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Flashcards in Mountain Waves Deck (20)
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1

Define mountain waves

Waves or ripples which form in the atmosphere caused by air encountering an obstruction or barrier at the surface of the earth

2

List the 4 factors that affect the evolution of mountain waves

Obstruction
Stable layer
Strong wind
Weak directional shear

3

The wavelength and strength of the vertical currents are affected by:

The width of the obstruction

4

The amplitude and strength of the vertical currents are affected by:

the lee side fall (sudden drop)

5

The waves immediately following the obstruction are the __________

strongest and get progressively weaker

6

A stable layer must be present just ______ the barrier

above

7

The minimum speed at which wind will create a mountain wave i:

25kts

8

An angle of incidence of ____ degrees each side of the barrier is the maximum allowable deviance

30

9

List the 3 cloud types associated with mountain waves:

Cap
Rotor
Lenticular

10

What type of lift creates cap clouds and what dissipates them on the other side?

Orographic lift
Adiabatic heating

11

Rotor clouds form past the obstruction as a result of __________. they appear as ___________

Turbulent mixing
long line of stratocumulus

12

Wave crests may be marked with:

Lenticular clouds

13

lenticular clouds at mid levels are called

ACSL Altocumulus standing lenticular

14

What are the most dangerous element of mountain waves?

Rotor Clouds

15

List the 5 hazards to aviation associated with mountain waves

Wind shear
Obscured terrain
Turbulence
Up/downdrafts
Changes in pressure

16

Downdrafts are most severe:

near a mountain and at about the same height as the top

17

Increased wind speed in the wave crests cause a:

lowering of the pressure (bernouilli)

18

the most turbulent area of in a mountain wave system is:

the rotor

19

Strong vertical wind shears are often concentrated ____________ the jet stream

Just above and below

20

Mountain waves are more pronounced on the __________ side of the jet stream

warm