Atmospheric stability & Cloud Formation

Question 1

Stability is the idea that

Answer 1

What goes up must come down. What doesn’t come down, means it’s unstable.

Question 2

What is the Adiabatic process?

Answer 2

Change of pressure, but without heat or matter entering or leaving the system.

Taking into account WATER in air when ISA doesn’t.

Question 3

Any air that’s below 100% saturation / humidity =

Answer 3

Dry air

Question 4

100% humidity =

Answer 4

100% saturated air

Question 5

DALR (dry air lapse rate) =

Answer 5

1⚫️C per 100m

3⚫️C per 1000ft

Question 6

Saturated air lapse rate (SALR)=

Answer 6

1.8⚫️C per 1000ft

Question 7

Environmental Lapse Rate (ELR) is the…

It is responsible if air is…

Answer 7

Actual decrease of temperature with altitude.

• > ABSOLUTELY UNSTABLE
• > ABSOLUTELY STABLE
• > CONDITIONALLY UNSTABLE

Question 8

Absolutely unstable=

Answer 8

Air keeps on going up

Question 9

Absolutely stable

Answer 9

Air falls back down to ground

Question 10

Conditionally unstable

Answer 10

Depends on ELR lapse rate.

-if it’s in between DALR & SALR

Question 11

If ELR after SALR

Answer 11

ELR IS STABLE

nice weather, stratus cloud, small supercooled water droplets, smooth

Question 12

If ELR before DALR

Answer 12

unstable ELR.

= bad weather, fierce clouds, flatline, fluffy cloud, big supercooled water droplets

Question 13

What is humidity:

Answer 13

amount of water vapour in the air.

Question 14

Saturation

Answer 14

The total maximum amount of water vapour that can be held in the air.

Question 15

What’s used to measure humidity?

Answer 15

Tephigram graph or radiosonde

Question 16

Inversions? Two types

And what do they generally mean?

Answer 16

Very stable conditions
Temperatures increase with height
Surface inversion(begins at surface)
Inversion aloft (begins higher in altitude)

Question 17

(Inversion formations)

Surface cooling

Answer 17

Ground is cooling. Conducts cool air above it. But there’s warm air higher above, from earlier sunny radiation. (If there’s no strong winds to distort this).

Question 18

Katabatic drainage

Answer 18

Cold air moving down into creek, falling below the warm air, (the warm air radiated of the ground of the creek).

Question 19

Frontal inversion

Answer 19

Warm air front coming into a envelope of cold air. Warm air can’t quite push the dense cold air, so ends up flowing on top of it.

Question 20

Subsidence inversion

Answer 20

Cold air that’s naturally descending compresses up against another cold layer above ground. As these layers are compressed, a higher pressure is formed, resulting in an increase of heat above the surface.
UP TO 6000ft

Question 21

Turbulence inversion

Answer 21

As wind rotates, almost barrel rolls, cold air from higher gets pulled down lower and warm air from below gets pushed upwards. UP TO 2000ft

Question 22

Marked Temperature inversions

Answer 22

Temp differences 10⚫️c or more
Between surface & 1000ft
warning symbol shown
Affects handling & safety
Marked wind shear at inversion

Question 23

How inversions are cleared:

Answer 23

Heating from below
Strong winds
Change of weather pattern

Question 24

Surface cooling graph shape?

What has wind got to be?

Answer 24

Graph goes to up to the right. Then goes up to the left.
(X axis temperature(to the right t increases))
(Y axis height (up is gain in height))

Question 24

Katabatic drainage shape of graph

Answer 24

Goes up to the left. Then straight line to the right. Then increases height again to the left. (Temperature on x axis, to the right = positive) (Height on y axis, up on the y axis= increase of height).

Question 25

Turbulence inversion graph shape

Answer 25

Up to the left. Straight line to the right. Up again the left.

Question 26

Altimeter measures?

Answer 26

Measures distance between a/c and sub scale setting