Most of the northern third of Africa and the adjacent Middle East has landscapes that are the product of past and current arid to semi-arid conditions. Desert dominates most of northern Africa. The central third of Africa in many places is much more heavily vegetated, including tropical rainforests. The southern third of that continent again reverts to semi-arid conditions in which savannah vegetation is particularly common. Much of Asia Minor and the Middle East bears resemblance to landscapes similar to northern Africa.
Africa is a continent noted for its stark varieties of diverse landscapes. While there are relatively few large cities, and many nations are still in the third world underdeveloped category, populations of pluralistic ethnic groups are distinctive. We will establish a framework for viewing Africa using the next three illustrations. The first sets the geographic boundaries of its many nations:
The next pair show a construction of the main surface cover types (desert, forest, savannah, etc.) and a classification of the principal types.
We will begin our journey through Africa in its northwestern sector. Shown first is the Anti-Atlas mountains of southern Morocco. These are known locally as the Jebel Bani. The Atlas and Anti-Atlas Mountains of northwestern Africa, seen earlier on page 2-6, are a collision-fold belt similar to the Appalachians. The region is sparsely populated and experiences low rainfall.
Many people, influenced by movies, visualize the African desert as never-ending sand dunes. This next scene, in south-central Algeria, is in fact a more typical expression of the Sahara Desert. In the lower left third is the Tademait Plateau, underlain by sedimentary rocks, and crossed by dendritic intermittent streams whose channels were cut during a wetter epoch in the Pleistocene. The land in the lower right is the Tidikelt, a barren gravel-surfaced plains. The upper part of the image is a segment of the Grand Erg Orientale, whose most prominent feature is the series of longitudinal dunes first established when the wind blew more from west to east than today. This whole region is almost uninhabited.
Yet the hallmark of the Sahel (another term for Sahara) is the absence of notable vegetation, so that the desert from a distance looks like a great expanse of sand and soil having a characteristic yellow to orangish color overall, without much diversity of features when an image is low resolution. This Envisat image shows these characteristics; the scene extends from the Anti-Atlas Mountains on the north to the Inland Delta of the Niger to the south (individual Landsat images show these areas on this page).
Desert people make up much of Mali's population. The country is crossed by the Niger River on its way to the bottom of the western hump of Africa. During the rainy season water spreads over the flat lands producing an "inland sea" of sorts. This feature is actually referred to as the Inland Delta of Mali. The water in this scene is black, with thick wetlands vegetation in red. The Bambara and Peuhl peoples farm the area and raise Zebu cattle.
Africa conjures up an image to many as a vast dense jungle. However, most of the continent is ecologically either a savannah (brush and grasslands) or a desert similar to the type in the image just above. But, in the "Congo", much of that region being in today’s Zaire, a true jungle (Tarzan type) - much like that in the Amazon - of continuous rain forest made up of teak, ebony, copal, palm, and cedar trees remains one of the pristine timber regions of the world, although deforestation is now underway. Here in this Landsat MSS false color scene, this status is disclosed by the solid expanse of red (= NearIR) vegetation; usually the region is largely cloud-covered but this clear March 1973 scene is unusual. The large river crossing the scene is the Congo (renamed the Zaire) River; the large tributary is the Aruwimi. The Congo is 4370 km (2718 miles) in length, making it one of the longest on Earth; it is navigable far upstream.
However, the tropical forests are shrinking and desertification from the Sahara is moving south. Some of this loss is natural but much has resulted from land clearing by the indigenous tribes. Here is a Landsat view of part of Ghana and Togo, in which once dominant rain forest has been removed by cutting and burning, converting the land to savannah. The dark areas are probably burn scars from recent burns.
But, the still extensive forestlands offer shelter to many of the indigenous (but to zoo-goers, exotic) animals, such as the African gorilla. Radar imagery helps to penetrate the tropical growth, as shown in this SIR-C image of Lake Kiva and parts of Rwanda, Uganda, and Zaire. One prominent volcano is Mt. Karisembi:
This next scene covers part of northern Kenya in East Africa. The capital, Nairobi, lies at the right margin about one-third down from the top (it is a bluish area midst the red). The dominant feature running north-south through the right half of the image is the African Rift Valley, shown here in dark bluish-gray representing basaltic rocks. Notable are the many scarps caused by normal faulting as the rift develops and pulls apart. (See page 2-9 for another example of this rift terrain.) Small volcanoes dot the Valley. The lake at the bottom is Lake Natron, whose level varies seasonally, and as it dries leaves sodium carbonate deposits. The lake at the top of the Valley is Lake Naivasha. Relief in the region exceeds 1000 meters (several thousand feet), so that higher elevations remain forested whereas lower areas are near-desert. Rain around Nairobi up to 100 cm (40 inches) gives that area enough moisture to support crop farming, including coffee planation.
The African continent is mountainous as well. You saw the highest peak in Africa, Mount Kilimanjaro, a huge volcano, in the Game subsection. Because the coloring is so attractive, we show it again in this Landsat image which covers a larger area:
In Tanzania, between Lake Victoria (next page) and the volcanoes west of Kilimanjaro lies the Serengeti National Preserve, one of the most stupendous game lands in the world. The park is largely flat plains, as depicted in this SRTM topographic image; the volcano is Ngorongoro:
This Landsat subimage gives a further impression of the grasslands terrain:
This is a typical photo of the Serengeti landscape.
The wildlife is diverse, plentiful, and often spectacular. Lions, elephants, giraffes, hippos, and many other varieties of African animals we have associated with this continent abound. As shown in the next two photos, herds of wildebeests, and large white birds (egrets?) and zebras attest to the fauna people come to this part of Africa to observe on Safari.
Within the Serengeti lies an ephemeral river that has carved out the Olduvai Gorge from Pliocene-Pleistocene sediments. Here is the famous location where the Leakey family and their associate anthropologists have made some of the great discoveries of hominids dating back more than a million years. This ASTER space image shows some details of the immediate area:
Small parts of four countries - Zambia, Botswana, Zaire, and Namibia - appear in this Landsat image. The Zambesi River flows through the Kalahari Basin whose vegetation is a savannah grasslands and some swamps.
Typical savannah land cover (here called the Veld) is dominant in this Landsat image of southwestern Botswana. The mottled pattern is largely the result of controlled brush and grass fires to prepare the land for later planting. The Kalahari Bushmen inhabit the region.
Further to the southwest along the Atlantic is Namibia, a barren land of deserts and treeless mountains. This is the Kaoko Veld region. The eroded fold belt mountains contain rocks of the Damara and Karoo systems:
In this next scene, near the coast in southeastern South Africa, is another fold belt known as the Cape Ranges, a collection of anticlines and synclines running about east-west, and made up of Paleozoic rocks. In places, their elevation exceeds 1500 m (5000 ft). The dark reds associated these mountains imply forests that include evergreens. They block winds coming from the Indian Ocean (lower right) so that precipitation is "wrung out" over them (up 130 cm or 50 inches annually), leaving the interior (left) in a rain shadow that fosters a semi-arid desert flora. Along the top of the scene is the Great (or Drakensberg) Escarpment, a steep cliff nearly 1.5 km (1 mile) high on top of which is a vast peneplain referred to as the Post-Gondwana Surface, dating from the Cretaceous Period. Elevations above the escarpment reach to 2400 m (8000 ft). The region is harsh for living, with low populations.
A continuation of the Cape Ranges carries one to Cape Town (blue area in center left) and the southernmost tip of Africa, as seen in this Landsat view:
Compare this overhead scene with a close-up ground photo of Cape Town
Finally, we show part of a MISR image that features the largest city in South Africa, Johannesburg, which lies in the heart of the Witwatersand - which contains the main gold-producing fields (numerous underground mines) on the continent:
Compare this with this photo taken by astronauts aboard the International Space Station:
The final South African city we will look at is Pretoria, as seen in this Landsat-7 image.