(a) Draw an outline map of Africa. On the map, mark and name the following: (i) the Tropical Climatic region; (ii) the Hot Desert Climatic region; (iii) the...

(a) Outline map of Africa showing the three climatic regions

The outline map below shows the position of each region asked for. The Tropical (savanna) Climatic region lies as two belts to the north and south of the equatorial zone; the Hot Desert Climatic region covers the Sahara in the north and the Kalahari/Namib in the south-west; and the Warm Temperate Eastern Margin Climatic region occupies the south-eastern coast of southern Africa (the Natal coast).

(b) Three characteristics of the Tropical Climate

1. Distinct wet and dry seasons. There is a single well-marked rainy season, with a peak about July, when the moist tropical maritime (South-West) winds blow, and a long dry season when the dry, dusty tropical continental (North-East trade / harmattan) winds blow.
2. High temperatures all year with a large annual range. Mean monthly temperatures stay high, between about \(21^\circ\mathrm{C}\) and \(32^\circ\mathrm{C}\), the hottest period coming just before the rains; the annual range of temperature is larger than in the equatorial zone.
3. Moderate, mainly convectional rainfall that decreases away from the Equator. Total annual rainfall averages about \(75\ \mathrm{cm}\) (\(750\ \mathrm{mm}\)), ranging from roughly \(60\ \mathrm{cm}\) to \(150\ \mathrm{cm}\); it falls chiefly as heavy convectional showers in the summer months and decreases from the equatorial borders towards the desert margins. Relative humidity is high (about 60-80%) in the wet season but low (about 20-40%) in the dry season.

(c) Three ways the vegetation (savanna) has adapted to the climate

1. Trees are deciduous and shed their leaves in the dry season to cut down water loss through transpiration; the vegetation is therefore seasonal, green in the rains and brown in the dry season.
2. Plants store water and reach deep water. Some trees, such as the baobab, develop swollen, bulbous trunks that store water, while many have long tap roots that reach down to underground water during the dry season.
3. Protective leaves, bark and root systems. Trees have thick, fire-resistant bark and narrow, thorny or waxy leaves that reduce transpiration, while the tall coarse grasses survive the dry season and annual bush burning as resistant underground roots and seeds, sprouting again with the first rains.