Upper Level Winds Flashcards

1
Q

Cold air - pressure
reduces slowly/ quickly

A

Quickly

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2
Q

Warm air pressure
reduces slowly/quickly

A

Slowly

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3
Q

To be a jet stream, the wind has to be greater than blank knots.

A

70

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4
Q

Whats the jet stream ratio for depth width and length?

A

1:100:1000

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5
Q

What two jet streams are seasonal?

A

Tropical easterly and arctic front

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6
Q

What is the height and speed of the polar front jet?

A

30,000 150-20kts

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7
Q

What is the height and speed of the sub tropic jet? N

A

40,000 150kts

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8
Q

What is the height and speed of the sub tropic jet? S

A

40,000 80-90kts

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9
Q

Below the JS core,
temperature colder/harmer when
flying into the polar air

A

Colder

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10
Q

Above the JS core,
temperature colder/warmer when
flying towards polar air

A

Warmer

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11
Q

Polar front jet lies closer to the blank front than the blank front.

A

Cold - warm

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12
Q

What is the season, altitude and speed of the arctic front jet?

A

January 20000 80kts

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13
Q

What is the season, altitude and speed of the tropical eastily jet?

A

Summer 50,000 90kts

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14
Q

The most severe
CAT is found near
the frontal zone,
especially at the
higher levels on the
cold/warm side and just
above/below the core

A

Cold - below

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15
Q

Jet streams have to be X kts to be displayed on a significant weather chart.

A

80

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16
Q

Low level jet streams are located between x and x feet.

A

500 and 5000ft

17
Q

From summer to winter the average geographic position of the polar front jet stream over the North Atlantic moves.. towards the north/south and the speed increases/decreases.

A

South increases

18
Q

Jet streams’ altitudes:
-blank Jetstream = 20,000ft
-blank Jetstream = 30,000ft
-Sub-blank Jetstream = 40,000ft
-blank Jetstream = 50,000ft

A

Jet streams’ altitudes:
-Arctic Jetstream = 20,000ft
-Polar Jetstream = 30,000ft
-Sub-tropical Jetstream = 40,000ft
-Equatorial Jetstream = 50,000ft

19
Q

Which of the following is correct regarding a warm anticyclone? It increases/decreases in intensity at higher altitudes.

A

Increases

20
Q

Therefore, in the Northern Hemisphere, wind veers/backs with decreasing altitude (meaning that winds will veer/back as we climb through the friction layer).

A

Back then veer

21
Q

What is the approximate speed of a 40-knot wind, expressed in m/s?

A

20ms

22
Q

An aircraft is approaching an airfield when the pilots notice that the headwind is becoming increasingly a crosswind from the right less than 4 500 ft above the airfield. What hemisphere does this occur in?

A

Southern

23
Q

Near the surface, friction increases/decreases the wind speed, this which directly increases/decreases the Coriolis force.

A

Decreases

24
Q

Strongest clear air turbulence is to be expected.. on the cold/warm side of the jet-stream.

A

Cold

25
Q

The north-south horizontal blank gradient at the polar front is the main reason for the formation of the polar front jet stream,

A

Tempurature

26
Q

PGF = CF + Centrifugal Force in a high/low

A

Low

27
Q

CF = PGF + Centrifugal Force in a high/low

A

High

28
Q

The Centrifugal Force acts in the same direction as the PGF ⇒ Increasing wind speed. Therefore, for the same isobar spacing, gradient wind speed in a HIGH is less/greater than the equivalent geostrophic wind.

A

Greater

29
Q

In the Northern Hemisphere and over oceans, the surface wind backs by Xº from the geostrophic wind and speed reduces to blank% of the geostrophic wind.

A

10 degrees 70%

30
Q

In the Northern Hemisphere and over land, the surface wind backs by Xº compared to the geostrophic wind and speed is reduced by C%.

A

30degrees. 50%

31
Q

What is the minimum speed for a wind to be classified as a jet stream?

A

70kts

32
Q

Which force causes the surface wind, in the northern hemisphere, to deflect to the left compared to the geostrophic wind? (Pressure gradient/frictional/Coriolis/centrapetal)

A

Frictional

33
Q

During a flight you enter a zone of lee waves which causes moderate turbulence. You decide to continue the flight and try to avoid the standing waves by: increasing/decreasing speed whilst flying parallel/perpendicular to the mountains,

A

Decreasing and perpendicular

34
Q

What occurs when the isobars are curved?

A

Geostrophic wind.

35
Q

Distinguish between katabatic and anabatic winds. The anabatic wind flows upslope and is weaker/stronger compared to the katabatic wind, which flows _____.

A

Weaker downslope

36
Q

Coriolis Force (CF) - is the force caused by the rotation of the earth. It is directly proportional to the sine of what?

A

Latitude

37
Q

For a given pressure gradient force, the geostrophic wind speed blank as latitude decreases.

A

Increases

38
Q

During the cruise at FL270, on a northerly heading from Paris to London, there is a strong crosswind from the right. Which of the following statements is correct regarding the aircraft’s altitude?

A

Increases