CLIMATE OF AFRICA

Factors Affecting the Climate of Africa

1. Latitude: Latitude refers to the location of a place on the earth’s surface in relation to the equator. Tropical latitudes where the sun’s altitude is always high have hotter temperature than lower latitudes where the sun’s altitude is generally low. These differences in temperature in relation to different latitudes affect climate.
2. Altitude: Altitude refers to the height of a place above the sea-level. As one moves higher into the atmosphere, the temperature decreases by 6.5˚C for every 1000m of ascent. This is called the normal lapse rate. High altitudes like high mountains contain less dust and water vapour and so allow heat to escape easily and remain cold.
3. Continentality or distance from the sea: Land surface heats up and cools more quickly than sea surfaces. As a result of this, the sea warms coastal regions in winter but cools them in summer. The warming and cooling effects of the sea are felt in areas closer to the coast than the hinterlands. Similarly, rain bearing winds drop more water in the coastal areas and less water as the wind moves into the hinterland.
4. Ocean currents: Ocean currents affect temperature. Warm ocean currents keep the surrounding lowlands warm. They lower summer temperature especially when carrying onshore winds. They force rain bearing wind to drop most water into the sea thereby, making the coastal land dry.
5. Planetary winds and pressure belts: Onshore winds tend to lower summer temperature and raise winter temperature in temperate latitudes. In tropical climates, winds have a cooling effect on day temperatures and a warming effect on night temperatures. Pressure belts also have direct effect on winds in the sense that wind blows from the area of high pressure to area of low pressure.
6. Slope and aspect: Steep slope experiences more rapid change in temperature than a gentle slope.
7. Cloud cover: Cloud reduces the amount of solar radiation reaching the earth’s surface and the amount of solar radiation escaping from the earth surface into space. Day temperature in the equatorial region is always high because of the heavy cloud cover.
8. Natural vegetation and soil: The thick foliage (leaves) of heavy forest cut off much of the incoming sunlight energy (insolation). As a result, the forest temperature is cooler and lower than that of the open ground (soil). Light soils reflect more heat than darker soils which are better absorbers of heat.

 

Types of Climate in Africa

The climatic types of Africa include:

1. The Equatorial Hot Climate: This is found in the Zaire Basin of Central Africa and in the Coast of West Africa (Except that of Ghana).

Characteristics of the Climate

• It has constant high temperature with daily temperature of 26˚C with no winter.
• It has high annual rainfall of over 200cm and rainfall is throughout the year.
• It has small annual temperature range of 2˚C – 3˚C.
• It has high humidity all year round with double maxima of rainfall.
• It has convectional rainfall accompanied by lightning and thunder.

 

2. The Tropical Continental (Sudan) Climate: This is found in West Africa, and then curves southwards in East Africa and Southern Africa.

Characteristics of the Climate

• The climate is characterized by hot, rainy and cool dry seasons.
• Extremes of temperature which varies from 21˚C – 32˚C.
• The annual temperature range is about 11˚C.
• High monthly temperature of about 27˚C.
• Annual rainfall is about 600 – 1500mm.
• Rainfall is seasonal mainly in summer.
• Rainfall is mainly convectional with single maximum.

 

3. The Mediterranean Climate: This is found in the horns or tips of Africa. In other words, it is found in south western part of South Africa (Cape Town) and the North West of Africa (Morocco, Algeria and Tunisia).

Characteristics of the Climate

• A dry warm summer of between 21˚C – 27˚C.
• Abundance of rainfall in winter with mean annual rainfall of 600-800m.
• Bright, sunny weather with hot, dry summer and wet mild winter.
• Prominence of local winds around the Mediterranean Sea such as Sirocco and Mistral.

 

4. The Hot Desert Climate: This climate is found in Sahara desert. It is caused by cold Canary current in North-West Africa and the Kalahari and Namib deserts caused by cold Benguella current in southern Africa.

Characteristics of the Climate

• High temperatures between 30˚C to 60˚C.
• Aridity or rainlessness is a common feature.
• Annual range of temperature varies from 9˚C to 20˚C.
• Annual rainfall is about 250mm.
• High rate of evaporation.
• Deserts are associated with cold currents.
• The relative humidity is very low.

 

5. The Warm Temperate Eastern Margin: This is only found in southern-eastern margin of Southern Africa (in Natal province).

Characteristics of the Climate

• It has a warm wet summer and a cool dry winter.
• Mean monthly temperature is between 4˚C and 26˚C.
• Annual temperature range is 25˚C.
• Annual rainfall is between 600 – 1500mm.

 

6. The Temperate Continental (Steppe): This is the temperate grasslands. Example is found in the veld of South Africa.

Characteristics of the Climate

• The vegetation is associated with the temperate continental climate, also called the steppe.
• Hot summer with temperature of over 20˚C.
• Cold winter with temperature below 0˚C.
• Average rainfall is about 508mm.
• Rainfall is convectional and light.

Characteristics of the Vegetation

• The dominant vegetation cover is savanna.
• The grasses have different names in different areas where they are found. These are: The Steppe of Central Europe and Russia, The Prairies of North America, The Pampas of Argentina, The Veld of South Africa, The Downs of Australia.

Economic Importance

• Mechanized agriculture is practiced where crops are grown with the aid of irrigation.
• Pastoral farming is also practiced due to abundance of grasses.
• The grassland is used as tourist centres.
• Nomadic herding is also carried out by the local people.

The savanna is also used for game reserves for wildlife for (wild animals).