Weather

85問 • 2年前

問題一覧

The primary cause of all changes in the Earth's weather is

variation of solar energy received by the Earth's regions

Which force, in the Northern Hemisphere, acts at a right angle to the wind and deflects it to the right until parallel to the isobars?

Coriolis

What relationship exists between the winds at 2,000 feet above the surface and the surface winds?

The winds at 2,000 feet tend to parallel the isobars while the surface winds cross the isobars at an angle toward lower pressure and are weaker

Winds at 5,000 feet AGL on a particular flight are southwesterly while most of the surface winds are southerly. This difference in direction is primarily due to

friction between the wind and the surface

What causes surface winds to flow across the isobars at an angle rather than parallel to the isobars?

Surface friction

An air mass is a body of air that

covers an extensive area and has fairly uniform properties of temperature and moisture

A characteristic of the stratosphere is

relatively small changes in temperature with an increase in altitude

A jet stream is defined as wind of

50 knots or greater

The average height of the troposphere in the middle latitudes is

37,000 feet

The strength and location of the jet stream is normally

weaker and farther north in the summer

Which feature is associated with the tropopause?

Abrupt change in temperature lapse rate

Which weather phenomenon is always associated with the passage of a frontal system?

A wind change

Which is a characteristic of low-level wind shear as it relates to frontal activity?

With a warm front, the most critical period is before the front passes the airport

Frontal waves normally form on

slow moving cold fronts or stationary fronts

Where do squall lines most often develop?

Ahead of a cold front

Which are characteristics of an unstable cold air mass moving over a warm surface?

Cumuliform clouds, turbulence, and good visibility

What are the characteristics of stable air?

Poor visibility, steady precipitation, and stratus-type clouds

What type clouds can be expected when an unstable air mass is forced to ascend a mountain slope?

Clouds with extensive vertical development

Which is a characteristic of stable air?

Stratiform clouds

The general characteristics of unstable air are

good visibility, showery precipitation, and cumuliform-type clouds

What type of clouds will be formed if very stable moist air is forced up slope?

Stratified clouds with little vertical development

Steady precipitation, in contrast to showers, preceding a front is an indication of

stratiform clouds with little or no turbulence

What enhances the growth rate of precipitation?

Upward currents

Which of the following combinations of weather producing variables would likely result in cumuliform-type clouds, good visibility, rain showers, and possible clear-type icing in clouds?

Unstable, moist air, and orographic lifting

What determines the structure or type of clouds which form as a result of air being forced to ascend?

The stability of the air before lifting occurs

Stability can be determined from which measurement of the atmosphere?

Ambient lapse rate

What are some characteristics of unstable air?

Turbulence and good surface visibility

Unsaturated air flowing up slope will cool at the rate of approximately (dry adiabatic lapse rate)

3°C per 1,000 feet

What feature is associated with a temperature inversion?

A stable layer of air

Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high?

Smooth air and poor visibility due to fog, haze, or low clouds

A temperature inversion will normally form only

in stable air

A common type of ground or surface based temperature inversion is that which is produced by

ground radiation on clear, cool nights when the wind is light

Which conditions are favorable for the formation of radiation fog?

Clear sky, little or no wind, small temperature/dew point spread, and over a land surface

What situation is most conducive to the formation of radiation fog?

Warm, moist air over low, flatland areas on clear, calm nights

The most frequent type of ground- or surface-based temperature inversion is that produced by

radiation on a clear, relatively still night

What types of fog depend upon a wind in order to exist?

Advection fog and up slope fog

In what localities is advection fog most likely to occur?

Coastal areas

In which situation is advection fog most likely to form?

An air mass moving inland from the coast in winter

Fog is usually prevalent in industrial areas because of

an abundance of condensation nuclei from combustion products

Which weather condition can be expected when moist air flows from a relatively warm surface to a colder surface?

Fog

Under which condition does advection fog usually form?

Moist air moving over colder ground or water

The amount of water vapor which air can hold largely depends on

air temperature

Clouds, fog, or dew will always form when

water vapor condenses

To which meteorological condition does the term "dew point" refer?

The temperature to which air must be cooled to become saturated

Which conditions result in the formation of frost?

Temperature of the collecting surface is below the dewpoint of surrounding air and the dewpoint is colder than freezing

What are the four families of clouds?

High, middle, low, and those with extensive vertical development

Which family of clouds is least likely to contribute to structural icing on an aircraft?

High clouds

The presence of standing lenticular altocumulus clouds is a good indication of

very strong turbulence

The suffix "nimbus", used in naming clouds, means a

rain cloud

Standing lenticular clouds, in mountainous areas, indicate

turbulence

Which clouds have the greatest turbulence?

Cumulonimbus

A high cloud is composed mostly of

ice crystals

Fair weather cumulus clouds often indicate

turbulence at and below the cloud level

What are the requirements for the formation of a thunderstorm?

Sufficient moisture, an unstable lapse rate, and a lifting action

What is an indication that downdrafts have developed and the thunderstorm cell has entered the mature stage?

Precipitation begins to fall from the cloud base

Which procedure is recommended if a pilot should unintentionally penetrate embedded thunderstorm activity?

Set power for recommended turbulence penetration airspeed and attempt to maintain a level flight attitude

Which thunderstorms generally produce the most severe conditions, such as heavy hail and destructive winds?

Squall line

Which weather phenomenon is always associated with a thunderstorm?

Lightning

During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts?

Dissipating

If squalls are reported at your destination, what wind conditions should you anticipate?

Sudden increases in wind speed of at least 16 knots rising to 22 knots or more, lasting for at least 1 minute

What is indicated by the term "embedded thunderstorms"?

Thunderstorms are obscured by massive cloud layers and cannot be seen

Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?

The start of rain at the surface

Which is true regarding the use of airborne weather-avoidance radar for the recognition of certain weather conditions?

The radarscope provides no assurance of avoiding instrument weather conditions

In which meteorological environment is aircraft structural icing most likely to have the highest rate of accumulation?

Freezing rain

Test data indicate that ice, snow, or frost having a thickness and roughness similar to medium or coarse sandpaper on the leading edge and upper surface of an airfoil can

reduce lift by as much as 30 percent and increase drag by 40 percent

Which precipitation type normally indicates freezing rain at higher altitudes?

Ice pellets

What is an operational consideration if you fly into rain which freezes on impact?

Temperatures are above freezing at some higher altitude

What temperature condition is indicated if wet snow is encountered at your flight altitude?

The temperature is above freezing at your altitude

The presence of ice pellets at the surface is evidence that

there is freezing rain at a higher altitude

Why is frost considered hazardous to flight operation?

Frost causes early airflow separation resulting in a loss of lift

If the air temperature is +8 °C at an elevation of 1,350 feet and a standard (average) temperature lapse rate exists, what will be the approximate freezing level?

5,350 feet MSL

What is an important characteristic of wind shear?

It is an atmospheric condition that may be associated with a low-level temperature inversion, a jet stream, or a frontal zone

A pilot reporting turbulence that momentarily causes slight, erratic changes in altitude and/or attitude should report it as

light turbulence

What is an important characteristic of wind shear?

It may be associated with either a wind shift or a wind speed gradient at any level in the atmosphere

Where can wind shear associated with a thunderstorm be found? Choose the most complete answer

On all sides of the thunderstorm cell and directly under the cell

Where does wind shear occur?

With either a wind shift or a wind speed gradient at any level in the atmosphere

Hazardous wind shear is commonly encountered near the ground

during periods of strong temperature inversion and near thunderstorms

An aircraft that encounters a headwind of 45 knots, within a microburst, may expect a total shear across the microburst of

90 knots

Maximum downdrafts in a microburst encounter may be as strong as

6,000 feet per minute

What is the expected duration of an individual microburst?

Seldom longer than 15 minutes from the time the burst strikes the ground until dissipation

When penetrating a microburst, which aircraft will experience an increase in performance without a change in pitch or power?

The aircraft in position 3 will experience which effect in a microburst encounter?

Strong downdraft

What effect will a microburst encounter have upon the aircraft in position 4?

Strong tailwind

How will the aircraft in position 4 be affected by a microburst encounter?

Performance decreasing with a tailwind and downdraft

If involved in a microburst encounter, in which aircraft positions will the most severe downdraft occur?

3 and 4

B777 - Part 5

Angelo Ortiz · 50問 · 3年前

B777 - Part 5