The Geographic Analysis of Africa

Africa in a Geographic Analysis
POSITION AND SIZE
Africa is believed to be the second largest continent on earth. Africa’s area is approximated to be about 11.5 millions square miles. It stretches for around 35o on each side of the equator and it is crossed by both Tropics. This makes the bulk of the continent to be in the tropical latitudes. Base on the shape of Africa, the north of the equator is bigger than that to the south.

PHYSICAL FEATURES
The continent has Atlas Mountains in the north-west which form part of the old-world fold mountain system. There is also the existence of a huge plateau rising by steep escarpments from narrow coastal plains. A line of the plateau slightly convex towards the south-east, extending from the mouth of the Congo to Port Sudan on the Red Sea, divides the plateau into two regions differing in elevation. The north-west of the plateau portion of the plateau is comparatively low plateau consisting mainly of the Sahara Desert crossing from south-east to north-west by the Ahaggar Plateau and the Tibesti Highland. The south-east consists of a much loftier plateau bordered on its seawards side by mountains that are often higher than the interior. This is divided into phases namely: the Abyssinian Plateau of volcanic origin; the Central Lake Plateau in the middle of which lies Lake Victoria; and the South African Plateau whose eastern edge is formed by Drakensburgs.
The Eastern Rift Valley of Africa is part of that running from Palestine through the Gulf of Akaba and the Red Sea, across Abyssinian, past Lake Rudolf, to Lake Nyasa. From the northern end of the latter Lake, a branch rift valley runs north-west through Lake Tanganyika and Edward to Lake Albert. On the east side of the Eastern Rift Valley the extinct volcanoes of Kenya, on the Equator, and Kilimanjaro, some 200 miles to the south, rise to 17,040 and 19,320 feet respectively. Between Lake Albert and Lake Edward the Ruwenzori Range rises to the east of the western rift valley, while south of the latter lake are the Mfumbiro Mountains with the still active volcano of kirunga.

DRAINAGE
River Nile is the longest river in Africa. It emerged from Lake Victoria and flows about 4000 miles towards the Mediterranean. Below Berber it transverses a desert region and receives no tributaries. The River Congo covers about 3000 miles and drains an area of about 1 500 000 square miles. Most of its basin lies in the equatorial wet belt with the volume much greater than the Nile in certain season.
The River Niger covers about 2300 miles. The rivers Niger, Senegal and Gambia rise in the Futa Jallon Highlands. The River Zambezi whose source is not far from the headway of the Congo River covers about 1800 miles before it enters into the India Ocean. In the Southern Africa, River Limpopo’s flowing route ends in the Indian Ocean while River Orange enters into the Atlantic Ocean.
Analytically, about one-third of Africa is an inland Drainage Region. Lake Chad into which flows the intermittent Shari, is an area of inland drainage lying south-east of the Sahara. Lake Ngami of similar region in South-West Africa; Lake Rudolf also has no outlet to the Ocean.
Apart from these major Rivers and Lakes, the continent has many other Rivers and Lakes to handle the drainage need of Africa. Some of them not earlier mentioned are;
1) Benue or Binue, river, west central Africa, the main tributary of the Niger River. It rises in northern Cameroon, flows west across central Nigeria, and joins the Niger 483 km (300 mi) from the coast. Its width varies from about 488 to 976 m (about 1600 to 3200 ft), and its navigable length is 1,000 km (600 mi) during the wet season. It is 1,400 km (870 mi) long.
2) Chari or Shari, river of the Central African Republic and Chad. It is formed by the Bamingui and Gribingui rivers 169 km (105 mi) west of Ndélé in northern Central African Republic, and flows northwest for 950 km (590 mi), joining with the Logone River at N'Djamena in Chad and entering Lake Chad in a wide delta. It is the chief affluent of Lake Chad. Navigation for small river steamers is possible only at certain times of year.
3) Jubba or Genalē, river that rises in the highlands of south central Ethiopia and flows 1,660 km (1,030 mi) to the Indian Ocean coast in Somalia. It is known as the Genalē in Ethiopia and as the Jubba in Somalia.
4) Kafue, river in central Zambia, a tributary of the Zambezi River. The Kafue is 950 km (590 mi) long. From its source in the Copperbelt near the border of the Democratic Republic of the Congo, the Kafue flows southeast through hilly terrain to Kitwe, then southwest to Kafue National Park, where it turns south, forming part of the park's eastern border. At Meshi Teshi Gap, the river turns sharply east and continues through the Kafue Flats. From just south of Lusaka where the Kafue is dammed, the river drops about 700 m (about 2,300 ft) through the Kafue Gorge. Kafue Dam (1968-1972) impounds Kafue Gorge Reservoir. It has a generating capacity of 900,000 kilowatts, making Zambia self-sufficient in hydroelectricity and providing surplus power for export to neighboring countries. The Kafue continues east to join the Zambezi at the Zimbabwe border. Navigation on the river is restricted by waterfalls and rapids.
5) Kasai, river, south central Africa, chief southern tributary of the Congo River. The Kasai rises in the central highlands of Angola and flows 2,153 km (1,338 mi) north to the Congo River. The river forms part of the boundary between Angola and the Democratic Republic of the Congo (DRC, formerly Zaire). Most of the rivers and streams of the Kasai River system flow from south to north. The chief tributaries of the system are the Fimi, Sankuru, Lulua, and Kwango Rivers. The system is navigable by steamboat for more than 2410 km (more than 1500 mi).
6) Lualaba, river, the Democratic Republic of the Congo (DRC, formerly Zaire), the upper reaches of the Congo River. It rises in the southeastern part of the country and flows 1,800 km (1,100 mi) north to Stanley Falls, where the Lualaba becomes the Congo River. Among the major tributaries of the Lualaba are the Lukuga and Luvua rivers.
7) Ubangi, also called the Oubangui, river of central Africa, the chief tributary of the Congo River, formed by the confluence of the Uélé and Mbomou rivers at Yakoma in northern Democratic Republic of the Congo (DRC, formerly Zaire). The river flows generally northwest, forming the border between the DRC and the Central African Republic. Near Fort de Possel, Central African Republic, the Ubangi turns southwest, and then flows between the DRC and the Republic of the Congo. The Ubangi, which is 1,130 km (700 mi) long, enters the Congo River near Lake Tumba in northwestern DRC. The Ubangi is navigable for 600 km (370 mi) from its junction with the Congo to Bangui, in the Central African Republic.
8) Vaal, river, South Africa, rising in the Drakensberg Mountains, on the border of Swaziland, and flowing west and southwest along the northern border of the province of Free State to its junction, after a course of some 1,160 km (720 mi), with the Orange River.
9) Volta, river in Ghana, formed by the confluence of the Black Volta and White Volta rivers at Yeji in the central part of the country, and flowing in a southerly course through Lake Volta, Ghana, to Ada, on the Gulf of Guinea. The total length, including the Black Volta, is 1,500 km (930 mi). Lake Volta was created by the construction of the Akosombo Dam on the river in the mid-1960s. At about 8482 sq km (about 3275 sq mi), the lake is one of the largest artificially created lakes in the world. The Akosombo Dam and another dam built in 1981 at Kpong, 8 km (5 mi) downstream, produce enough power to meet Ghana's electricity needs.
Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.
It is important to note that most of the other small rivers joined the major big ones earlier mentioned above.
CLIMATE
African climate is influenced by these three major factors. According to Jasper H. Stembrigbe, there factors can be placed this way.
1) As three-quarters of Africa lies within the tropics, the greater part of the continent is hot, though in many regions, especially in the south-east, the elevation somewhat moderates the actual temperature.
2) Since the Equator almost bisects Africa, we may expect to find somewhat similar climatic condition on the either side, though we must not forget that the seasons are reversed, and thus, for example, when the north is having its summer, the south is having its winter. There is, its is true, a great climatic similarity, but the actual conditions are somewhat modified by (a) the much greater breadth of the north which lessens the oceanic influence in the region, and causes the climatic belts to be more extensive than those in the south; and (b) the presence of the great land mass of Asia to the north-east of the continent.
3) The cool Benguale Current, flowing northwards along the south-west coast, greatly reduces the temperature of the region. The Canaries Current cools the west coast of North-Africa. The warm Guinea Current brings great heat and moist to the coast lands of the Gulf of Guinea.

TEMPERATURE
According to Jasper Stembridge, in July the sun is vertically overhead near the Tropic of Cancer and the hottest part of the continent lies north of the Equator, where the temperature over the greater part of the Sahara and the Nile Valley is 90oF. In the Sahara itself, owing to the lack of protective covering and the absence of cloud, the ground gains and losses heat rapidly. Thus the daily range of temperature is great. South of the Equator, July is one of the cool season months. Cape Town has a July temperature of 55o F, and thus is approximately as warm as the north of Scotland in summer.
Gradually the sun appears to move south, and heat equator swings south too, but it moves more slowly than the sun because, though land heats more quickly than water, it takes some time to become really hot.
In January sun is vertically overhead in the south of Africa and the hottest region lie south of the Equator. The belt of maximum heat, 90oF, is in the south-east. The North is now the coolest part of the continent. The January temperature at Algeria is 53oF, compared with 69oF (summer) at Cape Town.
In the equatorial belt, temperatures are uniformly high throughout the year, and the annual range is small.
WINDS AND RAINFALL
In Africa, the high-pressure belts, with their outflowing winds stretch across the north and south of the continent, while the low-pressure belt lies about the Equator. All these belts move north and south with the sun. The north-east and south-east trades always blow from the high-pressure belts towards the low-pressure belt, and they are blowing form the cooler to warmer regions their capacity for absorbing moisture from the land over which they pass. So in the Northern Africa the north-east trade winds blowing across a great land mass are dry and their dryness becomes greater as they pass over the land: hence in the trade-wind zone there is the great desert belt of the Sahara extending from the Atlantic to the shore of the Red Sea. In the high-pressure of the south of Africa, the south-east trades blow over the Indian Ocean and on reaching the eastern side of the continent brings rain to the windward slopes of the plateau. The Kalahari arid region is much smaller, both on account of the lesser breadth of the southern part of the continent, and because of the rainy region to the east. Though often termed a desert, the Kalahari is by no means a waterless area, such as the Sahara.
When the winds, blowing towards the equatorial low-pressure belt meet, then the current of heated moisture –laden air rise, and being cooled by expansion cause heavy convectional rains in this region. Rainsfall throughout the year but is heaviest shortly after the equinoxes in March to September. The equatorial rains follow the sun and a marked dry season which increases in length towards the desert margin.
In the northern summer the wind belts have shifted somewhat towards the north. The regions of the greatest rain lie north of the Equator: the coast-lands of the Gulf of Guinea and the Cameroun are now two of the wettest part of the continent.
REFERENCE
Most of information in this write up are gotten from the book: The World, a general regional geography, by Jasper H. Stembridge. Oxford University Press, 1956.
Some facts were copied from Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.