GY 101: Chapter 4

Which of the following are settings in which fog is formed due to the cooling of near-surface air?

- Air cools as it moves up the slope of a mountain - Warm air moves over a cold glacier - A quickly cooling surface at night cools the air above it

Match the air mass with the amount of cooling necessary in order to reach its dew-point temperature.

- Air mass 1--- relative humidity 15%: Has to cool the most in order to reach its dew point - Air mass 2--- relative humidity 60%: Has to cool a moderate amount in order to reach its dew point - Air mass 3--- Relative humidity 90%: Has to cool the least in order to reach its dew point

Which of the following phrases correctly describe cirrus clouds?

- Are wispy in appearance - Occur high in the troposphere

Which of the following two describe the movement of water molecules between a solid and a vapor?

- Deposition - Sublimation

Which of the following factors affect measurements of specific humidity?

- Evaporation - Precipitation

Which parts of the United States are the most foggy?

- Great Lakes region - Pacific Northwest - New England - Gulf Coast

Which of the following explain the high specific humidity of the atmosphere in the tropics?

- High amount of evaporation - Warm air

Which of the following describe lapse rate?

- Is measured in C/km - Is the temperature change experienced by a moving parcel of air for a given change in elevation.

Which of the following correctly describe vapor pressure?

- Is symbolized by e - Increases with increasing number of water molecules - Is represented in millibars

What happens to a parcel of saturated air as it rises in the atmosphere?

- It cools - Water vapor condenses, freezes, and is deposited - It releases heat

What happens to a rising parcel of air?

- Its temperature decreases - Its volume increases

How does urbanization affect local atmospheric stability?

- Light-colored materials increase albedo. - Dark-colored materials decrease albedo.

Match the process to the correct direction and states of matter involved between ice and the liquid and gaseous states of water.

- Melting: Solid to Liquid - Freezing: Liquid to Solid - Deposition: Gas to Solid - Sublimation: Solid to Gas

Which of the following describe the effects of deforestation on local atmospheric stability?

- Shading is reduced, and more insolation is used to heat the ground. - Less transpiration occurs, which results in less water (and heat) added to the atmosphere.

Which of the following best describe unsaturated air conditions?

- The air contains less water vapor than it is able to hold - The weather is likely fair

Which of the following best describe saturated air conditions?

- The weather is likely cloudy and/or foggy - The air contains as much water vapor as it is able to hold

How does a warm ocean surface current influence the overlying atmosphere?

- These conditions create a steep environmental lapse rate. - Warm air created by the water will rise adiabatically if warmer than the surrounding air and cause an unstable atmosphere, forming clouds and rain.

Match the region to the correct seasonal pattern of specific humidity.

- Tropics: Highest humidity year-round - Poles: Lowest humidity year-round - Southern Hemisphere: High humidity in January, low humidity in July - Northern Hemisphere: Low humidity in January, high humidity in July

Characterize the different air stability conditions.

- Unstable Air: Rising air, whether saturated or unsaturated, is warmer than the surrounding air and continues to rise. - Conditionally Unstable Air: Rising air will either continue to rise if it is saturated or cease rising if it is unsaturated. - Stable Air: Rising air is cooler than the surrounding environment and has a tendency to sink.

What factors are used to classify clouds?

- What their form is -What altitude they exist at - Whether they are related to precipitation

Distinguish the different types of cumulus clouds. 1) Cirrocumulus 2) Altocumulus 3)Stratocumulus 4) Cumulonimbus

1) Lumpy, wispy clouds high in the atmosphere composed almost entirely of ice. 2) Mid-level clouds that contain both liquid water and ice particles. 3) Low clouds in discrete layers composed of tiny liquid water drops. 4) Tall clouds composed of liquid near their base and ice neat their top.

Match the setting to the description of how fog is formed there from the cooling of near-surface air. 1)Fog forms as a quick drop in surface temperatures causes near-surface air temperatures to drop to the dew point and become saturated. 2) Fog forms from the lateral movement of warm air over a cold surface; the warm air cools to the dew point. 3) Fog forms as air is forced uphill due to wind forming a cloud along the surface.

1) Radiation 2) Advection 3) Upslope

Match the way in which air rises due to interaction with the land surface with the correct words that complete the description. 1) Wind may _____ due to friction with the land surface, causing air behind it to pile up and rise. 2) Air on different sides of a mountain may _____ during the day, causing it to rise and converge at the summit. 3) Low-level winds may encounter a mountain, causing them to slow down, _____, and rise.

1) Slow down 2) Warm up 3) Pile up

Match the cloud forms to their appropriate descriptions. 1) Cumuliform 2) Stratiform 3) Cirriform

1) Taller than wide; lumpy 2) One or more layers 3) Feathery; wispy

Match the type of fog to the general location where it is commonly formed. 1) Advection fog 2) Evaporation fog 3) Radiation fog

1) Where cold ocean currents extend into warm coastal areas 2) Over the open oceans 3) Over the polar ice caps

Below are listed factors that are important to the formation of fog in certain settings. Match the factor to why it is important. 1) Brings moist or dry air into an area. 2) Contributes abundant moisture to the air. 3) Controls temperatures and influences air movement. 4) Is the typical moisture condition of an area. 5) Is a reflection of latitude and influences temperature.

1) Wind 2) Proximity to big water 3) Topography 4) Humidity 5) Climate

Which of the following is a measure of specific humidity?

10 g/kg

Given the following relative humidities of different air masses, which has to cool the least in order to reach its dew point?

85%

Why does dew typically form in the evening?

Air cools in the evening, and cold air holds less moisture than warm air, causing the vapor to condense.

What happens when two air masses collide?

Air is forced upward, as an air mass is an obstacle.

What is the primary difference between an adiabatic and diabatic parcel of air?

An adiabatic parcel does not exchange energy with its surroundings, whereas a diabatic parcel does.

What is the primary result of a decrease in energy, such as cooling, on the molecules moving between the liquid and vapor states?

An increase in condensation

What is the primary result of an increase in energy, such as heating, on the molecules moving between the liquid and vapor states?

An increase in evaporation

The hydrogen atoms in a water molecule are arranged...

Asymmetrically

Water-vapor _____ is the maximum amount of water air can hold.

Capacity

Dew forms when air becomes _____ and can no longer hold the same amount of water vapor as it did previously.

Cool

Saturated air _____ as it rises in the atmosphere. Some of the water vapor changes state, condenses or freezes and releases _____ to the surrounding environment.

Cools; Heat

The arrival of a front is often accompanied by precipitation because the difference in, ________, caused by differences in temperature, between the two air masses causes the warmer one to rise, which then cools adiabatically and quickly reaches the dew point.

Density

Water vapor beings to condense at a temperature called the _____ point when a given volume of air becomes saturated.

Dew

A rising parcel of air exchanges energy with its surrounding is _____, whereas a parcel of air that does not exchange energy with its surroundings is _____.

Diabatic; Adiabatic

Why does southeastern Asia experience such a dramatic change in seasonal humidity?

During the summer, the winds switch direction and bring warm, moist air from the ocean.

Fog that forms when cold air encounters a warm lake does so due to.....

Evaporation

_____ commonly forms in the autumn, when cool air rises and incorporates water vapor produced by an underlying warm water body, quickly reaching saturation.

Evaporation fog

True or False: A weather forecast that includes precipitation means that it is going to rain.

False

True or False: Dew-point temperatures are highest in the winter in the United States.

False

True or False: Liquid water molecules have more energy, in general, than molecules of water vapor.

False

Ground-level clouds are called _____.

Fog

Free convection results from air rising due to unstable conditions, whereas _____ convection is air rising due to external factors.

Forced

Clouds are classified based on their _____ and _____, and whether or not they are associated with precipitation.

Form; Altitude

Unstable air rises due to _____ convection whereas air forced to move because of external factors does so due to forced convection.

Free

Moving air masses may encounter surface irregularities, causing the front of the mass to slow down due to ______ ; the back of the mass starts to pile up, resulting in the air rising.

Friction

Absolute humidity is a measure of how much water vapor is in a given volume of air and is measured in _____ per cubic meter.

Grams

Ice cover and cold temperatures in _____ latitudes result in low specific humidities at the poles.

High

Water molecules in the air tend to have _____ energy levels compared to liquid water molecules.

Higher

Water has a relatively high specific heat capacity, which means that it.....

Holds heat well

The amount of water vapor in the atmosphere is called....

Humidity

The two _____ atoms in a water molecule are arranged asymmetrically.

Hydrogen

Cirrus clouds are composed of _____ as they are located very high in the troposphere. They are also easily blown about by strong winds at these levels, so they have a wispy appearance.

Ice

A parcel of air that does not gain or lose energy to its surroundings will _____ in volume and _____ in temperature as it rises in the atmosphere.

Increase; Decrease

Measured in units of degrees per vertical distance, the _____ rate is a measure of how much a rising parcel of air cools for a given rise in elevation.

Lapse

The rate at which the air surrounding an adiabatically moving air parcel changes temperature with height is called the environmental _____ rate.

Lapse

Global patterns of specific humidity vary primarily due to....

Latitude

Deforestation exposes more soil to incoming solar radiation, which results in more heating of the ground, less transpiration, and _____ energy stored as latent heat in the local atmosphere.

Less

The general trend of dew-point temperatures in the United States during the winter is _____ dew points in the north that get _____ to the south.

Low; Higher

The saturation level of air in a cloud next to an ice crystal can be reached _____ if the air were next to a drop of liquid water.

More easily than

What is urbanization?

Natural land cover is replaced with concrete, asphalt, and buildings.

Condensation _____ are tiny particles that are necessary for the formation of water droplets in a cloud.

Nuclei

The phenomenon that occurs when low-level air encounters a mountain and rises is called the _____ effect.

Orographic

What is the name for the process by which water, ice, or some combination of water and ice falls from the sky?

Precipitation

What type of fog is formed when precipitation falls through lower, colder air and evaporates, increasing the humidity and causing the cold air to reach its dew point?

Precipitation fog

_____ humidity is usually represented by a percentage and is the ratio of how much water vapor is in the air relative to the maximum amount of water vapor that air can hold.

Relative

Water exists in which forms in the atmosphere?

Solid, Liquid, and Gas

Which area of the world shows a drastic change in seasonal humidity due to a significant change in wind direction that brings warm, moist air from the ocean, resulting in summer monsoon conditions?

Southeastern Asia

The mass of water vapor in a body of air compared to the total mass of that air is _____ humidity.

Specific

Which of the three types of cloud forms listed is layered and comes from the Latin word for "to stretch"?

Stratiform

In which season are dew-point temperatures highest in the United States?

Summer

Of the U.S. areas listed, which is the least foggy?

The Southwest

Humidity is the term used to describe...

The amount of water vapor in the atmosphere

Which of the following describes relative humidity?

The ratio of the amount of water vapor in the atmosphere compared to the water vapor capacity

What is the dew point?

The temperature at which a volume of air becomes saturated with water vapor

What is the environmental lapse rate?

The temperature change with height undergone by air surrounding an adiabatically moving air parcel.

The thermal qualities of water and land are often compared. Water has a higher specific heat capacity and more _____ inertia than land does, which means that it can hold more heat and its temperature is not readily changed by outside influences such as the Sun.

Thermal

Why are condensation nuclei necessary for the formation of water droplets in a cloud?

They provide very small particles on which water droplets can condense.

In how many different forms does water exist in the atmosphere?

Three

What are condensation nuclei?

Tiny particles around which water droplets in clouds form.

True or False: Absolute humidity changes as air expands or contracts in the atmosphere.

True

True or False: Fog is just a low-level cloud.

True

True or False: The primary factor controlling global patterns of specific humidity is latitude.

True

True or False: Urbanization can either increase or decrease the albedo of an area.

True

Air next to a liquid drop of water in a cloud is _____, so water molecules will move from the drop to the surrounding air and _____ relative humidity.

Unsaturated; Increase

_____ air continues to rise due to its warmth, unconditionally unstable air may either rise or sink, depending on saturation level, and _____ rising air is likely to sink.

Unstable; Stable

What is the name of the process through which natural land cover is replaced by asphalt, concrete, and buildings?

Urbanization

The amount of atmospheric pressure contributed by the weight of water vapor in the atmosphere is known as _____ pressure.

Vapor

A warm ocean current that travels to higher latitudes will likely _____ the overlying air, causing it to _____ and create clouds and precipitation.

Warm; Rise

When two air masses of different temperatures meet, the _____ mass is forced upward.

Warmer and less dense

The maximum amount of water vapor that air can hold is called...

Water-Vapor Capacity

Specific humidity will only change if _____ ______ is added or subtracted through the processes of evaporation and condensation.

Water; Vapor

What is the orographic effect?

When surface air encounters a mountain and flows upward

When two air masses collide, air is forced upward....

Whether it is stable or unstable

Factors that are important for the formation of fog in an area include not only the overall climate, temperature, and humidity conditions, but also the prevailing _____ direction and whether a location is close to a large body of _____.

Wind; Water