Weather

Question 1

Define Weather.

Answer 1

Weather is the state of the atmosphere at a given time and place.

Question 2

State the three parts of the atmosphere, in order of height {highest layer to lowest layer}.

Answer 2

The Ionosphere.
The Stratosphere.
The Troposphere.

Question 3

Define the Normal Lapse Rate.

Answer 3

This is the decrease of temperature with altitude, in the troposphere, at a rate of 6.5°C per 1000m of ascent.

– The troposphere contains 90% of the atmosphere‘s water vapour.
– The behaviour of air in the troposphere gives rise to our weather.

Question 4

What isothermal layer separates:
a} The Troposphere from the Stratosphere
b} The stratosphere from the ionosphere

Answer 4

a} The Tropopause.
b} The Stratopause.

Question 5

What is causing damage to the ozone layer?

[1]

Answer 5

Chlorofluoro Carbons.

– The O–zone layer is found at 20–30 km above the earth.

– CFCs are being released into the atmosphere 5 times faster that they can be absorbed.
– They react with the O–zone layer and dissolve it.

Question 6

Give 3 examples of producers Chlorofluoro Carbons.

Answer 6

i. Foam packaging manufacture
ii. Refrigerator coolants
iii. Aerosols in deodorants

Question 7

List at least 4 effects of Ultra Violet Radiation.

Answer 7

1. Increased eye damage – it causes cataracts.
2. Increased snow blindness
3. More skin cancer and sun burn – especially for fairer skinned people
4. Slows down photosynthesis and germination
5. Damage to oxygen producing plankton
6. Accelerated aging
7. Genetic mutations

Question 8

State the 8 elements of weather.

Answer 8

1. Temperature
2. Rainfall
3. Humidity
4. Sunshine
5. Wind speed
6. Wind direction
7. Pressure
8. Cloud cover

Question 9

List the 4 things to be considered when siting a weather station.

Answer 9

1. It should be on flat ground so that instruments are upright.
2. It must be on short grass, which is a poor conductor of heat.
3. It must be in an open space so that instruments measure accurately.
   – No trees to avoid shade.
   – No building to avoid intercepted rainfall and wind blockage.
4. It must be fenced and gated to prevent vandalism.

Question 10

What are the 3 instruments kept in a Stevenson‘s screen?

Answer 10

1. A Six‘s Thermometer,
2. a Hygrometer and
3. a Barometer

– These are kept in the Stevenson‘s Screen, a wooden box, so that they measure more accurately.

Question 11

What 5 features are on a Stevenson‘s Screen to ensure that the instruments inside it measure accurately?

Answer 11

1. Louvred to allow free circulation of air.
2. Painted white to reflect heat from the sun.
3. South facing door to prevent direct heat from entering.
4. Legs that are 1.2m above the ground to prevent instruments from measuring ground heat.
5. Double board on the roof to insulate the instruments.

Question 12

Formula for:

Diurnal Range of the Temperature =

Answer 12

Maximum temperature – Minimum temperature

Question 13

Formula for:
Mean Daily Temperature =

Answer 13

Maximum temperature + Minimum temperature
_____________________________
2

Question 14

What is “the depression of the wet bulb thermometer?“

Answer 14

This is the difference between the two thermometer readings on a Hygrometer.

Question 15

On a Hygrometer, explain the following:
No difference between the two thermometers –

Answer 15

No difference between the two thermometers –*
Air is saturated/Dew point has been reached*

– The final reading is given as a percentage, eg 100%, which is when the atmosphere is saturated and it can rain anytime.
– A relative humidity below 50% shows very low humidity.

Question 16

Does the arrow of a wind vane point to where it is coming from or where it is going.

Answer 16

The arrow of a wind vane points to where the wind is coming from.

Question 17

State 4 precautions when using and taking measurements from a rain gauge.

Answer 17

1. Make sure that the collecting can is completely empty before resetting.
2. The top of the funnel should be 30cm above ground to prevent splashes from entering.
3. The measuring cylinder should be level when rainfall amounts are being read.
4. Make sure the bottom part of the outer can is sunk into a rock pedestal to prevent vandalism and to prevent evaporation of collected water.

Question 18

State the 3 high level clouds.

Answer 18

1. Cirrus clouds
2. Cirrocumulus clouds
3. Cirrostratus clouds

Question 19

State the 2 mid level clouds.

Answer 19

1. Altocumulus
2. Altostratus

Question 20

State the 5 low level clouds.

Answer 20

1. Stratocumulus
2. Cumulus
3. Cumulonimbus
4. Stratus
5. Nimbostratus

Question 21

State the identification features of Cirrus clouds and what they are made of.

Answer 21

Cirrus clouds are made of ice crystals.

Identification features:
i. High level
ii. Wispy
iii. Feather–like
iv. Look like tufts of hair

Question 22

State the identification features of Cirrocumulus clouds and what they are made of.

Answer 22

Cirrocumulus clouds are made almost entirely of ice crystals.

identification features:
1. High level
2. Small white clouds usually grouped together
3. Little cloudlets are regularly spaced often appearing as ripples in the sky or like scaly fish skin

Question 23

State the identification features of Cirrostratus clouds and what they are made of.

Answer 23

Made up of ice crystals.

Identification Features:
1. High clouds in layers
2. Transparent, covering large areas of sky. Sometimes produce white/coloured rings, spots or arcs around the sun or moon.
3. Can span thousands of miles, be smooth and fibrous and are often fringed with cirrus clouds.

Question 24

State the identification features of Altocumulus clouds and what they are made of.

Answer 24

Made up of a mix of ice and water.

Identification features:
1. Small, midlevel clouds
2. Usually exist as rounded clumps

Question 25

Describe what altostratus clouds are made of and what they look like.

Answer 25

These are made of a mixture of water droplets and ice crystals.

Appearance:
1. They are thin, enough for anyone to weakly see the sun through them.
2. Often spread over a large area and are typically featureless.

Question 26

Describe what Stratocumulus clouds are made of and what they look like.

Answer 26

Made of water droplets, and sometimes ice crystals as well.

Appearance:
1. Low level clumps or patches
2. Vary in colour from bright white to dark grey
3. Well defined bases, most common clouds.
4. Can join together but usually have gaps in between them.

Question 27

Describe the make up and appearance of Cumulus clouds.

Answer 27

Made up of water droplets and sometimes ice crystals depending on the type of cumulus cloud.

Appearance:
1. Heaped, with flat bases and globular upper surfaces.
2. Detached, individual and cauliflower shaped.
3. Brilliant white tops with bases that are usually dark.

Question 28

Describe the make up and appearance of Cumulonimbus clouds.

Answer 28

Made up of water droplets, and ice crystals, especially in its upper portion.

Appearance:
1. Extend high into the sky like towers or plumes.
2. Icy anvil shaped top.
3. Flat base, may only lie few hundred feet above the surface.

Question 29

Describe the make up and appearance of Stratus clouds.

Answer 29

Made up of ice/ice crystals.

Appearance:
1. Lowest lying cloud type, sometimes appearing at the surface in mist or cloud form.
2. Tend to be featureless – cover the sky in a blanket of white or grey.

Question 30

Describe the make up and appearance of Nimbostratus clouds.

Answer 30

Made up of water droplets.

Appearance:
1. Dark, grey, featureless layers of cloud, thick enough to block out the sun.
2. Produce persistent rain.

Question 31

On a Hygrometer, explain the following:
Small difference between the two thermometers –

Answer 31

Small difference between the two thermometers –*
Humidity is high [atmosphere is wet]*

– The final reading is given as a percentage, eg 100%, which is when the atmosphere is saturated and it can rain anytime.
– A relative humidity below 50% shows very low humidity.

Question 32

On a Hygrometer, explain the following:
Large difference between the two thermometers –

Answer 32

Large difference between the two thermometers –
**Humidity is low [atmosphere is dry]
**

– The final reading is given as a percentage, eg 100%, which is when the atmosphere is saturated and it can rain anytime.
– A relative humidity below 50% shows very low humidity.

Question 33

What is Humidity?

Answer 33

Humidity is the amount of water vapour in the atmosphere.

Question 34

Describe how a hygrometer functions to measure humidity.

[3]

Answer 34

1. It consists of 2 thermometers
2. One thermometer has its bulb covered in a muslin cloth dipped in water, while the other is bare
3. When humidity is low, the atmosphere is dry and water evaporates from the muslin cloth, cooling the bulb of the wet-bukb thermometer making the two temperature readings different.