THE ATMOSPHERE

Question 1

What’s the atmosphere composed of?

Answer 1

78% Nitrogen
21% Oxygen
1% Argon
0,03% CO2

Question 2

How high is the troposphere

• At the equator
• 45 deg lat
• At the poles

Answer 2

52’000ft at the equator (-80 deg)
36’090ft at 45 deg lag (-56 deg)
26’000ft at the poles (-50 deg)

Question 3

How does the troposphere change in height with temp changes?

Answer 3

The colder the temp the lower the troposphere

Question 4

What layer is above the troposphere?

How far up does it extend and what happens to temperature in this layer and also why does it increase slightly ?

Answer 4

Stratosphere that extends from 36’096ft - 170’000ft
Temp remains constant at start, then increases to 0 deg at the top.
Ozone causes surrounding air to warm

Question 5

Define ISA?

Answer 5

At MSL:
\+15 deg with a decrease of 1,98 deg/1'000ft up to 36'096ft
1013.25 hPa
1225 g/m2 (dry air density
 760 g/m2 (water vapor)

Question 6

What is JSA?

Answer 6

Jet standard atmosphere
Used by engine manufacturers
+15 deg @ MSL and decreasing by 2 degrees/1’000ft to infinity

Question 7

Define “Specific Heat”

Answer 7

Water has high specific heat
Low specific heat loses and gains heat more quickly
The amount of heat needed to raise the temperature by 1 degree

Question 8

How is the earth surface heated?

Answer 8

Suns short wave radiation heats the surface of the earth but not the atmosphere. Long wave radiation from the earth heats the atmosphere from below.

Question 9

Boiling point and freezing point in Fahrenheit?

Answer 9

Boiling point = 212 deg F

Freezing point = 32 deg F

Question 10

Boiling point and freezing point in Kelvin?

Answer 10

Boiling point = 373 K

Freezing point = 273 K

Question 11

What is used to measure surface temp?

Answer 11

A Stevenson screen at a height at 4ft

Question 12

When is insolation highest and when is temp highest?

Answer 12

Insolation highest at 12:00 and temp highest at 15:00

Question 13

What is the Greenhouse effect?

Answer 13

Atmosphere (water vapour and CO2) is transparent to solar short wave radiation but don’t allow long wave terrestial radiation to leave and go back into space. This leads to an increase in temp on the ground

Question 14

Where are the “3 breaks” in the troposphere?

Answer 14

1 st: 40 deg lat

2nd: 55 deg lat
3rd: 60-70 deg lat

Occurs where large temp diff occurs.
Co-incides with the Hadley- and Farrel cells
These breaks/temp diff causes strong winds called jetstreams

Question 15

What’s an Isobar?

Answer 15

Places of equal pressure

Question 16

How does pressure change with height?

Answer 16

Pressure decreases as height increases and at a decreasing rate

Question 17

How does the pressure change with height depending of weather it’s warm or cold?

Answer 17

Pressure decreases more rapidly in cold air compared to warm air

Question 18

How much change in height is 1 hPa at MSL?

Answer 18

27 ft

Question 19

How does wind blow around a Low/High pressure system in the Northern hemisphere?

Answer 19

Anti-clockwise around a Low

Clockwise around a High

Question 20

What are the properties of a Low pressure system?

Answer 20

Convergence at the surface and divergence at altitude

Question 21

What happens to density with height?

What’s the contradiction here?

Answer 21

Density decreases with height
Pressure decreases with height which decreases density but temp decreases with height that would increase density.
Pressure have the overriding effect
Increased humidity also decreases density

Question 22

Why is there relatively higher density at height over the equator compared to over the poles?

Answer 22

Density decreases relatively quickly in cold air compared to in warm air.

Question 23

How does density altitude change with deviation from ISA?

Answer 23

By 118,8 deg C per degress away from ISA

Question 24

How is humidity measured?

Answer 24

By a dry/wet bulb hygrometer
A cloth of destilled water is wrapped around a bulb. Water in the cloth evaporates into the air. Latent heat is absorbed from the atomsphere which lowers the temp scale until saturation occurs. Dew point is then given

Question 25

How can air become saturated?

Answer 25

By adding extra water vapour or by lowering the temperature

Question 26

Describe the relationship between
Solid - Liquid - Gas
and they change from one an other

Answer 26

Solid - Liquid is melting, latent heat absorbed
Liquid - Gas is evaporation, latent heat absorbed

Gas - Liquid is condensation, latent heat released
Liquid - Solid is freezing, latent heat released

Gas - Solid directly is called sublimation

Question 27

Can you convert 12 degrees C to F?

Answer 27

Ballpark - Degrees Celsius multiply by 2 and add 32 (Vice/Versa for F to C). EX: 12x2=24+32=56