1. Introduction

Question 1

Air pressure

Answer 1

Decreases w/ height

Fewer air molecules with increased altitude

Air density decreases w/ height

Question 2

Cold and warm Air temperature

Answer 2

Cold air molecules move slower and takes up less space; air has a higher density

Warm/hot air molecules more faster and takes up more space; air will have less density

Question 3

High water vapour

Answer 3

Low air density and pressure

Question 4

Low water vapour

Answer 4

High air density and pressure

Question 5

Does air density increase or decrease with height?

Answer 5

Decreases

Question 6

What is the boundary layer?

Answer 6

Lowest part of atmosphere, surface to 3000’

Question 7

What are the characteristics of the boundary layer

Answer 7

1. Wind increases with height
2. Vertical currents occur as a result of friction of wind with earth’s surface
3. Tends to be turbulent because of eddies in the wind flow caused by overturning of air
4. Deeper in the summer, shallower in winter
5. Deeper during the day, shallower at night
6. Subject to cloud formation

Question 8

What is the relationship between air temp and air moisture?

Answer 8

The higher the temp, the more moisture it can hold

Question 9

What is evaporation?

Answer 9

Liquid to gas

Question 10

Sublimation

Answer 10

Solid to gas

Question 11

Condensation

Answer 11

Gas to liquid

Question 12

Melting

Answer 12

Solid to liquid

Question 13

Deposition

Answer 13

Gas to solid

Question 14

Freezing

Answer 14

Liquid to solid

Question 15

Dew point temp (Td)

Answer 15

Temp to which air must be cooled in order for condensation to occur

Always lower or equal to air temp

Question 16

Air saturation

Answer 16

Max amount of water vapour air can hold

Question 17

Relative humidity

Answer 17

Amount of water vapour that is in the air relative to the amount of water vapour the air can hold at that temp

Question 18

Conduction

Answer 18

Heat transfer through physical contact, slow process

Question 19

Convection

Answer 19

Heat transfer by the motion of fluids, faster than conduction

Question 20

Radiation

Answer 20

Heat transfer by electromagnetic waves, fastest

Question 21

Advection

Answer 21

Heat transfer by horizontal flow of a fluid in the atmosphere or sphere

Question 22

Radiation warming

Answer 22

Heat from the sun, ground warms faster than water

Question 23

Advection warming

Answer 23

Cold air moving over a warmer surface heated by conduction

Question 24

Compression warming

Answer 24

Air descending down the side of a hill hill encounter higher pressure and compresses and warms

Question 25

Atmospheric cooling reasons

Answer 25

1. The increase in density of the air

2. When moist air cools it creates clouds, fog and precipitation in the lower levels

Question 26

Radiation cooling

Answer 26

Earth giving off heat without the Sun to reheat

Question 27

Advection cooling

Answer 27

Warm air moves over cold surface

Question 28

Expansion cooling

Answer 28

Air rises it reaches areas of lower pressure, it expands and cools

Question 29

Atmospheric vertical stability

Answer 29

Directly related to the changes of temp with height

Question 30

Characteristics of unstable air

Answer 30

1 cumuliform clouds

2. Showery precipitation
3. Turbulence
4. Good Wis except in blowing obstruction

Question 31

Characteristics of stable air

Answer 31

1. stratiform clouds and fog
2. Continuous precipitation
3. Smooth air
4. Fair to poor vis in lat and smoke

Question 32

What does a stable atmosphere mean?

Answer 32

There is no vertical overturning

Question 33

What are some of the characteristics of an unstable atmosphere to aircrew?

Answer 33

Turbulence, gusty winds, good vis, convective clouds, thunderstorms

Question 34

What are some of the characteristics of a stable atmosphere?

Answer 34

Smooth flying, layered clouds, continuous precipitation

Question 35

When is air most stable over the North Atlantic

Answer 35

Spring and summer

Question 36

How does icing affect an aircraft

Answer 36

Decreases lift on take off, reduce power, restricts the performance