Stability of the Atmosphere

Question 1

What 3 factors affect the stability of the atmosphere?

Answer 1

1. The temperature lapse rate of the air compared to the surrounding atmosphere
2. The water content of the air
3. The presence of ‘lifting mechanisms’

Question 2

What is an adiabatic process?

Answer 2

When an air parcel expands and cools, or compresses and warms, with no interchange of heat with its outside surroundings.

Question 3

What is the Level of Condensation?

Answer 3

The point at which a parcel of air becomes saturated.

Question 4

What type of air does the DALR apply to? What is its value?

Answer 4

• Dry air or moist air that isn’t saturated

- 3 C/1000 ft

Question 5

What is the dew point?

Answer 5

• The temperature that air muse be cooled in order for dry air to become saturated.
• Cooling beyond this will result in visible moisture forming.

Question 6

What type of air does the SALR apply to? What is its value? Why is it less than DALR?

Answer 6

• 1.5 C/1000 ft
• Apply to saturated air
• Less than DALR because of release of latent heat when condensation is formed.

Question 7

What is the standard ISA ELR?

Answer 7

2 C/1000 ft

Question 8

What can be said about stability of atmosphere when ELR > DALR?

Answer 8

Absolutely unstable

Question 9

What can be said about stability of atmosphere when DALR < ELR < SALR?

Answer 9

Conditionally stable

Question 10

What can be said about stability of atmosphere when ELR < SALR?

Answer 10

Absolutely stable

Question 11

What is a skewT-LogP diagram?

Answer 11

Aerological diagram that shows the vertical distribution of temperature and moisture in the atmosphere.