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6.1. African Group
Africa region has significantly contrasting natural habitats and ecosystems,
geological and topographic configurations, climates (mostly arid and semiarid with
permanent or semi-permanent hot and dry conditions) and patterns of settlements. This
physical variation encompasses a wide range, for instance, desert and semi-desert areas
that are virtually uninhabited (except for scattered oases) and constitutes more than
80 % of the total area of the Arab homeland (Barakat, 1993).
Annual average precipitation received by African Group of Countries changes
according to their location and climate conditions. Especially, precipitation of Sierra
Leone was the highest (2,526 mm). Annual precipitation of Niger, Chad and Mali were
lower than the other African countries (Figure 6.2).
The African Group countries are apparently characterized with various climates,
regions and zones. According to the Köppen-Geiger climate classification and the
UNCCC aridity index (Türkeş, 2010, 2012), the tropical northern half of the Africa
continent has primarily dry climate of semi-arid steppe and arid desert or semi-desert
lands, while its central and southern areas contain both tropical savanna and tropical
moist (rainforest) climate regions. Between these macro climate regions, there is a
convergence, where biome patterns such as Sahel and steppe dominate. The seasonal
summer movement of the ITCZ creates and controls a rainy season in summer across
central portions of the continent to the south of the Sahara and the north of southern
Africa. The Sahara desert region is the hottest and driest portion of the Africa continent
due to the presence of the subtropical high pressure system, and the subsidence and
stability during most of the year associated with this system.
In summary, according to the Köppen-Geiger climate classification and the
UNCCC aridity index (Türkeş, 2010, 2012; Türkeş et al., 2011), the African continent
as a large land mass existing across Equator and surrounded largely by ocean and sea
masses has a wide variety of climates.
Tropical rainforest climate is found particularly in the center of the equatorial
continent and also along the eastern coast of Madagascar.