The Atmosphere

Question 1

The composition of the atmosphere by percentage is:

Answer 1

78% Nitrogen

20. 95% Oxygen
21. 93% Argon

Question 2

This forms a layer in the stratosphere which acts as a shield against the harmful ultra violet rays of the sun:

Answer 2

Ozone

Question 3

The 4 layers of the atmosphere in order is:

Answer 3

The Troposphere

The Stratosphere

The Mesosphere

The Ionosphere

Question 4

The troposphere:

Extends to(polar, tropical and 45 degree latitudes):

The lapse rate?

The pressure decrease rate?

Answer 4

8 km above cold polar areas and;

16 km above warm tropical regions

At the 45 degree latitudes the average height is 11km

1.98 celsius per 1 000ft up to a height of 11km(tropopause average), thereafter the temperature remains constant at -56.5 celsius.

Pressure decreases at an average rate of 1 hPa per 27 feet. This pressure decrease is not constant and reduces with altitude, approximately 1 hPa per 47 feet at 20 000ft.

Question 5

The stratosphere:

Extends to -

The lapse rate?

Answer 5

From the earth’s surface to 50km.

The temperature remains constant at -56.5 celsius up to 20km. From 20km to 32km the temperature increases by 0.3 celsius / 1 000ft up to a peak of 0 at 50km. The temperature starts to increase due to the ozone layer which absorbs intense solar radiation.

Question 6

The mesosphere extends to:

Answer 6

From the earth’s surface 80km

Question 7

The Ionosphere extends to:

Answer 7

1 000km.

Question 8

Which of the 4 atmosphere layers will one experience intense solar radiation from the sun’s ultra violet rays and ions that will reflect, refract or attenuate radio waves?

Answer 8

The ionosphere

Question 9

Water vapour only weighs -

Answer 9

5/8ths that of dry air

Question 10

Ozone layer:

It’s purpose -

Where it can be found -

Answer 10

Acts as a shield against harmful ultra violet rays

In the stratosphere

Question 11

Explain condensation nuclei:

Answer 11

Water vapour requires a nucleus to cling to in order to create water droplets. This is provided by microscopic impurities such as dust salt from the sea, ash and soot from volcanoes, as moke and nitrous acid.

Question 12

The 4 atmosphere layers are(in order):

Answer 12

1. The troposphere
2. The stratosphere
3. The mesosphere
4. The Ionosphere

Question 13

Why will weather occur more commonly in the troposphere and rarely in the stratosphere?

Answer 13

Because of a higher concentration of water vapour and condensation nuclei.

Question 14

In the structure of weather formation there are three major elements present, these are -

Answer 14

1. Temperature
2. Pressure
3. Humidity

Question 15

As altitude increases, the air becomes less dense. Therefore the change in feet per hPa will increase.
You only need to know the values below for the exam:

1hPa = \_\_ft at sl
1hPa = \_\_ft at 10,000ft
1hPa = \_\_ft at 18000ft

Answer 15

As altitude increases, the air becomes less dense. Therefore the change in feet per hPa will increase.
You only need to know the values below for the exam:
1hPa = 27ft at sl
1hPa = 36ft at 10,000ft
1hPa = 50ft at 18000ft

Question 16

Poles: Height 8km; Temp -

Mid-latitudes: Height 11km; Temp -

Equator: 16km; Temp -

Answer 16

Poles: Height 8km; Temp -50 °C

Mid-latitudes: Height 11km; Temp -56 °C

Equator: 16km; Temp -75 °C