Atmospheric Stability

Question 1

What 3 states can moisture exist?

Answer 1

• Liquid
• Solid
• Gas

Question 2

What is the process of;

Gas to Solid?

Answer 2

Deposition

Question 3

What is the process of;

Solid to Gas?

Answer 3

Sublimation

Question 4

What is the process of;

Gas to Liquid?

Answer 4

Condensation

Question 5

What is the process of;

Liquid to Gas?

Answer 5

Evaporation

Question 6

What is the process of;

Solid to Liquid?

Answer 6

Melting

Question 7

What is the process of;

Liquid to Solid?

Answer 7

Freezing

Question 8

How is a change of state achieved?

Answer 8

Exchange of latent heat

Question 9

What does humidity refer to?

Answer 9

Amount of water vapour contained in air sample

Question 10

How is humidity measured?

Answer 10

Psychrometer

Question 11

What is relative humidity expressed as?

Answer 11

Percentage

Question 12

When is a sample of air said to be saturated?

Answer 12

When the air sample can hold no more water without condensation occurring

Question 13

Relative humidity %=

Answer 13

Actual Mass of water x 100/ Mass of water vapour at saturation

Question 14

What influences the amount of water being able to be held?

Answer 14

• Temperature

- Pressure

Question 15

Increased temperature increases the stability of an air sample and is there for able to hold more or less water?

Answer 15

More

Question 16

The relative humidity is decreased with….

Answer 16

An increase in temperature

Question 17

What is dew point?

Answer 17

Temperature at which a sample of air must be cooled to reach saturation

Question 18

As a parcel of air rises up through the atmosphere what happens to the surrounding air pressure?

Answer 18

Reduces

Question 19

A parcel of air cools when it rises why is this?

Answer 19

The volume of parcels increases and the temperature reduces. Process called expansion

Question 20

When an air sample changes temperature due to pressure or volume this is called?

Answer 20

Adiabatic

Question 21

What is the lapse rate?

Answer 21

Lapse rate is the rate at which an air sample cools as it rises

Question 22

What does the lapse rate depend on?

Answer 22

Whether the sample of air is dry or saturated

Question 23

What is the lapse rate of unsaturated air?

Answer 23

3/1000ft

DALR

Question 24

What is the lapse rate of saturated air?

Answer 24

1.5/1000ft

SALR

Question 25

What causes saturated air to move more slowly?

Answer 25

As water vapour condenses to liquid, latent heat is released causing it to cool more slowly

Question 26

What is the Dew point lapse rate?

Answer 26

.6/1000ft

Question 27

What is considered a stable atmosphere?

Answer 27

One which an air parcel return to its original level after being forced vertically

Question 28

What is the air said to be if it continues to rise on its own after being forced vertically?

Answer 28

Unstable

Question 29

Stability or instability depends on?

Answer 29

Relative lapse rates and the air parcels being forced vertically

Question 30

What is ELR?

Answer 30

Environmental Lapse Rate

Question 31

When does stability exist?

Answer 31

When the ELR is less than the SALR

Question 32

When does instability exist?

Answer 32

When ELR is greater than DALR

Question 33

When does conditional stability exist?

Answer 33

ELR is less than DALR but greater than SALR

Question 34

What does conditional stability mean?

Answer 34

The parcel remains dry and cools at the DALR, conditions will be stable. If dew point is reached the parcel will cool at the slower SALR and if sufficient lifting occurs become warmer than the environment resulting in instability

Question 35

How do you find out the cloud base height?

Answer 35

Subtract the surface dew point from the actual surface temperature and divide by 2.4

Question 36

When does an inversion exist?

Answer 36

Whenever a layer of warm air exists above cooler air

Question 37

What is a surface inversion?

Answer 37

Air close to the surface is cooled at night by conduction

Question 38

When is surface inversion most common?

Answer 38

Just before dawn when the surface temperature is lowest

Question 39

What is a turbulence inversion?

Answer 39

Moderate winds at low level may cause adiabatic expansion and cooling in lower layers due to mixing

Question 40

What is a frontal inversion?

Answer 40

Boundary between two air masses of different temperatures may form an inversion as the warm air slides up over the cooler air

Question 41

What is a subsidence inversion?

Answer 41

As a column of air subsides the top of the column undergoes greater compression and heating than the bottom

Question 42

Are inversions associated with stable or unstable conditions?

Answer 42

Stable

Question 43

Are there bumpy or smooth conditions above or below the inversion layer?

Answer 43

Above- Smooth | Below- Bumpy

Question 44

What is a fohn wind?

Answer 44

Hot, dry breeze blowing down lee side of a mountain

Question 45

How is a fohn wind created?

Answer 45

Cloud base on lee slope is higher than on the windward slope due to precipitation on the Winward slope and a change in dew point

Question 46

On the lee slope surface temperatures are higher because...

Answer 46

The air warms at the DALR from the higher cloud base through a greater depth than it cooled on the windward side