Weather and Climate

Question 1

What is Climate?

Answer 1

Climate refers to the average atmospheric conditions over a wide area over a long period of time of at least 30 years.

Question 2

What is Weather?

Answer 2

Weather refers to the state of the atmosphere at a place over a short period of time.

Question 3

What is humidity?

Answer 3

1. The amount of water vapor in the air

Question 4

What is absolute humidity?

Answer 4

The actual amount of water vapour in the air at that temperature (percentage)

Question 5

What is relative humidity, and how is it calculated?

Answer 5

1. The relationship between the actual amount of water vapor in the air and the maximum amount of water vapor air can hold (ratio)
2. Absolute humidity/maximum amount of water vapor air can hold at that particular temperature

Question 6

What is the dew point?

Answer 6

1. The temperature at which water vapor condenses to liquid water
2. The temperature where saturation of air occurs

Question 7

What is the saturation point?

Answer 7

The state where air reaches 100% relative humidity

Question 8

How is relative humidity affected by the temperature?

Answer 8

Colder
- the maximum amount the air can hold decreases
- relative humidity increases

Hotter
- the maximum amount the air can hold increases
- relative humidity drops

Question 9

What are the two types of rainfall?

Answer 9

1. Convectional rain
2. Relief rain

Question 10

How is convectional rain formed?

Answer 10

1. The Sun heats the earth’s surface, and the warm surface heats the air above it by conduction.
2. The warm air is less dense and unstable, causing it to rise.
3. As it rises, it expands and cools to dew point temperature. Water vapor condenses on condensation nuclei to form water droplets in the form of clouds.
4. As water droplets coalesce (or merge), they become larger.
5. Over time, huge towering cumulonimbus clouds develop.
   When water droplets are too large and heavy to be suspended, convectional rain falls.

Question 11

How is relief rain formed?

Answer 11

1. Air passes over the sea and picks up moisture. Warm, moist air arrives at the coast.
2. Air rises the windward side of the hill/mountain.
3. As air rises, it cools to dew point temperature and air becomes saturated.
4. Condensation begins to occur and clouds are formed.
5. When water droplets become large and heavy enough, relief rain falls on the windward side.
6. After crossing the mountain, the dry descending air becomes warmer and drier.