Clear Air Turbulence and Mountain Waves

Question 1

For mountain waves to form there should be flow of air across the ridge, generally within ……. of the perpendicular to the ridge.

Answer 1

> (a) 30°
(b) 45°
(c) 60°

Question 2

For mountain waves to form the wind speed for small mountains should be at least

Answer 2

(a) 15 m/s
(b) 10 m/s
>(c) 7m/s

Question 3

For mountain waves to form the wind speed for large mountains should be at least

Answer 3

> (a) 15 m/s
(b) 10 m/s
(c) 7m/s

Question 4

For mountain waves to form there should be …… air below the ridge and less stable air above.

Answer 4

> (a) Stable
(b) Unstable
(c) Indifferent

Question 5

The worst kind of turbulence is encountered in the vicinity of ____ clouds.

Answer 5

> (a) Rotar Clouds
(b) Lenticular Clouds
(c) Cap Clouds

Question 6

In Mountain waves the Rotor clouds form in

Answer 6

(a) Troughs
>(b) Ridges
(c) Valley

Question 7

Clear air turbulence is often encountered

Answer 7

> (a)At the boundary of a jet stream
(b)In the wake of a passing airplane
(c)In the wake of a larger airplane at take off and landing
(d) All of the above

Question 8

Most CAT occurs on the …….. of a jet stream and in the vicinity of upper level frontal zones where temperature contrasts are strong.

Answer 8

> (a) Fringes
(b) Within the core
(c) Axis

Question 9

CAT is the bumpiness experienced by aircraft at high altitudes. Over North India its maximum frequency is during :

Answer 9

> (a) Oct - May
(b) Jul - Aug
(c) Jun - Sep

Question 10

When approaching an area where mountain waves have been reported, a pilot should expect:

Answer 10

(a) Possible presence of roll clouds and lenticular clouds
(b) Intense up draughts and down draughts on the lee side of the mountains.
(c) Moderate to severe turbulence as far as 20 to 30 nm from range on leeward side. >(d)All of the above