atpl/oxford/met/ch10 Flashcards
Standing in the Northern Hemisphere, north of a polar frontal depression travelling west to east, the wind will
Continually back
ATC will only report wind as gusting if:
Gusts exceeds mean speed by 10kts
What is a land breeze?
From land over water at night
When heading South in the Southern Hemisphere you experience Starboard drift:
You are flying away from a lower temperature
What is the Bora?
Cold katabatic wind over the Adriatic
Flying from an area of low pressure in the Southern Hemisphere at low altitudes, where is the wind coming from?
Left and slightly on the nose
What causes the Geostrophic wind to be stronger than the gradient wind around a low?
Centrifugal force opposes the gradient force
A large pressure gradient is shown by:
Close spaced isobars - strong winds
Where would you expect to find the strongest wind on the ground in temperate latitudes?
In an area of Low pressure
At a coastal airfield, with the runway parallel to the coastline. You are downwind over the sea with the runway to your right. On a warm summer afternoon, what would you expect the wind to be on finals?
Crosswind from the right
What causes wind?
Difference in pressure
If flying in the Alps with a Föhn effect from the south
Clouds will be covering the southern passes of the Alps
Comparing the surface wind to the 3000ft wind
Surface wind blows across the isobars and is less than the 3000ft wind
90km/hr wind in kts is:
50
The Geostrophic Wind blows at your flight level in Northern Hemisphere the true altitude and indicated altitude remain constant, is the crosswind
No crosswind
With all other things being equal with a high and a low having constantly spaced circular isobars. Where is the wind the fastest?
Anticyclonic
Föhn winds are
Warm descending winds
What is the effect of a mountain valley wind?
it blows down a mountain to a valley at night
What is the difference between Gradient and Geostrophic winds?
Curved isobars and straight isobars
What prevents air from flowing directly from a high to a low pressure?
Coriolis force
Wind is caused by:
Horizontal pressure difference
For the same pressure gradient at 50N, 60N and 40N, the geostrophic wind speed is:
Greatest at 40N
Where are easterly and westerly jets found?
Northern hemisphere only
In high pressure systems:
The winds tend to be stronger in early afternoon.
An aircraft is flying East to West in the Northern Hemisphere. What is happening to his altitude?
If the wind is from the north, he will gain altitude
Where would an anemometer be placed?
10m above aerodrome elevation on a mast
Which of the following is an example of a Foehn wind?
Chinook
Wind at altitude is usually given as …….. in ……..
True, KT
If you fly with left drift in the Northern Hemisphere, what is happening to surface pressure?
Increases
