1- Atmosphere

Question 1

Atmosphere definition:

Answer 1

“the gaseous envelope surrounding a celestial body”

In the case of the earth, it is held together by gravity

Question 2

4 most common gases and percentages:

Answer 2

Nitrogen 78%, Oxygen 21%, Argon 0.95%, Carbon Dioxide 0.05%

Question 3

name the other gases found in the atmosphere in small amounts

Answer 3

(trace gases - as they come in a small quantity):

carbon monoxide, helium, methane, ozone, hydrogen

Question 4

What is a very important trace gas pilots need to know about:

Answer 4

water vapour

Despite its small quantity in atmosphere, it has the greatest effect on the weather. Without water vapour, we wouldn’t have weather.

Question 5

2 examples of Solid-state of water vapour:

Answer 5

hail and snow

Question 6

2 examples of Liquid state of water vapour:

Answer 6

clouds and rain

Question 7

Till how many km above the earth does the composition of gases stay relatively constant?

Then what happens?

Answer 7

1) 60km above earth

2) gravitational separation alters the composition of the atmosphere

Question 8

Layers in order of nearest to furthest from the Earth:

Answer 8

Troposphere - Stratosphere - Mesosphere

Question 9

what property is used to structure the atmosphere in various segments and layers?

Answer 9

Temperature

Question 10

Name the properties of the Troposphere

Answer 10

> as you go higher there is a drop in air temp

> because of gravity, this layer contains more than 70% of the total mass of the atmosphere

Question 11

What is the tropopause?

Answer 11

The tropopause is the upper boundary of the troposphere where the temp no longer drops with altitude increasing

Question 12

The thickness of the Troposphere and therefore the height of the Tropopause varies depending on where in the Earth you are.

Why is this?

Answer 12

The reason for this is the surface temperature: warmest/highest - coldest/lowest

Question 13

give the approximate height of the tropopause in the following:

Poles
Equator
Average (@45 degrees)

Answer 13

Poles - the height of tropopause about 8km

Equator - about 16km

Average - 11km/36,090ft @ 45 degrees latitude

Question 14

Where in the world is the Troposphere temp the lowest and highers and at what temp?

why?

Answer 14

1) Lowest at the Equator: about -80 degrees
Highest at the Poles: about -40 degrees

2)Why?
Knowing that the troposphere temperature decreases with height = the further away the tropopause is, the colder the air temp is

Question 15

The tropopause signifies the limit of most weather and significant cloud development.

Why is that?

Answer 15

The tropopause is where temp no longer drops with height which causes air to be stable (limits vertical movement of air). The lack of any vertical airflow prevents cloud and weather development

Question 16

Where is the stratosphere found?

Answer 16

50km above the earth

Question 17

Name 2 characteristics of the Stratosphere?

Answer 17

> characterised by the lack of any significant change of temp with height
stratosphere stops when temp begins to drop (to negative) with height again

Question 18

Remembering the graph shown in the video, there is an S shape in temp within this layer - why?

Answer 18

presence of ozone gas

Question 19

What does ISA stand for?

Answer 19

International Standard Atmosphere

Question 20

When was the ISA made and by who?

but whats a limitation of their model?

Answer 20

the ICAO in 1994

only went up to 32km above the earth

Question 21

State the ISA for temperature, density, and pressure at sea level

Answer 21

Temp: 15 degrees C
Pressure: 1013.25 hPa
Density: 1.225 kg/m^3

Question 22

What does MSL stand for?

Answer 22

Mean Sea Level

Question 23

Why is it so important to know how to find the ISA deviation?

Answer 23

It is used a lot in aviation and meteorology, especially when considering aircraft performance and error corrections for instruments.

Question 24

Example: there is an airfield 1000ft above sea level. the actual temp is 20 degrees, what is the ISA deviation?

Answer 24

A: knowing that at MSL the temperature is 15 degrees but also falls by 2 degrees every 1000ft up, we can say that the ISA is 13 degrees. The difference between the actual temp and ISA temp is 7 degrees.

The deviation is said in this form: it is 7 degrees warmer than ISA and this is shown by “ISA +7”

Question 25

example: Another day, at 10,000ft the real temp is -15 degrees, what is the ISA deviation?

Answer 25

A: Knowing 2 things: 1) that the ISA temp is 15 degrees. 2) that temp falls 2 degrees per 10,000ft. We do the following: 15 degrees - 20 degrees makes the ISA temp -5.

So the ISA Deviation is “ISA -10”