3.1 Climate and vegetation regions of the world

Water has a larger heat retention capacity than the land has. The water, however, takes longer to heat during the day. Therefore the land reaches higher day temperatures than the water. The sea then has a “cool” influence from the sea to the land. During the night the land cools down much faster than the water, which then causes a “warm” influence from the sea to the land.

The result is that places along the coast or large water masses, experience a moderate temperature. The margin between maximum and minimum is not very big.

Hot water evaporates faster and better than cold water. There is more evaporation above a warm sea current. This results in a higher precipitation in areas that border on warm sea currents.

Relief

In grade 5 we learnt that the escarpment diverts the rain bearing winds and clouds away from the interior. Mountains also have a sunny side and a shady side. The sunny sides have higher average temperatures, and the shady sides have lower average temperatures.

2. Climate and vegetation

• As climate exerts an effect on vegetation, we find that both vegetation and human activities are relatively similar over large areas. Where one region changes into another, we find that a gradual change occurs over a large area. Such an area is referred to as a transitional/intermediate zone . Forests do not suddenly change to grasslands, but the occurrence of trees gradually decreases and grasslands increase. The map on page 16 shows the different rainfall and vegetation regions of the world. Remember, there are no specific boundaries. Maps will therefore differ slightly from one another.
• The interaction between plants, animals, soil and climate within a demarcated area develops an ecological system, which we simply call an ecosystem. (Ecosystem = a selection of plants and animals in their own environment.)
• The largest ecosystems that have developed on the earth are known as biomes . (Biome = a large area that houses similar plants and animals and relates to the distribution of climatic regions).

Activity 2:

To study climatic information

[lo 1.2, 1.3, 1.5]

Study the climatic information in the table on page 15 and answer the following questions:

• Determine the longitudinal and latitudinal position of each of these two cities. Which city is closest to the Equator?
• In which countries are the cities situated?
• Select a suitable scale and represent the climatological information graphically. Use a line graph to illustrate the temperature and a bar graph to illustrate the rainfall.
• Which city experiences the greatest temperature fluctuations? How does this compare with where you live?
• Explain why the temperatures are so high and the temperature variations so little for these two cities.
• During which months do these cities experience the highest temperatures and have the highest rainfall? How does this compare with where you live?

Table 1: Climatic information for Belèm and Singapore

Assessment:

Memorandum

Activity 1:

• Thabana Ntlenjana – 3 482 m

• S 27.20 E

Activity 2:

• Belèm : 1.27 S 48.29 W
• Singapore : 1.17 N 103.51 E

• Belèm : Brasil
• Singapore : Malaysia

• Belèm

• Intense isolation of the sun throughout the year. Every day is approximately 12 hours long. Angle of incidence of the rays of the sun is vertical or close to it throughout the year.

• Belèm : Temperature – November : Rain – February
• Singapore : Temperature – April : Rain – December