime produces mare's tails
The ______ cloud may have an "anvil head."
Thunder and lightning are associated with the cloud.
A(n) _______ is a layer of dark gray clouds that produces precipitation.
A halo around the Sun or the Moon indicates the cloud ______ is present
The most common source of cloud condensation nuclei is
combustion by-products
Relative humidity in cities is usually ______ compared to rural areas.
On which day of the week would someone living in or downwind of a city expect the least precipitation (on the average)?