Chapter 17
To be classified as rain, water droplets that fall from a cloud must be of what minimum diameter?
0.5mm
What is the most precise cause for the adiabatic cooling of a rising parcel of air in the atmosphere?
A decrease in atmospheric pressure.
Which statement most accurately reflects the relationship between dew-point temperature and moisture in Earth's atmosphere?
A high dew point temperature indicates moist air.
While you are watching the television weather report to prepare for your geology field trip tomorrow afternoon, the weather reporter predicts the development of nimbostratus clouds. What equipment should you bring in addition to your hand lens and hammer?
A raincoat.
What condition is required for cloud formation in the atmosphere?
A rising parcel of air reaches its dew-point temperature.
Precipitation in the middle latitudes can be induced by the Bergeron process year round, as long as which condition exists in the atmosphere?
As long as ice crystals can form in the upper parts of cumulonimbus clouds.
Which factor is most significant in the formation of clouds in the atmosphere?
Ascent of parcels of air.
Contrails produced by jet aircraft engines are most similar to which cloud type?
Cirrus.
Which mechanism causing air masses to ascend is significant in the creation of midlatitude hurricanes and cyclones?
Convergence.
Most rainfall originates in which types of clouds?
Cumulonimbus and nimbostratus.
In which cloud type could you observe the activity of both the Bergeron process and the collision-coalescence process on a summer day in the middle latitudes?
Cumulonimbus.
In which cloud type might you expect to find a co-existing mixture of ice crystals and supercooled water?
Cumulonimbus.
Ligtning, thunder, hail, and occasionally tornadoes are associated with which cloud type?
Cumulonimbus.
In the Pacific Northwest, western Washington state receives enough annual precipitation to be classified as rain forest, while eastern Washington is extremely dry. How do such extreme condition exist in the same state?
Easter Washington exists as a rain shadow desert behind the Cascade range.
An air mass moving across a landscape encounters a mountain and is forced up the mountain slope. What happens to the temperature of the air mass as it rises and why?
Temperature decreases because fewer air molecules allow the air mass to expand.
Which of the following scenarios best illustrates the process of sublimation?
Glacial ice converting to water vapor in direct sunlight.
In cross section, concentric layering can be observed in hailstones. How does this type of layering develop?
Hailstones can move up and down in cumulonimbus clouds and with each upward trip, another layer of ice is added.
At which altitude would you expect to observe the formation of cirrostratus clouds?
High altitudes with bases above 6,000 meters.
In the cold cloud conditions necessary for the Bergeron Process to work, what makes up the majority of condensation nuclei?
Ice crystals.
In the middle latitudes during the summer, cirrus clouds are composed of which form of water?
Ice crystals.
In the winter, when warm, tropical air from the Gulf of Mexico moves northwestward, cities like Denver that are situated along the eastern side of the Rocky Mountains tend to get prodigious amounts of snow. What is the cause of these storms?
Orogenic lifting.
Which process results in the dry conditions found in the Great Basin of the western U.S.?
Orographic effect.
When a parcel of air moves upward in the atmosphere, what is the result?
The air in the parcel expands and is cooled adiabatically.
Delicate frostlike accumulations of ice form as supercooled cloud or fog droplets encounter objects and freeze on contact. What do we call this type of precipitation?
Rime.
Which situation produces the flat base of cumulus clouds?
Rising air reaches the dew-point temperature.
Which form of precipitation starts to fall as a liquid but freezes into ice pellets before hitting the ground?
Sleet.
Which of the following is an example of condensation nuclei?
Smoke.
Dendrites, needles, ands sector plates are representative of which type of precipitation?
Snow.
Which fog types are produced by evaporation rather than cooling?
Steam and frontal fogs.
Which type of fog is characterized by cool air moving over warm water, allowing evaporated water from the water surface to cool and condense?
Steam fog.
Which type of fog is produced when you breathe out on a cold winter morning and you can "see your breath"?
Steam fog.
The latent heat of vaporization has the effect of cooling a liquid because __________.
The gas molecules that form and leave the liquid are the higher temperature molecules in the liquid, so the temperature of the liquid is reduced.
In analyzing the layers in a hailstone, you find that some layers are milky white and others are clear. What is the explanation for the color variation in the layers?
The milky white layers are produced by the rapid freezing of tiny droplets on the hailstone that trap air, while the clear layers form when larger droplets collide with it.
At sea level pressure, which best expresses the relationship between temperature and saturation mixing ratio?
The warmer the air, the higher the saturation ratio.
Condensation nuclei, tiny particles of matter in the air, are important because __________.
They provide a surface for water molecules to form on.
Which type of fog is produced when air is lifted over a topographic barrier?
Upslope fog.
On a winter morning you wake to find the trees, sidewalks, roads, and cars in your neighborhood covered with layer of ice. Since the possibility of snow was forecast, what was the cause of the ice glaze?
Water became supercooled a nd froze on contact.
Adiabatic temperature changes result from which of the following conditions in the atmosphere?
When atmospheric temperature change occurs without an accompanying increase or decrease in heat.
In addition to poor visibility and heavy snowfall, blizzard conditions are characterized by which additional parameter?
Wind speeds greater than 56 kph.
