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In West Africa, the Dahomey Gap refers to the portion of the Guinean forest-savanna mosaic that extends all the way to the coast in Benin, Togo, and Ghana, thus separating the forest zone that covers much of the south of the region into two separate parts. The forest region west of the gap is called the Upper Guinean forests or Guinean forest zone, and the portion east of the gap is called the Lower Guinean forests, Lower Guinean-Congolian forests, or Congolian Forest Zone.
The major city in the Gap is Accra. Several other cities, such as Kumasi, exist on the fringe of the Gap.
The dryness of the Dahomey Gap is unusual, given that it lies surrounded by a very wet monsoon belt on all sides, and no mountains block moisture. Yet, Accra, which is in the heart of the Gap, receives only 720 mm (28 in) of rainfall per year — less than half the amount needed to sustain tropical rainforest (which would be expected at a latitude of 6° N).
The cause of the dryness of the Dahomey Gap can simply be explained thus:
Evidence from biogeography suggests that the Dahomey Gap has had significance for up to 90 million years. Murphy and Collier, in their analysis of the Aplocheiloid fishes show a split in the African species which they attribute to the presence of an epicontinental sea between the late Cenomanian and early Eocene.This discontinuity had earlier been noted in plant species by White and is supported by an analysis of the Coffea clade by Maurin et al.
The Dahomey Gap has existed in its present form for only about four thousand years.For most of the Quaternary, dry conditions due to a much colder Atlantic Ocean (aided by extensive cold currents from ice sheets in Europe and North America) have meant that the present-day forest zone has supported very little or no rainforest. In interglacial periods, however, rainfall throughout West Africa has often been so heavy that the Gap has become wet enough to support rainforest, thus eliminating the savanna.
Cape Verde is a group of arid Atlantic islands which are home to distinct communities of plants, birds, and reptiles. The islands constitute the unique Cape Verde Islands dry forests ecoregion, according to the World Wildlife Fund.
Nigeria is a country in West Africa. Nigeria shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in the north. It also shares a border with the self-declared, but internationally unrecognized state of Ambazonia in the southeast. Its coast lies on the Gulf of Guinea in the south and it borders Lake Chad to the northeast. In the southeast, it also shares a border with the breakaway state of Ambazonia. Noted geographical features in Nigeria include the Adamawa highlands, Mambilla Plateau, Jos Plateau, Obudu Plateau, the Niger River, River Benue and Niger Delta.
The Afrotropical realm is one of Earth's eight biogeographic realms. It includes Africa south of the Sahara Desert, the majority of the Arabian Peninsula, the island of Madagascar, southern Iran and extreme southwestern Pakistan, and the islands of the western Indian Ocean. It was formerly known as the Ethiopian Zone or Ethiopian Region.
Tropical climate is one of the five major climate groups in the Köppen climate classification. Tropical climates are characterized by monthly average temperatures of 18 ℃ (64.4 ℉) or higher year-round and feature hot temperatures. Annual precipitation is often abundant in tropical climates, and shows a seasonal rhythm to varying degrees. There are normally only two seasons in tropical climates, a wet season and a dry season. The annual temperature range in tropical climates is normally very small. Sunlight is intense.
The wet season is the time of year when most of a region's average annual rainfall occurs. Generally, the season lasts at least a month. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the tropics and subtropics.
In West Africa, the forest zone refers to the southern part of the region once covered by tropical rainforest. Sometimes this region is referred to as Guinea to distinguish it from the grassland-covered Sudan, drier Sahel and per-arid Sahara.
In physical geology, aspect is the compass direction that a slope faces. For example, a slope on the eastern edge of the Rockies toward the Great Plains is described as having an easterly aspect. A slope which falls down to a deep valley on its western side and a shallower one on its eastern side has a westerly aspect or is a west-facing slope. The direction a slope faces can affect the physical and biotic features of the slope, known as a slope effect. The term aspect can also be used to describe the shape or alignment of a coastline. Here, the aspect is the direction which the coastline is facing towards the sea. For example, a coastline with sea to the northeast has a northeasterly aspect.
The Upper Guinean forests is a tropical seasonal forest region of West Africa. The Upper Guinean forests extend from Guinea and Sierra Leone in the west through Liberia, Côte d'Ivoire and Ghana to Togo in the east, and a few hundred kilometers inland from the Atlantic coast. A few enclaves of montane forest lie further inland in the mountains of central Guinea and central Togo and Benin.
The Lower Guinean forests is region of coastal tropical moist broadleaf forest in West Africa, extending along the eastern coast of the Gulf of Guinea from eastern Benin through Nigeria and Cameroon.
The Guinean forest-savanna mosaic is an ecoregion of West Africa, a band of interlaced forest, savanna, and grassland running east to west and dividing the tropical moist forests near the coast from the West Sudanian savanna of the interior.
The Congolian rainforests are a broad belt of lowland tropical moist broadleaf forests which extend across the basin of the Congo River and its tributaries in Central Africa.
Forest-savanna mosaic is a transitory ecotone between the tropical moist broadleaf forests of Equatorial Africa and the drier savannas and open woodlands to the north and south of the forest belt. The forest-savanna mosaic consists of drier forests, often gallery forest, interspersed with savannas and open grasslands.
The monsoon trough is a portion of the Intertropical Convergence Zone in the Western Pacific, as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and northern hemispheres.
A tropical marine climate is a tropical climate that is primarily influenced by the ocean. It is usually experienced by islands and coastal areas 10° to 20° north and south of the equator. There are two main seasons in a tropical marine climate: the wet season and the dry season. The annual rainfall is 1000 to over 1500 mm. The temperature ranges from 20 °C to 35 °C. The trade winds blow all year round and are moist, as they pass over warm seas. These climatic conditions are found, for example, across the Caribbean; the eastern coasts of Brazil, Madagascar and Queensland; and many islands in tropical waters.
Although tropical Africa is mostly familiar to the West for its rainforests, this biogeographic realm of Africa is far more diverse. While the tropics are thought of as regions with warm to hot moist climates caused by latitude and the tropical rain belt, the geology of areas, particularly mountain chains, and geographical relation to continental and regional scale winds impact the overall parts of areas, also, making the tropics run from arid to humid in West Africa. The area is experiencing negative effects of rapid human population growth.
The wildlife of Togo is composed of the flora and fauna of Togo, a country in West Africa. Despite its small size the country has a diversity of habitats; there are only remnants of the once more extensive rain forests in the south, there is Sudanian Savanna in the north-western part of the country and larger areas of Guinean forest-savanna mosaic in the centre and northeast. The climate is tropical with distinct wet and dry seasons. There are estimated to be over 3000 species of vascular plant in the country, and 196 species of mammal and 676 species of bird have been recorded there.
An area of tropical monsoon climate is a type of climate that corresponds to the Köppen climate classification category "Am". Tropical monsoon climates have monthly mean temperatures above 18 °C (64 °F) in every month of the year and a dry season. Tropical monsoon climates is the intermediate climate between the wet Af and the drier Aw.
Earth rainfall climatology Is the study of rainfall, a sub-field of meteorology. Formally, a wider study includes water falling as ice crystals, i.e. hail, sleet, snow. The aim of rainfall climatology is to measure, understand and predict rain distribution across different regions of planet Earth, a factor of air pressure, humidity, topography, cloud type and raindrop size, via direct measurement and remote sensing data acquisition. Current technologies accurately predict rainfall 3–4 days in advance using numerical weather prediction. Geostationary orbiting satellites gather IR and visual wavelength data to measure realtime localised rainfall by estimating cloud albedo, water content, and the corresponding probability of rain. Geographic distribution of rain is largely governed by climate type, topography and habitat humidity. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation. On the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. The movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to Savannah climes. The urban heat island effect leads to increased rainfall, both in amounts and intensity, downwind of cities. Warming may also cause changes in the precipitation pattern globally, including wetter conditions at high latitudes and in some wet tropical areas. Precipitation is a major component of the water cycle, and is responsible for depositing most of the fresh water on the planet. Approximately 505,000 cubic kilometres (121,000 cu mi) of water falls as precipitation each year; 398,000 cubic kilometres (95,000 cu mi) of it over the oceans. Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres (39 in). Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes.
Seasonal tropical forest, also known as moist deciduous, semi-evergreen seasonal, tropical mixed or monsoon forests, typically contain a range of tree species: only some of which drop some or all of their leaves during the dry season. This tropical forest is classified under the Walter system as (ii) tropical climate with high overall rainfall concentrated in the summer wet season and dry season: representing a range of habitats influenced by monsoon (Am) or tropical wet savannah (Aw) climates. Drier forests in the Aw climate zone are typically deciduous and placed in the Tropical dry forest biome: with further transitional zones (ecotones) of savannah woodland then tropical and subtropical grasslands, savannas, and shrublands.
The Guineo-Congolian region is a biogeographical region in Africa straddling the Equator and stretching from the Atlantic Ocean through the Congo Basin to the Congo / Nile divide in Rwanda and Burundi. Formerly, this region was largely covered in rain forest, on both well-drained sites and in swamp forests, but little undisturbed primary forest now remains, having been replaced in many areas by savanna and secondary-growth forest.