Sahara ( UK: , ; Arabic: ??????? ?????? ?, a? -? a? r? 'al-kubrÃÆ'¡ ,' the Great Desert ') is the greatest desert and the third largest desert in the world after Antarctica and the Arctic. Its area of ​​9,200,000 sq. Km, mi) is comparable to that of China or the United States. The name 'Sahara' comes from the Arabic dialect for "desert", ? A? Ra ( ???? /'s? Ra/).
The desert consists mostly of North Africa, excluding the fertile areas of the Mediterranean Sea coast, the Atlas Mountains in the Maghreb, and the Nile Valley in Egypt and Sudan. It stretches from the Red Sea to the east and the Mediterranean Sea in the north to the Atlantic Ocean to the west, where the landscape gradually changes from desert to coastal plains. To the south, it is bordered by Sahel, a semi-arid tropical grass belt around the Niger River basin and the Sudanese Region in Sub-Saharan Africa. The Sahara can be divided into several areas including: Western Sahara, Central Ahaggar Mountains, Tibesti Mountains, AÃÆ'¯r Mountains, desert TÃÆ'Ã… © nÃÆ'Ã… © rà © Ã… ©, and Libyan Desert.
For several hundred thousand years, the Sahara has alternated between the desert and savanna grasslands in a 41,000-year cycle caused by changes ("precession") on Earth's axis as it rotates around the sun, changing the location of the North African Monson. It is further expected to be green in about 15,000 years (17,000 AD).
Video Sahara
Geography
The Sahara covers most of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, Western Sahara, Sudan and Tunisia. It covers 9 million square kilometers (3,500,000 sqc, mi), 31% of Africa. If all regions with an average annual rainfall of less than 250 mm are included, the Sahara would be 11 million square kilometers (4,200,000 sq./n mi). It is one of three different physiographic provinces of the great African physiographic division.
The Sahara is a particularly rocky hamada (rock plain), Ergs (sea sand - large area covered with sand dune) forms only a small section, but many dunes are over 180 meters (590Ã, ft) tall. Uncomplicated wind or rainfall forms desert features: sand dunes, sand dunes, sand oceans, rock plates, gravel plains ( reg ), dry valleys (wadi ), lakes dry ( oued ), and flat salt ( shatt or chott ). Unusual landscapes include the Richat Structure in Mauritania.
Some very deep mountains are dissected, many volcanoes, rise from the desert, including the AÃÆ'¯r Mountains, Ahaggar Mountains, Sahara Atlas, Tibesti Mountains, Adrar des Iforas, and Red Sea hills. The highest peak in the Sahara is Emi Koussi, a volcano shield in the Tibesti range in northern Chad.
Middle Sahara is hyperarid, with sparse vegetation. The northern and southern parts of the desert, along with the plateau, have rare grassland areas and desert bushes, with trees and shrubs higher in the wadi, where moisture is collected. In the center, the hyperarid area, there are many large desert subdivisions: Tanezrouft, TÃÆ'Ã… © nÃÆ' © ©, Libyan Desert, Eastern Desert, Nubian Desert, and others. These very dry areas often do not receive rain for years.
To the north, the Sahara encircles the Mediterranean Sea in Egypt and parts of Libya, but in Cyrenaica and Maghreb, the Sahara is bordered by the Mediterranean forests, forests, and scrubs of northern Africa, all of which have a characteristic Mediterranean climate. by hot summers and cold winters and rain. According to Frank White's botanical criterion and geographer Robert Capot-Rey, the northern boundary of the Sahara corresponds to the northern boundary of date cultivation and the southern boundary of the esparto range, the typical grass of the Mediterranean climate part of the Maghreb and Iberia. The northern boundary also corresponds to the annual rainfall isohyet of 100 mm (3.9 inches).
In the south, the Sahara is bordered by Sahel, a tropical savanna belt with a summer rainy season that extends across Africa from east to west. The southern boundary of the Sahara is botanically indicated by the southern boundary of the Cornulaca monacantha (drought-tolerant Chenopodiaceae), or northern boundary of Cenchrus biflorus, the typical grass of the Sahel. According to climate criteria, the southern boundary of the Sahara corresponds to an annual rainfall isohyet of 150 mm (5.9 inches) (this is a long-term average, since rainfall varies every year).
Important cities located in the Sahara include Nouakchott, the capital of Mauritania; Tamanrasset, Ouargla, BÃÆ'Ã… © char, Hassi Messaoud, GhardaÃÆ'¯a, and El Oued in Algeria; Timbuktu in Mali; Agadez in Niger; Ghat in Libya; and Faya-Largeau in Chad.
Maps Sahara
Climate
The Sahara is the world's largest latitude hot desert. This area lies in the horses' latitude under subtropical ridge, a significant belt of subtropical warm-semi-permanent high-core pressure where air from the upper levels of the troposphere tends to sink to the ground. This steady decreased air flow causes warming and drying effects in the upper troposphere. The drowning air prevents water evaporation from rising and, therefore, prevents adiabatic cooling, which makes cloud formation extremely difficult almost impossible.
Permanent cloud dissolution allows uninterrupted light and thermal radiation. The atmospheric stability over the desert prevents any inverse conviction, thus making the rain almost non-existent. As a result, the weather tends to be bright, dry and stable with minimal risk of rainfall. Constrained, diverging, dry air mass associated with subtropical high-pressure systems is highly unfavorable for the development of convection rain. Subtropical ridge is a major factor explaining the hot desert climate (climatic classification KÃÆ'¶ppen BWh ) of this vast region. The air decrease is the strongest and most effective in the eastern part of the Great Desert, in the Libyan Desert which is the brightest, dryest and almost "no rain" place on the planet that rivals the Atacama Desert, lying in Chile and Peru.
Rainfall inhibition and cloud cover dissipation are most prominent in eastern Sahara rather than west. The air mass above the Sahara is the mass of tropical continental air (cT), which is hot and dry. The hot dry air mass mainly forms above the desert of North Africa from the heating of the continental land area, and it affects the entire desert for most of the year. Due to this extreme heating process, the lowest temperatures are usually seen near the surface, and are the strongest and most developed during the summer. The Sahara High represents the east continent extension of the Azores High, centered on the North Atlantic Ocean. The decline of Sahara High almost reached the ground during the coolest part of the year while it was confined to the upper troposphere during the hottest period.
The effects of low local surface pressure are very limited because the upper level decline still continues to block any form of air rise. Also, in order to be protected from the rainy weather system by the atmospheric circulation itself, the desert is made drier by geographic configuration and its location. Indeed, the extreme arias of the Sahara can not be explained only by subtropical high pressure. The Atlas mountains, found in Algeria, Morocco, and Tunisia also help increase the desertness of the northern part of the desert. This main mountain range acts as a barrier that causes a powerful rainbow effect on the underside of the wind by dropping much of the moisture brought about by atmospheric disturbances along the polar fronts affecting the surrounding Mediterranean climate.
The main source of rain in the Sahara is the Intertropical Convergence Zone, a continuous low-pressure belt system near the equator that brings short, short and irregular rainy seasons to the Sahel and southern Sahara. Rainfall in this giant desert must overcome the physical and atmospheric obstacles that usually prevent the production of sedimentation. The harsh climate in the Sahara is characterized by: very low rainfall, unreliable, highly erratic; the value of the duration of sunlight is very high; high temperatures throughout the year; a negligible level of relative humidity; significant diurnal temperature variations; and the highest recorded high potential evaporation rate in the world.
Temperature
The sky is usually sunny above the desert and the duration of sunlight is very high everywhere in the Sahara. Most of the desert has more than 3,600 hours of bright sunlight every year or more than 82% of the time, and the vast area in the east has more than 4,000 hours of bright sunlight a year or more than 91% of the time. The highest value is very close to the theoretical maximum value. A score of 4,300 hours or 98% of the time will be recorded in Upper Egypt (Aswan, Luxor) and in the Nubian Desert (Wadi Halfa). The average annual direct sun exposure is about 2,800 kWh/(m 2 year) in the Great Desert. The Sahara has great potential for solar energy production.
The ever-high sun position, very low relative humidity, and the lack of vegetation and rainfall make the Great Desert the continent's hottest ever worldwide, and the hottest spot on Earth over the summer in some places. Average high temperatures exceed 38 to 40 Â ° C or 100.4 to 104.0 Â ° F during the hottest months of almost everywhere in the desert except at very high altitudes. The highest officially recorded highest temperature is 47 ° C or 116.6 ° F in a remote desert town in the Algerian Desert called Bou Bernous with a height of 378 meters (1,240 feet) above sea level. This is the highest recorded average highest temperature in the world and only Death Valley, California that matches it. Other hotspots in Algeria such as Adrar, Timimoun, In Salah, Ouallene, Aoulef, Reggane with altitudes between 200 and 400 meters (660 and 1,310 ft) above sea level get slightly lower summer averages around 46 Â ° C or 114.8 Ã, Â ° F during the hottest months of the year. False, famous in Algeria due to extreme heat, has an average high temperature of 43.8 ° C or 110.8 ° F, 46.4 ° C or 115.5 ° F, 45.5 ° Â ° C, or 113.9 Â ° F and 41.9 Â ° C or 107.4 Â ° F respectively in June, July, August and September. There are even hotter places in the Sahara, but they are located in very remote areas, especially in Azalai, located in the northern part of Mali. The main part of the desert experiences about three to five months when the average height exceeds 40 ° C or 104 ° F. The southern portion of the desert undergoes up to six or seven months when the high average temperatures strictly exceed 40 ° C or 104 ° C Â ° F which indicates the firmness and length of a really hot season in the Sahara. Some examples are: Bilma, Niger, and Faya-Largeau, Chad. The average annual daily temperature exceeds 20 Â ° C or 68 Â ° F everywhere and can approach 30 Â ° C or 86 Â ° F in the hottest part of the year. However, most deserts have values ​​of more than 25 ° C or 77 ° F.
The temperature of sand and soil is even more extreme. During the daytime, the temperature of the sand is very high as it can easily reach 80 Ã, Â ° C or 176Ã, Â ° F or more. The sand temperature of 83.5 ° C (182.3 ° F) has been recorded in Port Sudan. The soil temperature of 72 Â ° C or 161.6 Â ° F has been recorded in Adrar Mauritania and the value of 75 Â ° C (167 Â ° F) has been measured in Borkou, northern Chad.
Due to the lack of very low cloud cover and humidity, the desert usually displays diurnal high temperature variations between day and night. However, it is a myth that the nights are cool after a very hot day in the Sahara. The average daily temperature range is usually between 13 and 20 Â ° C or 23.4 and 36.0 Â ° F. The lowest values ​​are found along coastal areas due to high humidity and often even lower than 10 Ã, Â ° C or 18Ã, Â ° F, while the highest value is found in the inland desert areas where humidity is the lowest, especially in the southern part. Sahara. However, it is true that winter evenings can become cold as it can go down to freezing and even below, especially in areas with high altitudes. Frequency subfreezing of winter nights in the Sahara is strongly influenced by the North Atlantic Oscillation (NAO), with warmer winter temperatures during negative NAO events and cooler winters with more snow when NAO is positive. This is because a weak clockwise flow around the east side of the subtropical anthropon during the negative NAO winter, although too dry to produce more than negligible rainfall, does not reduce the cold and dry air flow from higher Eurasian latitudes to the Sahara significantly.
Precipitation
The average annual rainfall ranges from very low in the northern and southern rim of the desert to almost nothing in the middle and east. The thin northern hemisphere in the desert receives more turbidity and rainfall in the winter due to the advent of low-pressure systems over the Mediterranean along the polar front, though strongly attenuated by the effects of mountain rain shadows and average annual rainfall ranges from 100 millimeters. (4 inches) to 250 millimeters (10 inches). For example, Biskra, Algeria, and Ouarzazate, Morocco are found in this zone. The southern desert margin along the border with the Sahel receives slope and summer rainfall due to the arrival of the Intertropical Convergence Zone of the south and the average annual rainfall ranges from 100 millimeters (4 in) to 250 millimeters (10 in). For example, Timbuktu, Mali, and Agadez, Niger are found in this zone. The large hyper-arid center core of the desert is almost never affected by atmospheric or northern atmospheric disturbances and permanently remains under the influence of the most powerful anti-cyclone weather regime, and the average annual rainfall may fall to less than 1 millimeter (0.04 inch). In fact, most Sahara receive less than 20 millimeters (0.8 inches). Of the 9,000,000 sq km (3,500,000 sq. Mi) of desert land in the Sahara, an area of ​​approximately 2,800,000 square kilometers (1,100,000 sq. Mi) (approximately 31% of the total area) receives an average annual rainfall by 10 millimeters (0.4 inches or less, while about 1,500,000 square kilometers (580,000 sq. nies) (approximately 17% of the total area) received an average of 5 millimeters (0.2 in) or less. an average of nearly zero over an area of ​​about 1,000,000 square kilometers (390,000 sq./n mi) in the eastern Sahara consisting of deserts: Libya, Egypt and Sudan (Tazirbu, Kufra, Dakhla, Kharga, Farafra, Shiva, Asyut , Sohag, Luxor, Aswan, Abu Simbel, Wadi Halfa) where the long-term average is close to 0.5 millimeters (0.02 in) per year.Rain is extremely unreliable and erratic in the Sahara because rainfall varies greatly from year to year, in stark contrast to the amount of negligible annual rainfall, the rate of evaporas i annual potential is unusually high, roughly ranging from 2,500 millimeters (100 in) per year to over 6,000 millimeters (240 per year) per year across the desert. There is no other place on Earth that has dried and evaporated air as in the Sahara region. However, at least two instances of snowfall have been recorded in the Sahara, in February 1979 and December 2016, both in the town of Ain Sefra.
Desertification and prehistoric climate
The Sahara climate has experienced a great variation between wet and dry over the last few hundred thousand years, believed to be caused by long-term changes in the North African climate cycle that altered the North African monsoon path - usually southward. This cycle is caused by a 41,000-year cycle in which the Earth's tilt changes between 22 ° and 24.5 °. Currently (2000 AD), we are in a dry period, but it is expected that the Sahara will be green again in 15,000 years (17000 AD). When the rainy season in North Africa is in the strongest annual rainfall and subsequent vegetation in the Sahara region increases, resulting in a condition commonly referred to as "green Sahara". For the relatively weak North African monsoon, the opposite is true, with declines in annual rainfall and less vegetation resulting in a phase of the Sahara climate cycle known as the "Sahara desert".
The notion that the change of insolation caused by long-term changes in Earth's orbit is a controlling factor for long-term variations in the strength of monsoon patterns worldwide first proposed by Rudolf Spitaler in the late nineteenth century. This hypothesis was then formally proposed and tested by meteorologist John Kutzbach in 1981. Kutzbach's ideas about the impact of insolation on the global monsoonal pattern have been widely accepted today as a key driver of the long-term monsoonal cycle. Kutzbach never formally mentions his hypothesis and is thus referred to here as the "Orbital Monsoon Hypothesis" as suggested by Ruddiman in 2001.
During the last glacial period, the Sahara is much larger than it is today, extending south beyond its present limits. The end of the glacial period brings more rain to the Sahara, from about 8000 BC to 6000 BC, possibly because of the low-pressure area above the collapsed ice sheets in the north. Once the ice sheet disappears, the northern part of the Sahara dries up. In the southern Sahara, the drying trend was initially opposed by the monsoon, which brought more rain to the north than it is today. Around the year 4200 BC, the monsoon retreated southward to its present location, leading to a gradual descent of the Sahara. The Sahara is now as dry as it was about 13,000 years ago.
The Sahara pump theory illustrates this cycle. During the wet or "Sahara Hijau" period, the Sahara became savanna grassland and various flora and fauna became more common. After the inter-plain dry period, the Sahara area then returns to desert conditions and the flora and fauna are forced to retreat northward into the Atlas Mountains, south to West Africa, or east to the Nile Valley. It separates populations of several species in areas with different climates, forcing them to adapt, possibly giving rise to allopathic speciation.
It is also proposed that humans accelerate the drying period from 6,000 to 2500 BC by pastoralists that exceed the available pastures.
Evidence for cycles
The growth of speleothems (which requires rainwater) is detected in Hol-Zakh, Ashalim, Even-Sid, Ma'ale-ha-Meyshar, Ktora Rifts, Nagev Tzavoa Cave, and elsewhere, and allows for prehistoric rainfall tracking. The Red Sea coastal route is very dry before 140 and after 115 kya. Wet conditions appear in 90-87 kya, but still only one-tenth rainfall around 125 kya. In Speleothems the southern Negev desert does not grow between 185-140 kya (MIS 6), 110-90 (MIS 5.4-5.2), or after 85 kya or during most interglacial periods (MIS 5.1), glacial and Holocene periods. This shows that the southern part of the Negev is dry this summer.
During the Last Glacial Maximum (LGM), the Sahara desert is wider than it is now with a vastly reduced extent of tropical forest, and lower temperatures reduce the power of Hadley Cell. It is a climate cell that causes the tropical air rise from the Tropical Convergence Zone (ITCZ) to bring rain to the tropics, while the dry air is down, about 20 degrees north, flowing back to the equator and bringing desert conditions into the region.. This is related to the high level of wind blown in mineral dust, and this level of dust is found as expected in the ocean core of the tropical north Atlantic. But around 12,500 BC the amount of dust at the core in the BÃÆ'¸lling/AllerÃÆ'¸d phase suddenly slumped and showed a wetter period of conditions in the Sahara, indicating the Dansgaard-Oeschger (DO) event (sudden warming followed by slower climate cooling). The damp Saharan state has begun around 12,500 BC, with the extension of the ITCZ ​​to the north in the northern hemisphere summer, bringing wet and savanna climate conditions to the Sahara, which (apart from short dry spells associated with Younger Dryas ) peaked during the maximum thermal climate phase of Holocene at 4000 BC when the middle latitudinal temperature seemed to be between 2 and 3 degrees warmer than in the past. The analysis of the Nile River sediment deposition in the delta also shows this period has a higher proportion of the sediments derived from Blue Nile, suggesting higher rainfall also in the Ethiopian Plateau. This is mainly due to the stronger monsoonal circulation throughout the sub-tropical region, affecting India, Arabia and the Sahara. Lake Victoria has recently become the source of the White Nile and dried up almost entirely around 15 kya.
The sudden sudden movement of ITCZ ​​to the south with the Heinrich event (sudden cooling followed by slower heating), is associated with a change in the Southern Oscillation El Nià ± o cycle, leading to rapid drainage in the Sahara and Arabian regions , which quickly became a desert. This is associated with marked declines in the Nile flood scale between 2700 and 2100 BC.
Ecoregions
Sahara consists of several different ecoregions. With their variations in temperature, rainfall, altitude, and soil, this area has different plant and animal communities.
The Atlantic coastal desert is a narrow lane along the Atlantic coast where the mist produced offshore by the cold Canary Currents provides enough moisture to maintain various moss, succulents, and shrubs. It covers an area of ​​39,900 square kilometers (15,400 sq mi) in southern Morocco and Mauritania.
The grasslands and grasslands of the northern Sahara are along the northern desert, alongside the Mediterranean forests, forests, and scrubs of ecoregions from the northern Maghreb and Cyrenaica. The winter rains support shrubs and dry forests that form a transition between the Mediterranean to the north and the hyper-arid Sahara just south. It covers 1,675,300 square kilometers (646,840 sqc, mi) in Algeria, Egypt, Libya, Mauritania, Morocco and Tunisia.
The Ecoregion Sahara desert covers the middle part of the Sahara hyper-arid where rainfall is minimal and sporadic. Vegetation is rare, and the ecoregion consists mostly of dunes (erg, chech, raoui), rock plains (hamadas), gravel plains ( reg >), dry valleys ( wadis ), and salt flats. It covers 4,639,900 square kilometers (1,791,500 sq., mi) from: Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, and Sudan.
The southern grasslands of the Sahara and forests ecoregion is a narrow band that runs east and west between the hyper-arid Sahara and the Sahel savanna in the south. The Equator Intertropical Convergence Zone (ITCZ) movement carries summer rains during July and August which average 100 to 200 mm (4 to 8 inches) but vary greatly from year to year. This rain sustains grasslands and summer herbs, with dry forests and shrubs along seasonal watercourses. The ecoregion includes 1,101,700 square kilometers (425,400 square meters) in Algeria, Chad, Mali, Mauritania and Sudan.
In jungle xeric forests of the Western Sahara , some highland volcanoes provide a colder and damper environment that supports the Saharo-Mediterranean forest and shrubs. The ecoregion includes 258,100 square kilometers (99,650 sq mi), mostly in Tassili n'Ajjer from Algeria, with smaller bags in AÃÆ'¯r from Niger, Dhar Adrar Mauritania, and Adrar des Iforas from Mali and Algeria.
The Tibesti-Jebel Uweinat montane xeric woodlands ecoregion consists of the Tibesti plateau and Jebel Uweinat. Higher and more regular rainfall and cooler temperatures support forests and shrubs of dates, acacia, myrtle, oleander, tamarix, and some rare and endemic plants. The ecoregion covers 82,200 square kilometers (31,700 sq mi) in Tibesti Chad and Libya, and Jebel Uweinat on the border of Egypt, Libya, and Sudan.
The Halophytics allowance is a seasonally flooded saline depression area that is home to a halophytic plant community (adapted from salt). The Saharan halophytics include 54,000 square kilometers (21,000 sq./a mi) including: Qattara and Shiva depression in northern Egypt, the Tunisian salt lake in central Tunisia, Chott Melghir in Algeria, and smaller areas of Algeria, Mauritania and the southern part of Morocco.
The Tanezrouft is one of the harshest regions on Earth as well as one of the hottest and driest parts of the Sahara, with no vegetation and very little life. It lies along the border of Algeria, Niger, and Mali, to the west of the Hoggar mountains.
Flora and fauna
Flora of the Sahara is highly diversified based on the bio-geographical characteristics of this vast desert. Interestingly, the Sahara has three zones based on the amount of rainfall received - the Northern Zone (Mediterranean), Central and South. There are two transition zones - the Mediterranean-Saharan transition and the Sahel transition zone.
The Sahara Flora consists of about 2800 species of vascular plants. About a quarter of this is endemic. About half of these species are common to Arabian desert flora.
Saharan is estimated to cover five hundred species of plants, which is very low given the vastness of the vast area. Plants such as acacia trees, palms, succulents, thorny bushes, and grasses have adapted to dry conditions, by growing lower to avoid water loss by strong winds, by storing water in their thick trunks to use it in dry periods, having a long root which runs horizontally to reach the maximum area of ​​water and to find surface moisture, and by having thick leaves or small needles to prevent water loss by evapotranspiration. Plant leaves can dry completely and then recover.
Some live fox species in the Sahara include: fennec fox, pale fox, and fox RÃÆ'¼ppell. Addax, the big white antelope, can go almost a year in the desert without a drink. Dorcas gazelle is a North African gazelle that can also be used for a long time without water. Other famous deer include rhim gazelle and dama gazelle.
The Sahara cheetah (northwest African cheetah) lives in Algeria, Togo, Niger, Mali, Benin, and Burkina Faso. Still less than 250 adult cheetahs, who are very cautious, escape from human existence. The cheetah avoids the sun from April to October, looking for shelter from bushes like balanites and acacias. They are incredibly pale. Other cheetah subspecies (the north-east African cheetah) live in Chad, Sudan and the eastern region of Niger. However, it is now extinct in the wild in Egypt and Libya. There are about 2000 adult individuals left in the wild.
Other animals include monitor lizards, hyrax, sand snakes, and small populations of African wild dogs, in perhaps only 14 countries and red ostriches. Other animals are in the Sahara (especially birds) such as African silver and black-faced firefinch, among others. There is also a small desert crocodile in Mauritania and the Ennedi Plateau in Chad.
The deathstalker scorpion can reach 10 cm (3.9 inches). Its toxins contain large amounts of agitoxin and scyllatoxin and are very dangerous; However, the sting of these scorpions rarely kills healthy adults. Saharan silver ants are unique because of the extreme high temperatures of their habitat, and the threat of predators, active ants outside their nests are only about ten minutes per day.
Camel and dromedary goats are the most common pets found in the Sahara. Due to the quality of durability and speed, dromedary is the favorite animal used by nomads.
Human activity is more likely to affect habitats in permanent water areas (oases) or where water is approaching the surface. Here, local pressure on natural resources can be very strong. The remaining large mammal populations have been greatly reduced by food and recreational hunting. In recent years development projects have begun in the deserts of Algeria and Tunisia using irrigated water pumped from underground aquifers. This scheme often leads to soil degradation and salinization.
Researchers from the Hacettepe University (YÃÆ'¼cluumlu, N. et al., 2011) have reported that the Sahara soil may have bio-available iron and also some important macro and micro nutrient elements suitable for use as fertilizer for growing wheat.
History
People lived on the edge of the desert thousands of years ago since the end of the last glacial period. The Sahara is a much wetter place than it is now. More than 30,000 petroglyphs of river animals such as crocodiles survive, with half found in Tassili n'Ajjer in southeastern Algeria. Dinosaur fossils, including Afrovenator , Jobaria and Ouranosaurus , have also been found here. Modern Sahara, though, is infertile in vegetation, except in the Nile Valley, in some oases, and in the northern highlands, where Mediterranean plants such as olive trees are found to grow. It has long been believed that this region has been like this since about 1600 BC, after a shift in the axis of the earth increases temperature and decreased rainfall, which caused a sudden descent of North Africa some 5,400 years ago. However, this theory has recently been debated, when samples taken from several 7-million-year-old sand deposits have led scientists to reconsider the timeline for desertification.
Kiffians
The Kiffian culture is a prehistoric industry, or domain, that existed between 10,000 and 8,000 years ago in the Sahara, during the Neolithic Subpluvial. Human remains of this culture were discovered in 2000 at a site known as Gobero, located in Niger in the TÃ © geher Desert. This site is known as the largest and earliest cemetery of the Stone Age people in the Sahara desert. The Kiffians are skilled hunters. The bones of many large savanna animals found in the same area show that they live on the shores of lakes that are present during the Holocene Wet Phase, the period when the Sahara is green and wet. The Kiffians were tall, more than six feet tall. The craniometric analysis shows that this early Holocene population was closely related to the Late Pleystocene Iberomaurus and the Early Holocene of the Maghreb, as well as the Mid-Holocene Mechta groups. The Kiffian cultural trail did not exist after 8,000 years ago, because the Sahara passed a dry period for the next thousand years. After this time, the Tenerian culture colonized the area.
Tenerian
Gobero was discovered in 2000 during an archaeological expedition led by Paul Sereno, who searched for the remains of dinosaurs. Two different prehistoric cultures are found on the site: early Holocene Kiffian culture, and Mediterranean mediterranean culture of the middle Holocene. The Kiffians were prehistoric people who preceded the people of Teneria and disappeared about 8000 years ago, when the deserts became very dry. The drying lasted until about 4600 BC, when the earliest artifacts associated with the people of Teneria had been dated. Approximately 200 skeletons have been found in Gobero. The Tenerians are much shorter and less powerful than the previous Kiffians. The craniometric analysis also shows that they are osteologically different. The Kiffian skull is similar to that of the Late Pleistocene Iberomaurian, early Holocene Capsians, and the central Mechta Holocene group, while the ternian crania is more similar to the Mediterranean group. The cemetery shows that the inhabitants of the Province observed the spiritual tradition, when they were buried with artifacts such as jewelry made of hippophe ivory and clay pots. The most interesting finding is that three times the burial, dating from 5300 years ago, from an adult woman and two children, estimated through their teeth at the age of five and eight, hugging each other. Pollen residues show that they are buried on a flower bed. All three are assumed to have died within 24 hours of each other, but because their skeleton does not experience a clear trauma (they do not die roughly) and they have been buried so complicated - it is impossible if they have died of the plague - their cause Death is a mystery.
Tashwinat Mummy
Uan Muhuggiag seems to have been inhabited since at least 6 millennia BC to about 2700 BC, though it does not have to be continuous. The most important finding in Uan Muhuggiag is a well preserved mummy from a boy about 2 1/2 years old. The child is in a fetal position, then embalmed, then placed in a sack made of antelope skin, which is isolated by a layer of leaves. The child's organs are removed, as evidenced by an incision in his abdomen and chest, and an organic preservative is inserted to stop his body from decay. The ostrich shell's necklace was also found on the neck. The radiocarbon dating determines the age of the mummy for about 5600 years, making it about 1000 years older than the earliest recorded mummy in ancient Egypt. In 1958-1959, an archaeological expedition led by Antonio Ascenzi undertook an anthropological, radiological, histological and chemical analysis on the mummified Uan Muhuggiag. The specimen was determined to be a 30-month-old child of an uncertain sex, which has the characteristics of a Negro. Long incisions on the abdominal wall of the specimen also indicate that the body was initially mummified by expenditure of the contents and then experienced a natural drought. One other individual, an adult, was found in Uan Muhuggiag, buried in a squatting position. However, the body does not show evidence of content expenditure or other preservation methods. The body is estimated to be from about 7500 BP.
Nubia
During the Neolithic Era, prior to the desertification around 9500 BC, Sudan was becoming a rich neighborhood that supported a large population that ranged in barren deserts, such as Wadi el-Qa'ab. In the 5th millennium BC, the people who inhabit what is now called Nubia, are full participants in the "agricultural revolution", living sedentary lifestyles with plants and pets. The art of cattle livestock and Saharan shepherds shows the existence of cattle cult as found in Sudan and other pastoral communities in Africa today. The Megalit found in Nabta Playa is a tangible example of perhaps the world's first archaeoastronomy device, which preceded Stonehenge for about 2,000 years. This complexity, as observed in Nabta Playa, and as expressed by various levels of authority within the community there, may form the basis for the structure of Neolithic society in Nabta and the Old Kingdom of Egypt.
Egypt
In the year 6000 BC, Egyptians living in Egypt's southwest Egypt were herding cattle and building large buildings. Subsistence in organized and permanent settlements in preclinical Egypt in the middle of the 6th millennium BC is centered mainly on cereals and animal agriculture: cattle, goats, pigs and sheep. Metal objects replaced previous stones. Animal tanning, earthenware and weaving are common in this era as well. There is an indication of seasonal or temporary occupation of Al Fayyum only in the 6th millennium BC, with food activities centered on fishing, hunting, and gathering food. Stone arrows, knives and scrapers of the times are usually found. Funerary items include pottery, jewelry, farming and hunting equipment, and a variety of foods including dried meat and fruits. The cemetery in the desert neighborhood seems to increase Egypt's preservation ceremony, and the dead are buried facing west.
In 3400 BC, the Sahara is as dry as it is today, due to reduced rainfall and higher temperatures due to Earth's orbit shift. As a result of this aridification, it becomes a very difficult barrier to be penetrated by humans, with the remaining settlements mainly concentrated around the various oases that stretches the landscape. Trade or small trades are known to have passed through the interior in the next period, the only exception being the Nile Valley. The Nile, however, is impassable in some cataracts, making trading and contact with boats difficult.
Phoenician
The Phenicians, who flourished from 1200-800 BC, created a royal confederation throughout the Sahara to Egypt. They commonly settle along the Mediterranean coast, as well as the Sahara, among the ancient Libyans, who are the ancestors of Berber-speaking people in North Africa and the Sahara today, including Tuareg from the central Sahara.
The Phoenician alphabet seems to have been adopted by the ancient Libyans of northern Africa, and Tifinagh is still in use today by Tuareg-speaking camel-speaking herders in the central Sahara.
Sometimes between 633 BC and 530 BC, Hanno the Navigator established or strengthened the Phoenician colonies in Western Sahara, but all the ancient remains have vanished with almost no trace.
Greek
In 500 BC, the Greeks arrived in the desert. Greek merchants spread along the east coast of the desert, building trade colonies along the Red Sea. The Carthaginians explored the Atlantic coast in the desert, but the turbulence of water and the lack of markets led to a lack of presence farther south than modern Moroccans. The centralized state thus circles the deserts of the north and east; it remains beyond the control of these countries. The raids of the nomadic Berber people in the desert are a constant concern for those living on the edge of the desert.
Civilization of the city
The civilization of the city, Garamantes, appeared around 500 BC in the heart of the Sahara, in a valley now called Wadi al-Ajal in Fezzan, Libya. The Garamantes achieved this development by digging tunnels deep into the mountains flanking the valley to tap the fossil water and bring it into their fields. The Garamantes grew densely populated and strong, conquered their neighbors and captured many slaves (who worked extending the tunnels). Ancient Greeks and Romans knew about Garamantes and regarded them as uncivilized nomads. However, they trade with them, and Roman baths have been found in the Garamantes capital Garama. Archaeologists have discovered eight major cities and many other important settlements in the Garamantes region. The Garamantes civilization finally collapsed after they depleted the water available in the aquifers and could no longer sustain efforts to expand the tunnel further into the mountains.
Berber
The Berber people occupy (and still occupy) most of the Sahara. The Garamantes Berbers built a prosperous empire in the heart of the desert. The nomadic Tuareg continue to inhabit and move across the vast surface of Sahara to this day.
Islamic Expansion
The Byzantine Empire ruled the northern shores of the Sahara from the 5th to 7th centuries. After the Muslim conquest of Arabia, especially the Arabian peninsula, Muslim conquests in North Africa began in the mid-7th century until the early 8th century and the influence of Islam developed rapidly in the Sahara. At the end of 641 all Egypt was in the hands of Muslims. Trading across the desert intensified, and significant slave trade across the desert. It is estimated that from the 10th to 19th centuries about 6,000 to 7,000 slaves were transported northward each year.
Ottoman-era Turkey
In the 16th century northern suburbs of the Sahara, such as the coastal districts of Algeria and Tunisia today, as well as some parts of Libya today, along with the semi-autonomous kingdom of Egypt, were occupied by the Ottoman Empire. From 1517 Egypt was a valuable part of the Ottoman Empire, an ownership that provided the Ottomans with control over the Nile Valley, the Eastern Mediterranean and North Africa. The benefits of the Ottoman Empire are freedom of movement for citizens and goods. Merchants exploit the Ottoman land routes to deal with spices, gold and silk from the East, manufactured goods from Europe, and slave and gold traffic from Africa. Arabic continues as local languages ​​and Islamic culture are strongly reinforced. The Sahel and the southern regions of the Sahara are home to several independent states or to explore the Tuareg clan.
European colonialism
European colonialism in the Sahara began in the 19th century. France conquered Algeria's District of the Ottomans in 1830, and the French government spread south from Algeria and east from Senegal to the upper Niger to include now Algeria, Chad, Mali, then French Sudan including Timbuktu, Mauritania, Morocco (1912), Niger , and Tunisia (1881). At the beginning of the 20th century, trans-Saharan trade had clearly declined as goods were moved through more modern and efficient means, such as airplanes, than across the desert.
The French Colonial Empire is the dominant presence in the Sahara. It established regular air connections from Toulouse (HQ of AÃÆ'  © ropostale), to Oran and passed Hoggar to Timbuktu and West to Bamako and Dakar, as well as trans-Saharan bus services run by La Companie Transsaharienne (est 1927). A remarkable film shot by famous aviator Captain Renà ©  © Wauthier documenting the first crossing by a large truck convoy from Algiers to Tchad, across the Sahara.
Egypt, under Muhammad Ali and his successors, conquered Nubia in 1820-22, founded Khartoum in 1823, and conquered Darfur in 1874. Egypt, including Sudan, became a British protectorate in 1882. Egypt and Britain lost control of Sudan from 1882 to 1898 as a result of the Mahdi War. After being captured by British troops in 1898, Sudan became an Anglo-Egyptian condominium.
Spain seized the current Western Sahara after 1874, although Rio del Oro remained largely under the influence of Sahrawi. In 1912, Italy took part of what Libya called from the Ottomans. To promote Roman Catholicism in the desert, Pope Pius IX appointed a messenger of Apostolic Sahara and Sudan in 1868; then in the nineteenth century its jurisdiction was reorganized into the Vicar Apostolic Vicariate.
Disconnect from the kingdom and thereafter
Egypt became independent from Britain in 1936, although the Anglo-Egyptian agreement of 1936 enabled the British to defend troops in Egypt and to defend British-Egyptian condominiums in Sudan. British military forces were withdrawn in 1954.
Most Saharan countries achieved independence after World War II: Libya in 1951; Morocco, Sudan and Tunisia in 1956; Chad, Mali, Mauritania, and Niger in 1960; and Algeria in 1962. Spain withdrew from the Western Sahara in 1975, and partitioned between Mauritania and Morocco. Mauritania resigned in 1979; Morocco continues to hold the territory.
In the post-World War II era, several mines and communities have grown to exploit desert natural resources. These include large deposits of oil and natural gas in Algeria and Libya, and large deposits of phosphates in Morocco and Western Sahara.
A number of Trans-African highways have been proposed throughout the Sahara, including the Cairo-Dakar Highway along the Atlantic coast, Trans-Sahara Highway from Algiers in the Mediterranean to Kano in Nigeria, Tripoli - Cape Town Highway from Tripoli in Libya to N'Djamena in Chad, and Cairo - Cape Town Highway which follows the Nile River. Each of these highways is partially complete, with significant gaps and unpaved sections.
People and languages ​​
The Sahara people come from various origins. Among them Amazi? including the Tour? q, the various Arabian Amazi? groups such as the Hassaniya-speaking Sahrawis, whose population includes Znaga, a tribe whose name is the remnant of prehistoric Zenaga. Other major groups include: Toubou, Nubia, Zaghawa, Kanuri, Hausa, Songhai, Beja, and Fula/Fulani (French: Peul ; Fula: Ful? E ).
Source of the article : Wikipedia
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