Climate & Climate Classification – SS2 Geography Lesson Note (First Term)

Climate is the average weather condition of the atmosphere over a long period, usually about 30 to 35 years. It is affected by factors such as latitude, altitude and distance from the sea, and it is described using elements such as temperature, rainfall and wind. Climates are grouped into types and classified using the Greek and Koppen systems.

Behavioural objectives

By the end of the lesson, students should be able to:

• define climate;
• list the factors that affect climate and the elements of climate;
• state the location and examples of areas for the main types of climate;
• describe the Greek system of climate classification and its three zones;
• state the basis of Koppen’s classification of climate.

What factors affect climate?

1. Latitude
2. Altitude
3. Distance from the sea
4. Ocean currents
5. Cloud cover
6. Vegetation
7. Planetary wind

What are the elements of climate?

1. Temperature
2. Rainfall
3. Wind
4. Relative humidity
5. Pressure
6. Cloud cover
7. Sunshine

What are the types of climate?

Hot climates

Equatorial climate

Location: Within 5° North and South of the equator.

Areas: Amazon Basin of South America, Zaire Basin of Central Africa and the coast of West Africa.

Tropical continental (Sudan) climate

Location: Between 5° and 20° North and South of the equator.

Areas: Central America, north western part of South America, interior upland of Brazil and Bolivia, West Africa, part of East Africa, parts of India and South East Asia, and northern Australia.

Cold climates

Polar climate

Location: Around 90° North and South of the equator, especially around the poles.

Areas: Greenland, Iceland and Antarctica.

Tundra climate

Location: Around 60° to 90° North and South of the equator, especially around the Arctic and Antarctic circles.

Areas: Coastal strip of Greenland, northern Canada and Alaska, parts of Eurasia and Antarctica.

Desert climates

Hot desert climate

Location: Within latitudes 15° and 30° North and South of the equator.

Areas: Sahara desert, Arabian desert, Iranian desert, Thar desert, Namib desert, Kalahari desert, Great Australian desert and Atacama desert.

Cold desert climate

Location: Within 45° and 60° North and South of the equator.

Areas: Eurasia, North America and South America.

Other types of climate

Warm temperate climate, western margin (Mediterranean type)

Location: 30° to 45° North and South of the equator.

Areas: North Africa, south west of South Africa, central Chile, California, southern Australia, France, Spain and Italy.

Warm temperate climate, eastern margin (China type)

Location: 20° to 40° North and South of the equator.

Areas: China, the U.S.A, Mexico, Natal in South Africa and Australia.

Cool temperate climate, western margin (British type)

Location: 45° to 60° North and South of the equator.

Areas: Britain, France, Belgium, Netherlands, Denmark, Norway and British Columbia.

Cool temperate climate, eastern margin (Laurentian type)

Location: 40° and 50° North of the equator.

Areas: North eastern part of North America, north east Canada and northern Asia.

How is climate classified?

Climate varies from place to place. The two common classifications of climate are:

1. Greek system of classification
2. Koppen system of classification

Greek system of classification of climate

This is one of the earliest climatic classifications, made by the Greeks. The basis for the Greek classification is temperature. The system divides the world into three climatic zones:

1. Torrid zone: This zone is found within the tropics. It is very hot and has a high temperature throughout the year.
2. Temperate zone: It is found between the torrid and frigid zones and has a moderate temperature.
3. Frigid zone: It is found around the polar regions. It is very cold, with low temperatures all year round, and has ice-caps for most of the year.

Koppen system of classification of climate

The basis for Koppen’s classification of climate is temperature and rainfall. He identified five major climatic groups, which correspond with the five principal vegetation groups. These climatic groups are represented with capital letters as follows:

i. Tropical rainy climate

Environmental intervention

Environment is defined as the total surrounding or medium of any organism in a given area. This includes the physical surroundings, climatic factors and other living organisms in that surrounding.

Evaluation

1. Define climate.
2. List five factors that affect climate.
3. List the elements of climate.
4. State the basis of the Greek system of classification and name its three zones.
5. State the basis of Koppen’s classification of climate.

Assignment

1. State the location of the equatorial climate and name three areas where it is found.
2. Name the Mediterranean type of climate and list four areas where it is found.
3. Name five hot deserts of the world.