The lands of Africa

Africa countries

Behind the northern coastal belt, in terms of landscape connection with Southern Europe and Western Asia, starting with the Sahara desert, the continent's hard-to-reach interior stretches. Huge mountain ranges rise above the desert plates – Ahaggar, Adrar des Iforas, Air and high on 3415 m n.p.m. Tibesti, which separate the western Sahara from the Libyan Desert. The vast plains of Egypt, Sudan and Libya appear monotonous and barren plateaus, significantly elevated above sea level (on average several hundred, and locally over 1000 m n.p.m.). On the other side of the Nile valley, the Arab and Nubian deserts form an extension of the Libyan Desert, reaching the shores of the Red Sea.

South of the desert belt is the strip of Sudan's steppes. The vast basins of this land, separated by massifs and lofty rapids, are drained by the Niger and the rivers flowing to Chad by a huge bowl with banks bent outwards and raised upwards. The edge of the highlands, suspended above a narrow coastal strip, forms a steep mountain cliff, hindering access to the interior of the continent. Wide, overgrown the Katan-ga-Lunda threshold with savannah, drained eastwards by the Zambezi River, goes into a smaller one, the drainless and semi-desert Kalahari sand basin. Further to the east, there are extensive ones, mostly covered with low grasses and shrubs in the Transvaal and Orania plains, drained by the rivers Oranje and Limpopo. From the south, Africa is closed by the Cape Mountains, and from the south-east – through the Drakensberg Mountains. At the western end it is wide 100 km coastal Namib desert. The highlands of East Africa are crisscrossed by huge tectonic ditches, filled by numerous and deep lakes.

Unique atmosphere

In Africa, they go one after another (advancing north and south from the equator) all zones of the inter-tropical climate: equatorial, extremely humid, equatorial variable wet (moist and dry), tropical dry and extremely dry and subtropical. On the shores of the Gulf of Guinea there is an extremely humid equatorial climate - rainfall is very high (exceeding significantly 5000 mm per year), and the rainy season lasts even over 9 months. In areas with annual rainfall 1000-1500 mm and lasting dry season 4-6 months there is a humid equatorial climate. Precipitation areas 500-1000 mm and dry season from 7 do 9 months is a zone of dry equatorial climate (characteristic, among others. for Sudan). Originally narrow stretches along the southern tip of the Sahara desert, but from year to year the transition zone expands – sahel. There is a tropical continental climate here (dry) – annual rainfall is 200-500 mm, and the dry season continues 9-10 months. These areas are covered with a typical thorny savannah (semi-desert, sahelska) with a few thorny bushes and trees (mainly acacia trees). Low grasses predominate, often in large clumps, but usually bare ground covers more than half the area. Sahara is a separate climatic province, which is characterized by an extremely sparse vegetation – extremely low rainfall and high temperatures inhibit vegetation.

A hot continent

Africa's water relations are particularly closely linked to the climate. The permanent river network and the largest water systems of the continent occur in the equatorial zone. In tropical zones, rivers disappear and reappear in areas with a Mediterranean climate, but they have significant fluctuations in flows over the year. The division of the continent into valleys corresponds to river systems, which flow concentrically to the bottom of the depressions, e.g.. Congo system, upper Zambezi and Kubango in the Kalahari Basin. The Nile has a separate nature of a transit river with a complex regime, originating in the equatorial zone. Fed upstream by tributaries flowing from the Abyssinian Plateau, it makes its way through the Sahara desert upstream and downstream, losing a significant part of its water on the way to evaporation. In this section, the river owes its existence to the supply of groundwater. The Blue Nile draws its water from the Abyssinian monsoons – it is reflected in seasonal changes in the water level in the river and causes its regular flooding. The White Nile, in its upper reaches in Sudan, divides into numerous arms and creates great pools in this zone, which in tropical climates are immediately covered with a dense carpet of plants. Great rivers flowing through internal valleys and sills break through gorges into the sea, creating numerous waterfalls, which hinder navigation and penetration inland.