WX201 - TEST 2

What transfers heat upwards into the atmosphere?

Thermals PreviousNext

Another term for isobaric chart is constant pressure chart.

True

Compressional heating is the main source of warmth for a Chinook wind.

True

Generally, the smaller the pure water droplet, the lower the temperature at which it will freeze.

True

Heavy showers usually fall from cumulus clouds, whereas steady precipitation normally falls from stratus clouds.

True

In large weather systems, we see that mesoscale circulations have a longer duration than microscale circulations.

True

Not all jet streams form at the tropopause.

True

Santa Ana winds warm by compression as they flow down an elevated desert plateau.

True

The atmosphere is normally the most stable in the early morning and the most unstable in the afternoon.

True

The average winds aloft are the strongest in winter.

True

The difference in surface wind speed between morning and afternoon is typically greater on a clear, sunny day than on a cloudy, overcast day.

True

The polar front jet stream is stronger in winter than in the summer.

True

Over land and also over the ocean, wind gusts are caused by ____.

Turbulent eddies

The Coriolis force is a(n) ____ created by Earth's rotation.

apparent force

The pressure gradient force is directed from higher pressure towards lower pressure ____.

at all places on Earth

Conditional instability occurs whenever the environmental lapse rate is ____ the moist adiabatic rate and the dry adiabatic rate.

between

In a sky filled with scattered cumulus humilis clouds, rising motions are found under the clouds and sinking motions are found ____ the clouds.

between

In a sky filled with scattered cumulus humilis clouds, rising motions are found under the clouds and sinking motions are found ____ the clouds?

between

On a weather map of the Northern Hemisphere, the steadily blowing trade winds would be observed ____.

blowing from tropical high-pressure belts to the low-pressure zone at the equator

On the eastern side of the Rocky Mountains, chinook winds are driest when ____.

clouds form and precipitation falls on the upwind side of the mountains

When a sea breeze moving west meets a sea breeze moving east, they form a ____.

sea breeze convergence zone

The surface pressure at the bases of warm and cold columns of air are equal. Air pressure in the warm column of air will ____ with increasing height ____, in the cold column.

decrease; more slowly than

An altimeter measures altitude but is calibrated to indicate pressure.

False

An important factor in the production of rain by the collision-coalescence process is the number of ice crystals in the cloud.

False

An increase in either the mass or the velocity (or both) produces a decrease in momentum.

False

Generally, the concentration of condensation nuclei is greater over the oceans than over land.

False

The environmental lapse rate is almost always the same as the adiabatic rate.

False

The general circulation of the atmosphere represents the actual air flow around the world and not just an average.

False

The pressure gradient force is non-existent at the equator.

False

In the winter, you read in the newspaper that a large section of the Midwest is without power due to downed power lines. Which form of precipitation would most likely produce this situation?

Freezing rain

Because of ____, surface winds move more slowly than winds aloft with the same pressure gradient.

Friction

Which of the following might be mistaken for hail because of its appearance and its origin?

Graupel

Inversions that form as air slowly sinks over a large area are called ____ inversions. They sometimes occur at the surface, but more frequently, they are observed aloft and are often associated with large high-pressure areas because of the sinking air motions associated with these systems.

subsidence

The atmosphere is normally most stable in the late afternoon and most unstable in the early morning.

temperature changes in a rising or descending parcel of unsaturated air

The dry adiabatic rate is the rate at which ____.

temperature changes in a rising or descending parcel of unsaturated air

A sea or land breeze is caused by ____.

temperature differences

The ultimate cause of jet streams is ____.

the energy imbalance between high and low latitudes

If we closely examine the pattern of general circulation in the three-cell model, areas of surface low pressure should be found at ____.

the equator and 60 degrees latitude

In the Northern Hemisphere, air found to the north of the polar front is ____, whereas air farther south is ____.

cold; warm

The elevation where clouds form is called the ____ level.

condensation

Clouds and precipitation are frequently found on the downwind side of a large lake. This would indicate that the air on the downwind side is ____.

converging and rising

If upper-level divergence exceeds surface convergence, the air pressure at the center of the surface low will ____.

decrease

The winter monsoon in eastern and southern Asia is characterized by ____.

dry weather and winds blowing from land to sea

Thermal turbulence above the surface such as in a desert valley during the summer is usually most severe ____.

during maximum surface heating

The rate at which the actual air temperature changes with increasing height above the surface is referred to as the ____ rate.

environmental lapse

When the ____ is between the moist adiabatic rate and the dry adiabatic rate, it creates a situation known as a conditionally unstable atmosphere.

environmental lapse rate

. The speed of falling cloud droplet increases until the air resistance ____

equals the pull of gravity

An afternoon sky full of cumulus humilis clouds with little vertical growth indicates ____ weather.

fair

An example of orographic clouds would be clouds ____.

forming on the windward slope of a mountain

The wind's speed generally increases with height above Earth's surface because ____.

friction with Earth's surface slows the air near the ground

An offshore wind blows ____.

from land to water

Dust devils ____.

generally form on clear, hot, dry days

Clouds are complex and can have different temperature zones. The region of a cloud where only ice particles exist is called ____.

glaciated

For sub-freezing temperatures, the saturation vapor pressure just above a liquid water surface is ____ the saturation vapor pressure above an ice surface.

greater than

Isobaric surfaces are ____ in less-dense, warm air and ____ in cold, more-dense air.

higher; lower

The jet stream flows ____.

in a wavy pattern from west to east

During the summer along the coast, a sea breeze is usually the strongest and best developed ____.

in the afternoon

Particularly in desert valleys, thermally generated eddies typically peak ____ when surface heating processes are most amenable.

in the afternoon

As an air parcel aloft moves northward from the equator, it moves closer to Earth's axis of rotation. Because of the conservation of angular momentum, the air parcel's motion should ____.

increase in speed

Near the equator, the northeast trades converge with the southeast trades to form the ____.

intertropical convergence zone

During the summer in humid climates, nighttime clouds tend to form over water during a ____.

land breeze

The nighttime counterpart of the sea breeze circulation is called ____.

land breeze

The magnitude of the Coriolis force varies with wind speed and ____.

latitude

In a conditionally unstable atmosphere, the environmental lapse rate will be greater than the moist adiabatic rate and ____ the dry adiabatic rate.

less than

A ____ is generally associated with trough on an upper level isobaric chart.

low pressure center

The rate at which the temperature changes inside a descending (or rising) parcel of saturated air is called the ____ rate.

moist adiabatic

Because of the larger frictional drag in the water, ocean currents move ____ the prevailing winds above.

more slowly than

The intertropical convergence zone (ITCZ) is often known of as the doldrums or the calms, and totally dreaded by pirates and merchant sailors alike, is a region where ____.

northeast trades converge with the southeast trades

The world's deserts are found at 30 degrees latitude because ____.

of the sinking air of the subtropical highs

There are many types of precipitation. Let's think about the typical, however. A typical raindrop is about ____ than a typical cloud droplet.

one hundred times larger

Forced lifting along a topographic barrier is called ____.

orographic uplift

Forced lifting along a topographic barrier is called ____?

orographic uplift

Surface winds move ____ the center of a high-pressure area.

outwards (diverge) from

A small volume of air is referred to as a ____.

parcel of air

In the three-cell model, the wind belt observed on the poleward side of the polar front is called the ____.

polar easterlies

The ____ jet is known to show seasonal variations. In winter, the winds are stronger, and the jet moves farther south as the leading edge of the cold air can extend into subtropical regions, as far south as Florida and Mexico. In summer, the jet is weaker and is usually found over more northerly latitudes.

polar-front

The unit of ____, most commonly found on a surface weather map, is millibars or hectopascals.

pressure

Warm air aloft is associated with constant pressure surfaces that are found at higher altitudes than normal and higher than normal atmospheric ____ aloft.

pressure

Air that ____ vertical displacements is considered to be stable.

resists

A(n) ____ on an upper-level isobaric chart indicates higher-than-average heights.

ridge

In the middle latitudes, when an area of high pressure approaches a city, surface pressure usually ____. When it moves away, pressure usually ____.

rises; falls

In all seasons, the largest amount of latent heat gets released in a ____ parcel of ____ saturated air.

rising; warm

Wind movement near mountains can be quite complex. For example, eddies that form both close to the mountain and beneath each wave crest are called ____.

rotors

Conditional instability depends on the condition of ____.

saturation

The main difference between a cloud drop and a raindrop is its ____.

size

In a fact that surprises many people, small raindrops fall ____ large raindrops, and have ____ terminal velocity than/as large raindrops.

slower than; a lesser

Condensation onto hygroscopic nuclei is possible at relative humidity less than 100 percent due to the ____.

solute effect

There are annual patterns in the movement of jet streams, meaning that the position of the Pacific high over the North Pacific Ocean shifts ____ in winter and ____ in summer.

southward; northward

Inversions that form as air slowly sinks over a large area are called ____ inversions.

subsidence

A wind rose indicates ____.

the percentage of time that the wind blows from different directions.

Upwelling is ____.

the rising of cold water from below

If Earth's surface was homogeneous (either all land or all water), ____.

the semipermanent highs and lows would disappear altogether

For a layer of altostratus clouds to change into altocumulus it is necessary for ____.

the top part of the cloud deck to cool while the bottom part warms

Both the polar front jet stream and the subtropical jet stream are found at which level of the atmosphere?

the tropopause

The land/sea breeze, lake breeze, and mountain/valley breeze are examples of ____ generated by pressure gradients produced by differential heating.

thermal circulations

Updrafts are responsible for the production of hail, while sleet is produced from a different process. Raindrop production can be complex, particularly with the collision-coalescence process. If you observe large raindrops hitting the ground, you could probably say that the cloud overhead was ____ and had ____ updrafts.

thick; strong

If rising air cools ____, the relative humidity becomes 100 percent.

to the dew-point temperature

If an air parcel is given a small push upwards and it continues to move upwards on its own accord, the atmosphere is said to be ____.

unstable

Chinook winds are typically found in the interior west of North America where the Canadian prairies and the Great Plains parallel mountain ranges. The winds can be described as ____.

warm, dry downslope winds

If we look at atmospheric patterns and circulation of the atmosphere, we can situate Chicago, Illinois (latitude 42 degrees N) in the ____.

westerlies

The summer monsoon in eastern and southern Asia is characterized by ____.

wet weather and winds blowing from sea to land

What is an example of microscale motion?

winds blowing past a chimney

The north-south temperature contrast along the polar front is strongest in ____ and weakest in ____.

winter; summer

A station at an altitude of 900 m (about 3,000 feet) above sea level measure, with an air pressure of 930 mb would have a sea level pressure of ____.

1,020 mb

Rising air will eventually cool to its dew-point temperature. At that point, what is its relative humidity?

100

What is considered to be the standard sea-level atmospheric pressure in millibars?

1013.25 mb

Which environmental lapse rate represents the most unstable atmosphere in a layer of unsaturated air?

11 degrees Celsius per 1,000 m

The subtropical jet stream is usually found between ____.

20 degrees to 30 degrees latitude, 200-mb level

In terms of the three-cell general circulation model, the driest regions of Earth should be near ____.

30 degrees latitude and the polar regions

While the diameter of raindrops can vary widely, most that reach Earth's surface are seldom larger than ____ in diameter.

5 mm

____ appearing in the sky indicates that the mid-level of the troposphere is becoming more unstable.

Altocumulus castellanus

Which condition would be described as the most stable, independent of the season or the location on Earth?

An inversion

What is a serious hazard to aircraft which often occurs without any warning, on a bright, clear, weatherless day?

Clear-air turbulence

The ____ force acts at a 90-degree angle to the wind.

Coriolis

A geostrophic wind is a wind that results from a balance between the ____ force and the ____ force.

Coriolis; pressure gradient

Which of the following is not a mechanism primarily responsible for most clouds observed?

Differences in air pressure caused by a rapidly increasing moist adiabatic rate in a thermal.

The quietest time of the day, with the least wind usually occurs during the ____, when thermal turbulence above the surface is normally at a minimum.

Early Morning

A jet stream transfers more heat across the globe when it is zonal.

False

Air pressure decreases with height more rapidly in warm air than in cold air.

False

Areas over the ocean in which weak pressure gradients lie in the center of a high producing weak winds, are commonly referred to as Dog Days latitudes.

False

At any given time, only one jet stream, which is a fast flowing, narrow, meandering current, can be found in the atmosphere. Jet streams are tracked by meteorologists because they always have a dampening effect on the intensity of winds aloft.

False

Because lows are also known as cyclones, the flow of air around them is often called anti-cyclonic flow.

False

If a city receives 24 inches of snow, it is the equivalent to 18 inches of rain.

False

In a cloud composed of water droplets and ice crystals, the saturation vapor pressure is less over the droplets than over the ice.

False

Large, heavy snowflakes are associated with moist air and temperatures well below freezing.

False

Microscale circulations range from a few kilometers to about a hundred kilometers in diameter.

False

Most of the United States is located within the prevailing easterly wind belt.

False

Prevailing offshore winds in summer carry moisture, cool air, and fog into coastal regions, whereas prevailing onshore breezes carry warmer and drier air into the same locations.

False

Sinking air sometimes cools adiabatically.

False

Subsidence has no effect on atmospheric stability.

False

The Coriolis force is the force that causes the wind to blow.

False

The atmosphere is normally most stable in the late afternoon and most unstable in the early morning?

False

The combination of warming the surface and warming the air aloft creates the greatest atmospheric stability

False

Which of the following produces the strongest Coriolis force?

Fast winds; High latitude

In the three-cell model of the atmosphere, the circulation of wind in the atmosphere is driven by the rotation of the earth and the incoming energy from the sun. Each hemisphere has a cell: the Hadley cell, the Ferrel cell, and the polar cell, but most motion occurs in the ____.

Hadley cell

The large convection cell that is driven by convective "hot" towers (a tropical cumulonimbus cloud that reaches out of the troposphere into the stratosphere, which can have rotating updrafts) along the equator is the ____.

Hadley cell

Surface winds are generally strongest and most gusty ____.

In the afternoon

A pilot enters the weather service office (one of 122 that the National Weather Service operates) and wants to know what time of the day she can expect to encounter the least turbulent winds at 760 m (2,500 feet) above central Kansas. If you were the weather forecaster, what would you tell her?

In the early morning

Which statement describes the polar front jet stream?

It forms near the boundary called the polar front.

Which of the below determines the height of a wave generated in the open ocean?

Length of time the wind blows over the water

____ is a condition in which the environmental lapse rate is equal to the dry adiabatic rate.

Neutral stability

The force that would cause a stationary parcel of air to begin to move horizontally, is called the ____.

Pressure Gradient force

Which statement below best describes the curvature effect?

Reduced surface tension and the larger saturation vapor pressure required for the drop to remain in equilibrium with its surroundings.

A wind reported as having a direction of 225 degrees would be a wind blowing from the ____.

SW

Most thunderstorms do not extend very far into the stratosphere because the air in the stratosphere is ____.

Stable

Phenomena on the ____ scale can span over 1000s of kilometers and last for many days. Mid-latitude cyclones, hurricanes, and fronts are examples of this scale of weather events.

Synoptic

Which below best describes the solute effect?

The water droplets dissolve hygroscopic nuclei and condensation can occur at relative humidity less than 100 percent.

A conditionally unstable atmosphere is stable with respect to unsaturated air and unstable with respect to saturated air.

True

A valley breeze develops its maximum strength in the early afternoon because they occur when warm air rises up the sides of the valley.

True

Atmospheric conditions that produce sleet differ from those that produce hail because for sleet to form, surface temperatures must be below freezing, whereas surface temperatures are typically well above freezing during hailstorms.

True

Clear air turbulence often occurs near a boundary of high wind shear.

True

If Earth did not rotate, the wind would blow directly from regions of high pressure toward regions of low pressure.

True

In a cloud over land, where the air temperature is -10 degrees Celsius, we would find many more cloud droplets than ice crystals.

True

In the general circulation of the atmosphere, one would find the region called the doldrums, at the equator.

True

Net convergence of air would cause surface pressure to increase and net divergence would cause surface pressure to decrease.

True

Off the southeast coast of the United States, the Bermuda high is a major semipermanent subtropical high, that influences weather patterns in North America.

True

Off the west coast of the United States, the Pacific high is a major semipermanent subtropical high that influences weather patterns in North America.

True

Pilots must be aware that turbulent eddies can occur in conjunction with mountain waves, which may extend upwards into the stratosphere. When these huge eddies develop in clear air, this form of turbulence is referred to as clear air turbulence.

True

Stationary storm systems, centered somewhere over the open sea, are capable of creating large waves with wave heights measuring over 31 m (100 feet).

True

The angle at which surface winds cross isobars is, to a large degree, dependent on the roughness of the terrain.

True

The polar front is a boundary separating cold polar air to the north from warm subtropical air to the south, the greatest contrast in air temperature occurs along the frontal zone.

True

The polar front jet stream can affect weather as far south as Florida and Mexico.

True

The pressure gradient force has a direct effect on horizontal wind movements.

True

The temperature of rising air at a given level inside a cumulus cloud is normally warmer than the air around the cloud.

True

The ultimate cause of jet streams is the energy imbalance that exists between high and low latitudes

True

Typical cloud droplets seldom reach the ground as rain because they evaporate before reaching the ground.

True

We can generally expect the air to be rising above areas of surface low pressure and sinking above areas of surface high pressure.

True

When wind encounters a solid barrier such as a mountain, hill, or dune, a whirl of air, called an eddy, forms on the object's leeward side.

True

Rain that falls from a cloud but evaporates before reaching the ground is referred to as ____. One can see streaks in the sky, and it often has a lovely color.

Virga

The majority of the United States lies within this wind belt.

Westerlies

What is an example of mesoscale motion?

Winds blowing through a city.

Precipitation with the greatest size (diameter) is ____.

a hailstone

Found in certain regions of the cloud formation, a supercooled cloud droplet is ____.

a liquid droplet observed at temperatures below 0 degrees Celsius (32 degrees Fahrenheit)

According to the three-cell general circulation model, at the equator, we would not expect to find ____.

a ridge of high pressure

If the environmental lapse rate is less than the moist adiabatic rate, the atmosphere is ____.

absolutely stable

The growth of a precipitation particle by the collision of an ice crystal (or snowflake) with a supercooled liquid droplet is called ____.

accretion

In the Northern Hemisphere, the polar jet stream is strongest when ____.

air north of the polar front is much colder than air south of the polar front

On a 500 mb chart, contour lines are drawn to represent horizontal changes in ____, which correspond to horizontal changes in ____.

altitude; pressure

Altocumulus clouds that show vertical development and produce tower-like extensions are called ____.

altocumulus castellanus

The ____ that occurs over a given horizontal distance, is called the pressure gradient.

amount of pressure change

A rising parcel of air that does not exchange heat with its surroundings is an example of ____.

an adiabatic process

An air parcel in an unstable atmosphere has ____ force acting on it.

an upward-directed

On a weather map of the Northern Hemisphere, one would observe the westerlies ____.

between the subpolar lows and the subtropical highs