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87-666: In Africa, the Mousterian industry was an archaeological term for a category of Middle Stone Age (or Middle Paleolithic) stone tool production. During the time that archaeological dates were determined by radiocarbon decay, the production of such tools was once thought to have occurred just before the limit of radiocarbon dating at 40,000 to 35,000 BP. In Europe, Mousterian tools were made by archaic Neanderthals. In Africa, such tools were made by early anatomically-modern Homo sapiens . Similar people also made similar tools which are categorized as Alterian. To avoid confusion about their makers,

174-411: A bed of flowers. The three are assumed to have died within 24 hours of each other, but as their skeletons hold no apparent trauma (they did not die violently) and they have been buried so elaborately – unlikely if they had died of a plague – the cause of their deaths is a mystery. List of deserts by area List of the largest deserts in the world by area This

261-426: A consequence, the weather tends to be sunny, dry and stable with a minimal chance of rainfall. Subsiding, diverging, dry air masses associated with subtropical high-pressure systems are extremely unfavorable for the development of convectional showers. The subtropical ridge is the predominant factor that explains the hot desert climate ( Köppen climate classification BWh ) of this vast region. The descending airflow

348-519: A healthy adult. The Saharan silver ant is unique in that due to the extreme high temperatures of their habitat, and the threat of predators, the ants are active outside their nest for only about ten minutes per day. Dromedary camels and goats are the domesticated animals most commonly found in the Sahara. Because of its qualities of endurance and speed, the dromedary is the favourite animal used by nomads . Human activities are more likely to affect

435-569: A summer rainy season that extends across Africa from east to west. The southern limit of the Sahara is indicated botanically by the southern limit of Cornulaca monacantha (a drought-tolerant member of the Chenopodiaceae ), or northern limit of Cenchrus biflorus , a grass typical of the Sahel. According to climatic criteria, the southern limit of the Sahara corresponds to the 150 mm (5.9 in) isohyet of annual precipitation (this

522-542: A surface feature of Earth, with near-current technology. The Sahara is mainly rocky hamada (stone plateaus); ergs (sand seas – large areas covered with sand dunes ) form only a minor part, contrary to common misconception , but many of the sand dunes are over 180 metres (590 ft) high. Wind or rare rainfall shape the desert features: sand dunes, dune fields, sand seas, stone plateaus, gravel plains ( reg ), dry valleys ( wadi ), dry lakes ( oued ), and salt flats ( shatt or chott ). Unusual landforms include

609-610: A “Mousterian Pluvial.” They are not associated with strong “Green Sahara” events, like the ones of the Eemian in early MIS 5; the late MIS 5 humid period (105,000 to 75 BP); or the early Holocene. Few if any Mousterian or Aterian toolmakers survived in North Africa to witness them. Some older descriptions of the Mousterian Pluvial described it as a strong African Humid period. During earlier strong African Humid periods,

696-1136: Is a list of the largest deserts in the world by area. It includes all deserts above 50,000 km (19,300 sq mi). [REDACTED] Some of Earth 's biggest non-polar deserts Rank Name Type Image Area (km ) Area (sq mi) Location Nation(s) 1 Antarctic Desert Polar ice and tundra [REDACTED] 14,200,000,000,000,000 14,200,000 05,482,651 5,482,651 Antarctica N/A 2 Arctic Desert Polar ice and tundra [REDACTED] 13,900,000 13,900,000 05,366,820 5,366,820 Eastern Europe Northern America Northern Asia Northern Europe Alaska ( United States ), Canada ( Yukon , Nunavut and Northwest Territories ), Finland , Greenland , Iceland , Svalbard and Jan Mayen ( Norway ), Siberia ( Russia ), and Sweden 3 Saharan Desert Subtropical [REDACTED] 09,200,000 9,200,000 03,552,140 3,552,140 Eastern Africa Middle Africa Northern Africa Western Africa Algeria , Chad , Egypt , Eritrea , Libya , Mali , Mauritania , Morocco ,

783-660: Is a long-term average, since precipitation varies annually). Important cities located in the Sahara include Nouakchott , the capital of Mauritania; Tamanrasset , Ouargla , Béchar , Hassi Messaoud , Ghardaïa , and El Oued in Algeria; Timbuktu in Mali; Agadez in Niger; Ghat in Libya; and Faya-Largeau in Chad. The Sahara is the world's largest hot desert . It is located in

870-422: Is a north African gazelle that can also go for a long time without water. Other notable gazelles include the rhim gazelle and dama gazelle . The Saharan cheetah ( northwest African cheetah ) lives in Algeria, Togo , Niger, Mali, Benin , and Burkina Faso . There remain fewer than 250 mature cheetahs, which are very cautious, fleeing any human presence. The cheetah avoids the sun from April to October, seeking

957-629: 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 from this culture were found in 2000 at a site known as Gobero , located in Niger in the Ténéré Desert . The site is known as the largest and earliest grave of Stone Age people in the Sahara. The Kiffians were skilled hunters . Bones of many large savannah animals that were discovered in

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1044-465: Is associated with high rates of wind-blown mineral dust, and these dust levels are found as expected in marine cores from the north tropical Atlantic. But around 12,500 BCE the amount of dust in the cores in the Bølling / Allerød phase suddenly plummets and shows a period of much wetter conditions in the Sahara, indicating a Dansgaard-Oeschger (DO) event (a sudden warming followed by a slower cooling of

1131-403: Is estimated to include five hundred species of plants, which is extremely low considering the huge extent of the area. Plants such as acacia trees, palms, succulents, spiny shrubs, and grasses have adapted to the arid conditions, by growing lower to avoid water loss by strong winds, by storing water in their thick stems to use it in dry periods, by having long roots that travel horizontally to reach

1218-407: Is the largest hot desert in the world and the third-largest desert overall, smaller only than the deserts of Antarctica and the northern Arctic . The name "Sahara" is derived from Arabic : صَحَارَى , romanized :  ṣaḥārā /sˤaħaːraː/ , a broken plural form of ṣaḥrā' ( صَحْرَاء /sˤaħraːʔ/ ), meaning "desert". The desert covers much of North Africa , excluding

1305-667: Is the strongest and the most effective over the eastern part of the Great Desert, in the Libyan Desert: this is the sunniest, driest and the most nearly "rainless" place on the planet, rivaling the Atacama Desert , lying in Chile and Peru . The rainfall inhibition and the dissipation of cloud cover are most accentuated over the eastern section of the Sahara rather than the western. The prevailing air mass lying above

1392-422: Is very unreliable and erratic in the Sahara as it may vary considerably year by year. In full contrast to the negligible annual rainfall amounts, the annual rates of potential evaporation are extraordinarily high, roughly ranging from 2,500 millimetres (100 in) per year to more than 6,000 millimetres (240 in) per year in the whole desert. Nowhere else on Earth has air been found as dry and evaporative as in

1479-543: The Adrar of Mauritania and a value of 75 °C (167 °F) has been measured in Borkou , northern Chad. Due to lack of cloud cover and very low humidity, the desert usually has high diurnal temperature variations between days and nights. However, it is a myth that the nights are especially cold after extremely hot days in the Sahara. On average, nighttime temperatures tend to be 13–20 °C (23–36 °F) cooler than in

1566-488: The Algerian Desert called Bou Bernous , at an elevation of 378 metres (1,240 ft) above sea level, and only Death Valley, California rivals it. Other hot spots in Algeria such as Adrar , Timimoun , In Salah , Ouallene , Aoulef , Reggane with an elevation between 200 and 400 metres (660 and 1,310 ft) above sea level get slightly lower summer average highs, around 46 °C (114.8 °F) during

1653-765: The Late Pleistocene Iberomaurusians , early Holocene Capsians , and mid-Holocene Mechta groups, whereas the Tenerian crania are more like those of Mediterranean groups. Graves show that the Tenerians observed spiritual traditions, as they were buried with artifacts such as jewelry made of hippo tusks and clay pots. The most interesting find is a triple burial, dated to 5300 years ago, of an adult female and two children, estimated through their teeth as being five and eight years old, hugging each other. Pollen residue indicates they were buried on

1740-1666: The Niger , the Sudan , Tunisia , and Western Sahara 4 Arabian Desert Subtropical [REDACTED] 02,330,000 2,330,000 00,899,618 899,618 Western Asia Iraq , Jordan , Kuwait , Oman , Qatar , Saudi Arabia , the United Arab Emirates , and Yemen 5 Great Australian Desert Subtropical [REDACTED] 01,371,000 1,371,000 00,529,346 529,346 Australasia Australia 6 Gobi Desert Cold winter [REDACTED] 01,295,000 1,295,000 00,500,002 500,002 Eastern Asia China and Mongolia 7 Kalahari Desert Subtropical [REDACTED] 00,900,000 900,000 00,347,492 347,492 Southern Africa Botswana , Namibia , and South Africa 8 Patagonian Desert Cold winter [REDACTED] 00,673,000 673,000 00,259,847 259,847 South America Argentina and Chile 9 Syrian Desert Subtropical [REDACTED] 00,500,000 500,000 00,193,051 193,051 Western Asia Iraq , Jordan , Saudi Arabia , and Syria 10 Great Basin Desert Cold winter [REDACTED] 00,492,098 492,098 00,190,000 190,000 Northern America Nevada , Utah , California and Idaho ( United States ) 11 Chihuahuan Desert Subtropical [REDACTED] 00,453,248 453,248 00,175,000 175,000 Central America Northern America Mexico and

1827-711: The Niger River valley and the Sudan region of sub-Saharan Africa . The Sahara can be divided into several regions, including the western Sahara, the central Ahaggar Mountains , the Tibesti Mountains , the Aïr Mountains , the Ténéré desert, and the Libyan Desert . For several hundred thousand years, the Sahara has alternated between desert and savanna grassland in a 20,000-year cycle caused by

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1914-694: The Richat Structure in Mauritania. Several deeply dissected mountains, many volcanic, rise from the desert, including the Aïr Mountains , Ahaggar Mountains , Saharan Atlas , Tibesti Mountains , Adrar des Iforas , and the Red Sea Hills . The highest peak in the Sahara is Emi Koussi , a shield volcano in the Tibesti range of northern Chad. The central Sahara is hyperarid , with sparse vegetation. The northern and southern reaches of

2001-540: The United Nations geoscheme . ^ A part of the Great Australian Desert . See also [ edit ] Desert Desertification List of deserts by continent Polar desert Tundra United Nations Convention to Combat Desertification References [ edit ] ^ "Top ten largest (non-polar) deserts" . Archived from

2088-843: The United States 12 Karakum Desert Cold winter [REDACTED] 00,350,000 350,000 00,135,136 135,136 Central Asia Turkmenistan – Great Victoria Desert Subtropical [REDACTED] 00,348,750 348,750 00,134,653 134,653 Australasia Australia 13 Taklamakan Desert Cold winter [REDACTED] 00,270,000 337,000 00,104,248 130,191 Eastern Asia China 14 Colorado Plateau Cold winter [REDACTED] 00,337,000 336,700 00,130,116 130,116 Northern America United States 15 Sonoran Desert Subtropical [REDACTED] 00,310,000 310,000 00,119,692 119,692 Central America Northern America Mexico and

2175-2274: The United States 16 Kyzylkum Desert Cold winter [REDACTED] 00,300,000 300,000 00,115,831 115,831 Central Asia Kazakhstan , Turkmenistan , and Uzbekistan 17 Ogaden Desert Subtropical [REDACTED] 00,256,000 256,000 00,098,842 98,842 Eastern Africa Ethiopia , Somalia , and Somaliland 18 Thar Desert Subtropical [REDACTED] 238,254 00,077,220 77,220 Southern Asia India and Pakistan 19 Puntland Desert Subtropical [REDACTED] 00,200,000 200,000 00,077,220 77,220 Eastern Africa Somalia 20 Ustyurt Plateau Temperate [REDACTED] 00,200,000 200,000 00,077,220 77,220 Central Asia Kazakhstan , Turkmenistan , and Uzbekistan 21 Guban Desert Subtropical [REDACTED] 00,175,000 175,000 00,067,568 67,568 Eastern Africa Somalia / Somaliland 22 Namib Desert Cool coastal [REDACTED] 00,160,000 160,000 00,061,776 61,776 Middle Africa Southern Africa Angola , Namibia , and South Africa 23 Margo Desert Subtropical [REDACTED] 00,150,000 150,000 00,057,915 57,915 Southern Asia Afghanistan 24 Registan Desert Subtropical [REDACTED] 00,146,000 146,000 00,056,371 56,371 Southern Asia Afghanistan 25 Atacama Desert Mild coastal [REDACTED] 00,140,000 140,000 00,054,054 54,054 South America Chile and Peru 26 Danakil Desert Subtropical [REDACTED] 00,137,000 137,000 00,052,896 52,896 Eastern Africa Djibouti , Eritrea , and Ethiopia 27 Mojave Desert Subtropical [REDACTED] 00,124,000 124,000 00,047,877 47,877 Northern America United States 28 Chalbi Desert Subtropical [REDACTED] 00,100,000 100,000 00,038,610 38,610 Eastern Africa Kenya 29 Columbia Basin Cold winter [REDACTED] 00,083,139 83,139 00,032,100 32,100 Northern America Canada and

2262-618: The United States 30 Kavir Desert Subtropical [REDACTED] 00,077,000 77,000 00,029,730 29,730 Southern Asia Iran 31 Ferlo Desert Subtropical [REDACTED] 00,070,000 70,000 00,027,027 27,027 Western Africa Senegal 32 Ladakh Desert Cold winter [REDACTED] 00,059,146 59,146 00,022,836 22,836 Southern Asia India 33 Lut Desert Subtropical [REDACTED] 00,052,000 52,000 00,020,077 20,077 Southern Asia Iran Notes [ edit ] ^ As per

2349-474: The horse latitudes under the subtropical ridge , a significant belt of semi-permanent subtropical warm-core high pressure where the air from the upper troposphere usually descends, warming and drying the lower troposphere and preventing cloud formation. The permanent absence of clouds allows unhindered light and thermal radiation. The stability of the atmosphere above the desert prevents any convective overturning, thus making rainfall virtually non-existent. As

2436-533: The jet stream passing over North America. The jet stream effectively split into two, which created a new dominant weather pattern over the northern hemisphere that brought harsher conditions to several regions (including parts of Central Asia and the Middle East ). The changes included an end to the Mousterian Pluvial and a return to a more arid climate in Northern Africa. It is now understood that

2523-514: The precession of Earth's axis (about 26,000 years) as it rotates around the Sun, which changes the location of the North African monsoon . The Sahara covers large parts of Algeria , Chad , Egypt , Libya , Mali , Mauritania , Niger , Western Sahara and Sudan , and parts of southern Morocco and Tunisia . It covers 9 million square kilometres (3,500,000 sq mi), 31% of

2610-509: The African continent. If all areas with a mean annual precipitation of less than 250 mm (9.8 in) were included, the Sahara would be 11 million square kilometres (4,200,000 sq mi). It is one of three distinct physiographic provinces of the African massive physiographic division . The Sahara is so large and bright that, in theory, it could be detected from other stars as

2697-417: The African humid period. At its largest extent, sometime before 5000 BCE, Lake Mega-Chad was the largest of four Saharan paleolakes, and is estimated to have covered an area of 350,000 km . The Sahara pump theory describes this cycle. During periods of a wet or " Green Sahara ", the Sahara becomes a savanna grassland and various flora and fauna become more common. Following inter-pluvial arid periods,

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2784-412: The Great Desert the hottest large region in the world, and the hottest place on Earth during summer in some spots. The average high temperature exceeds 38 to 40 °C (100.4 to 104.0 °F) during the hottest month nearly everywhere in the desert except at very high altitudes. The world's highest officially recorded average daily high temperature was 47 °C (116.6 °F) in a remote desert town in

2871-486: The Intertropical Convergence Zone from the south and the annual average rainfall ranges from 100 millimetres (4 in) to 250 millimetres (10 in). For example, Timbuktu, Mali and Agadez , Niger are found in this zone. The vast central hyper-arid core of the desert is virtually never affected by northerly or southerly atmospheric disturbances and permanently remains under the influence of

2958-523: The Kiffian culture do not exist after 8,000 years ago, as the Sahara went through a dry period for the next thousand years. After this time, the Tenerian culture colonized the area. Gobero was discovered in 2000 during an archaeological expedition led by Paul Sereno , which sought dinosaur remains. Two distinct prehistoric cultures were discovered at the site: the early Holocene Kiffian culture, and

3045-733: The Mojave Desert" (PDF) . pubs.usgs.gov . USGS Western Geographic Science Center. 2011-06-01. Archived (PDF) from the original on 2013-05-09 . Retrieved 2012-04-08 . ^ "Recoverability and Vulnerability of Desert Ecosystems" . mojave.usgs.gov . USGS. 2006-03-03. Archived from the original on 2012-05-01 . Retrieved 2012-04-14 . ^ Wright, John W., ed. (2006). The New York Times Almanac (2007 ed.). New York, New York: Penguin Books. p.  456 . ISBN   0-14-303820-6 . ^ "The Cold Desert – Ladakh" . 6 March 2018. Archived from

3132-646: The Mousterian and Alterian tools are now sometimes grouped as Aterian. With more recent dating methods, the tools are now understood to have been mostly produced during the humid Eemian interglacial and later phases of MIS 5, from 130,000 to 72,000 BP. Mousterian tools are frequently older than the Aterian tools. During the dry period that followed in Northern Africa, from 71,000 to 14,500 BP, recent research has found that there were 3 semi-humid interruptions: 65,000 to 61,000 BP, 52,500 to 50,500 BP, and 37,500 to 33,000 BP. The last two have sometimes been grouped to constitute

3219-462: The Sahara (birds in particular) such as African silverbill and black-faced firefinch , among others. There are also small desert crocodiles in Mauritania and the Ennedi Plateau of Chad. The deathstalker scorpion can be 10 cm (3.9 in) long. Its venom contains large amounts of agitoxin and scyllatoxin and is very dangerous; however, a sting from this scorpion rarely kills

3306-531: The Sahara area then reverts to desert conditions and the flora and fauna are forced to retreat northwards to the Atlas Mountains , southwards into West Africa , or eastwards into the Nile Valley . This separates populations of some of the species in areas with different climates , forcing them to adapt , possibly giving rise to allopatric speciation . It is also proposed that humans accelerated

3393-528: The Sahara is strongly influenced by the North Atlantic Oscillation (NAO), with warmer winter temperatures during negative NAO events and cooler winters with more frosts when the NAO is positive. This is because the weaker clockwise flow around the eastern side of the subtropical anticyclone during negative NAO winters, although too dry to produce more than negligible precipitation, does reduce

3480-504: The Sahara is the continental tropical (cT) air mass, which is hot and dry. Hot, dry air masses primarily form over the North-African desert from the heating of the vast continental land area, and it affects the whole desert during most of the year. Because of this extreme heating process, a thermal low is usually noticed near the surface, and is the strongest and the most developed during the summertime. The Sahara High represents

3567-573: The Sahara region. However, at least two instances of snowfall have been recorded in Sahara, in February 1979 and December 2016, both in the town of Ain Sefra . One theory for the formation of the Sahara is that the monsoon in Northern Africa was weakened because of glaciation during the Quaternary period, starting two or three million years ago. Another theory is that the monsoon was weakened when

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3654-713: The Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs , including Afrovenator , Jobaria and Ouranosaurus , have also been found here. The modern Sahara, though, is not lush in vegetation, except in the Nile Valley, at a few oases , and in the northern highlands, where Mediterranean plants such as the olive tree are found to grow. Shifts in Earth's axis increased temperatures and decreased precipitation, which caused an abrupt beginning of North Africa desertification about 5,400 years ago. The Kiffian culture

3741-595: The amount of rainfall received – the Northern (Mediterranean), Central and Southern Zones. There are two transitional zones – the Mediterranean-Sahara transition and the Sahel transition zone. The Saharan flora comprises around 2800 species of vascular plants . Approximately a quarter of these are endemic . About half of these species are common to the flora of the Arabian deserts. The central Sahara

3828-550: The ancient Tethys Sea dried up during the Tortonian period around 7 million years ago. The climate of the Sahara has undergone enormous variations 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 alters the path of the North African Monsoon – usually southward. The cycle is caused by a 41,000-year cycle in which

3915-421: The atmospheric circulation itself, the desert is made even drier by its geographical configuration and location. Indeed, the extreme aridity of the Sahara is not only explained by the subtropical high pressure: the Atlas Mountains of Algeria, Morocco and Tunisia also help to enhance the aridity of the northern part of the desert. These major mountain ranges act as a barrier, causing a strong rain shadow effect on

4002-616: The climate). The moister Saharan conditions had begun about 12,500 BCE, with the extension of the ITCZ northward in the northern hemisphere summer, bringing moist wet conditions and a savanna climate to the Sahara, which (apart from a short dry spell associated with the Younger Dryas ) peaked during the Holocene thermal maximum climatic phase at 4000 BCE when mid-latitude temperatures seem to have been between 2 and 3 degrees warmer than in

4089-474: The daytime. The smallest variations are found along the coastal regions due to high humidity and are often even lower than a 10 °C (18 °F) difference, while the largest variations are found in inland desert areas where the humidity is the lowest, mainly in the southern Sahara. Still, it is true that winter nights can be cold, as it can drop to the freezing point and even below, especially in high-elevation areas. The frequency of subfreezing winter nights in

4176-469: The desert experiences around three to five months when the average high strictly exceeds 40 °C (104 °F); while in the southern central part of the desert, there are up to six or seven months when the average high temperature strictly exceeds 40 °C (104 °F). Some examples of this are Bilma , Niger and Faya-Largeau, Chad. The annual average daily temperature exceeds 20 °C (68 °F) everywhere and can approach 30 °C (86 °F) in

4263-530: The desert, along with the highlands, have areas of sparse grassland and desert shrub , with trees and taller shrubs in wadis , where moisture collects. In the central, hyperarid region, there are many subdivisions of the great desert: Tanezrouft , the Ténéré , the Libyan Desert , the Eastern Desert , the Nubian Desert and others. These extremely arid areas often receive no rain for years. To

4350-531: The drying-out period from 6000 to 2500 BCE by pastoralists overgrazing available grassland. The growth of speleothems (which requires rainwater) was detected in Hol-Zakh, Ashalim , Even-Sid, Ma'ale-ha-Meyshar, Ktora Cracks, Nagev Tzavoa Cave, and elsewhere, and has allowed tracking of prehistoric rainfall. The Red Sea coastal route was extremely arid before 140 and after 115 kya (thousands of years ago). Slightly wetter conditions appear at 90–87 kya, but it still

4437-632: The earlier Eemian humid period. The old theory was that the Mousterian Pluvial was caused by large-scale climatic changes during the last ice age . By 50,000 BP, the Wisconsin glaciation ("Würm glaciation" in Europe) was well-advanced. Growing ice sheets in North America and Europe displaced the standard climatic zones of the northern hemisphere southward. The temperate zones of Europe and North America acquired an Arctic or tundra climate, and

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4524-667: The eastern continental extension of the Azores High , centered over the North Atlantic Ocean . The subsidence of the Sahara High nearly reaches the ground during the coolest part of the year, while it is confined to the upper troposphere during the hottest periods. The effects of local surface low pressure are extremely limited because upper-level subsidence still continues to block any form of air ascent. Also, to be protected against rain-bearing weather systems by

4611-614: The edge of the desert thousands of years ago, since the end of the last glacial period . In the Central Sahara, engraved and painted rock art were created perhaps as early as 10,000 years ago, spanning the Bubaline Period , Kel Essuf Period , Round Head Period , Pastoral Period , Caballine Period , and Cameline Period . The Sahara was then a much wetter place than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive, with half found in

4698-822: The fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb , and the Nile Valley in Egypt and the Sudan . It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains. To the south it is bounded by the Sahel , a belt of semi-arid tropical savanna around

4785-484: The flow of dry, cold air from higher latitudes of Eurasia into the Sahara significantly. The average annual rainfall ranges from very low in the northern and southern fringes of the desert to nearly non-existent over the central and the eastern part. The thin northern fringe of the desert receives more winter cloudiness and rainfall due to the arrival of low pressure systems over the Mediterranean Sea along

4872-699: The habitat in areas of permanent water (oases) or where water comes close to the surface. Here, the local pressure on natural resources can be intense. The remaining populations of large mammals have been greatly reduced by hunting for food and recreation. In recent years development projects have started in the deserts of Algeria and Tunisia using irrigated water pumped from underground aquifers. These schemes often lead to soil degradation and salinization . Researchers from Hacettepe University have reported that Saharan soil may have bio-available iron and also some essential macro and micro nutrient elements suitable for use as fertilizer for growing wheat. People lived on

4959-405: The highest recorded worldwide. The sky is usually clear above the desert, and the sunshine duration is extremely high everywhere in the Sahara. Most of the desert has more than 3,600 hours of bright sunshine per year (over 82% of daylight hours), and a wide area in the eastern part has over 4,000 hours of bright sunshine per year (over 91% of daylight hours). The highest values are very close to

5046-551: The hottest months of the year. Salah, well known in Algeria for its extreme heat, has average high temperatures of 43.8 °C (110.8 °F), 46.4 °C (115.5 °F), 45.5 °C (113.9 °F) and 41.9 °C (107.4 °F) in June, July, August and September respectively. There are even hotter spots in the Sahara, but they are located in extremely remote areas, especially in the Azalai , lying in northern Mali. The major part of

5133-491: The hottest regions year-round. However, most of the desert has a value in excess of 25 °C (77 °F). Sand and ground temperatures are even more extreme. During daytime, the sand temperature is extremely high: it can easily reach 80 °C (176 °F) or more. A sand temperature of 83.5 °C (182.3 °F) has been recorded in Port Sudan . Ground temperatures of 72 °C (161.6 °F) have been recorded in

5220-406: The last glacial period , the Sahara was much larger than it is today, extending south beyond its current boundaries. The end of the glacial period brought more rain to the Sahara, from about 8000 BCE to 6000 BCE, perhaps because of low pressure areas over the collapsing ice sheets to the north. Once the ice sheets were gone, the northern Sahara dried out. In the southern Sahara, the drying trend

5307-458: The late nineteenth century, The hypothesis was later formally proposed and tested by the meteorologist John Kutzbach in 1981. Kutzbach's ideas about the impacts of insolation on global monsoonal patterns have become widely accepted today as the underlying driver of long-term monsoonal cycles. Kutzbach never formally named his hypothesis and as such it is referred to here as the " Orbital Monsoon Hypothesis " as suggested by Ruddiman in 2001. During

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5394-530: The leeward side by dropping much of the humidity brought by atmospheric disturbances along the polar front which affects the surrounding Mediterranean climates. The primary source of rain in the Sahara is the Intertropical Convergence Zone , a continuous belt of low-pressure systems near the equator which bring the brief, short and irregular rainy season to the Sahel and southern Sahara. Rainfall in this giant desert has to overcome

5481-493: The major African humid period events were caused by increased insolation in the northern hemisphere and the impact of continental surface warming on the tropical monsoons. This article about atmospheric science is a stub . You can help Misplaced Pages by expanding it . Sahara Desert The Sahara ( / s ə ˈ h ɑːr ə / , / s ə ˈ h ær ə / ) is a desert spanning across North Africa . With an area of 9,200,000 square kilometres (3,600,000 sq mi), it

5568-419: The maximum area of water and to find any surface moisture, and by having small thick leaves or needles to prevent water loss by evapotranspiration . Plant leaves may dry out totally and then recover. Several species of fox live in the Sahara including: the fennec fox , pale fox and Rüppell's fox . The addax , a large white antelope , can go nearly a year in the desert without drinking. The dorcas gazelle

5655-437: The middle Holocene Tenerian culture . The post-Kiffian desiccation lasted until around 4600 BCE, when the earliest artefacts associated with the Tenerians have been dated to. Some 200 skeletons have been discovered at Gobero. The Tenerians were considerably shorter in height and less robust than the earlier Kiffians. Craniometric analysis also indicates that they were osteologically distinct. The Kiffian skulls are akin to those of

5742-579: The north, the Sahara skirts the Mediterranean Sea in Egypt and portions of Libya, but in Cyrenaica and the Maghreb , the Sahara borders the Mediterranean forest, woodland, and scrub eco-regions of northern Africa, all of which have a Mediterranean climate characterized by hot summers and cool and rainy winters. According to the botanical criteria of Frank White and geographer Robert Capot-Rey,

5829-422: The northern limit of the Sahara corresponds to the northern limit of date palm cultivation and the southern limit of the range of esparto , a grass typical of the Mediterranean climate portion of the Maghreb and Iberia . The northern limit also corresponds to the 100 mm (3.9 in) isohyet of annual precipitation. To the south, the Sahara is bounded by the Sahel, a belt of dry tropical savanna with

5916-508: The now-desiccated regions of northern Africa were well-watered, bearing lakes, swamps, and river systems that no longer exist. What is now the Sahara Desert supported typical African wildlife of grassland and woodland environments: herbivores from gazelle to giraffe to ostrich , predators from lion to jackal , even hippopotamus and crocodile , as well as extinct forms like the Pleistocene camel . The humid periods of 52,500 to 50,000 BP and 37,5000 to 33,000 were not as strong as those of

6003-407: The opposite is true, with decreased annual precipitation and less vegetation resulting in a phase of the Sahara climate cycle known as the "desert Sahara". The idea that changes in insolation (solar heating) caused by long-term changes in Earth's orbit are a controlling factor for the long-term variations in the strength of monsoon patterns across the globe was first suggested by Rudolf Spitaler in

6090-459: The original on 2012-07-10 . Retrieved 2012-04-26 . ^ "Largest Desert in the World" . Archived from the original on 2007-08-17 . Retrieved 2021-05-14 . ^ "Thar Desert | Map, Climate, Vegetation, & Facts" . Encyclopedia Britannica . 24 May 2023. Archived from the original on 20 June 2008 . Retrieved 19 February 2021 . ^ "Mapping Perennial Vegetation Cover in

6177-432: The original on 2021-01-26 . Retrieved 2021-05-14 . ^ "Arabian Desert" . Archived from the original on 2007-12-31 . Retrieved 2007-12-28 . ^ Areas of Australian and territory deserts by Geoscience Australia ^ Bass, Karen (2009-02-01). "Nature's Great Events:The Okavango Delta, Kalahari Desert" (PDF) . press.uchicago.edu . University of Chicago Press. Archived (PDF) from

6264-3659: The original on 2021-10-17 . Retrieved 2021-10-17 . v t e World deserts Desert Desertification Polar desert List of deserts List of deserts by area Desert exploration Africa Algerian Bayuda Black Desert Blue Chalbi Danakil Djurab Eastern Ferlo Farafra (White) Kalahari Libyan Moçâmedes Namib Nubian Nyiri Plaine des Sables Richtersveld Sahara Tanezrouft Ténéré Western Asia Arabian Peninsula Ad-Dahna Nefud Arabian Judaean Negev Ramlat al-Sab'atayn Rub' al Khali Syrian Wahiba Sands Central Asia Aral Karakum Aralkum Barsuki Betpak-Dala Dasht-e Naomid Karakum Kyzylkum Moiynkum Ryn Saryesik-Atyrau Sarykum Taukum Ustyurt East Asia Badain Jaran Gobi Gurbantünggüt Hami Lop Kumtag Ordos Kubuqi Mu Us Qaidam Taklamakan Tengger South Asia Cholistan Indus Valley Katpana Kharan Thal Thar Iranian plateau Kavir Khash Leili Lut Margo Naomid Polond Registan Southeast Asia La Paz Europe Bardenas Reales Cabo de Gata Monegros Oleshky Tabernas Deliblato North America Alvord Amargosa Baja California Black Rock Carcross Carson Channeled scablands Chihuahuan Colorado Escalante Forty Mile Gran Desierto de Altar Great Basin Great Salt Lake Great Sandy Jornada del Muerto Kaʻū Lechuguilla Mojave North American Arctic Owyhee Painted Desert Red Desert Sevier Smoke Creek Sonoran Tonopah Desert Tule (Arizona) Tule (Nevada) Yuha Yuma Oceania Australia Gibson Great Sandy Great Victoria Little Sandy Nullarbor Plain Painted Pedirka Simpson Strzelecki Sturt Stony Tanami Tirari New Zealand Rangipo South America Atacama La Guajira Los Médanos de Coro Monte Patagonian Sechura Tatacoa Polar regions Antarctic Antarctica Meyer Desert Arctic North American Arctic Greenland Russian Arctic Project Category Commons Retrieved from " https://en.wikipedia.org/w/index.php?title=List_of_deserts_by_area&oldid=1258419013 " Categories : Lists of landforms Deserts Geology-related lists Deserts and xeric shrublands Lists by area Lists of deserts Hidden categories: Articles with short description Short description

6351-419: The physical and atmospheric barriers that normally prevent the production of precipitation. The harsh climate of the Sahara is characterized by: extremely low, unreliable, highly erratic rainfall; extremely high sunshine duration values; high temperatures year-round; negligible rates of relative humidity ; a significant diurnal temperature variation ; and extremely high levels of potential evaporation which are

6438-401: The polar front, although very attenuated by the rain shadow effects of the mountains and the annual average rainfall ranges from 100 millimetres (4 in) to 250 millimetres (10 in). For example, Biskra , Algeria, and Ouarzazate , Morocco, are found in this zone. The southern fringe of the desert along the border with the Sahel receives summer cloudiness and rainfall due to the arrival of

6525-527: The rain bands typical of the temperate zones dropped to the latitudes of northern Africa. Curiously, the same influences that created the Mousterian Pluvial were thought to have brought it to a close. In the period of its fullest development from 30,000 to 18,000 BP, the Laurentide Ice Sheet not only covered an enormous geographic area but also increased its altitude to 1750 m (1.1 mi). It generated its own long-term weather patterns, which affected

6612-532: The recent past. Analysis of Nile River deposited sediments in the delta also shows this period had a higher proportion of sediments coming from the Blue Nile , suggesting higher rainfall also in the Ethiopian Highlands . This was caused principally by a stronger monsoonal circulation throughout the sub-tropical regions, affecting India, Arabia and the Sahara. Lake Victoria only recently became

6699-663: The same area suggest that they lived on the shores of a lake that was present during the Holocene Wet Phase, a period when the Sahara was verdant and wet. The Kiffian people were tall, standing over six feet in height. Craniometric analysis indicates that this early Holocene population was closely related to the Late Pleistocene Iberomaurusians and early Holocene Capsians of the Maghreb, as well as mid-Holocene Mechta groups. Traces of

6786-463: The scale of the Nile floods between 2700 and 2100 BCE. The Sahara comprises several distinct ecoregions . With their variations in temperature, rainfall, elevation, and soil, these regions harbor distinct communities of plants and animals. The flora of the Sahara is highly diversified based on the bio-geographical characteristics of this vast desert. Floristically , the Sahara has three zones based on

6873-521: The shelter of shrubs such as balanites and acacias. They are unusually pale. The other cheetah subspecies ( northeast African cheetah ) lives in Chad, Sudan and the eastern region of Niger. However, it is currently extinct in the wild in Egypt and Libya. There are approximately 2000 mature individuals left in the wild. Other animals include the monitor lizards , hyrax , sand vipers , and small populations of African wild dog , in perhaps only 14 countries and red-necked ostrich . Other animals exist in

6960-596: The source of the White Nile and dried out almost completely around 15 kya. The sudden subsequent movement of the ITCZ southwards with a Heinrich event (a sudden cooling followed by a slower warming), linked to changes with the El Niño-Southern Oscillation cycle, led to a rapid drying out of the Saharan and Arabian regions, which quickly became desert. This is linked to a marked decline in

7047-561: The strongest anticyclonic weather regime, and the annual average rainfall can drop to less than 1 millimetre (0.04 in). In fact, most of the Sahara receives less than 20 millimetres (0.8 in). Of the 9,000,000 square kilometres (3,500,000 sq mi) of desert land in the Sahara, an area of about 2,800,000 square kilometres (1,100,000 sq mi) (about 31% of the total area) receives an annual average rainfall amount of 10 millimetres (0.4 in) or less, while some 1,500,000 square kilometres (580,000 sq mi) (about 17% of

7134-562: The theoretical maximum value. A value of 4300 hours (98%) of the time would be recorded in Upper Egypt ( Aswan , Luxor ) and in the Nubian Desert ( Wadi Halfa ). The annual average direct solar irradiation is around 2,800 kWh/(m year) in the Great Desert. The Sahara has a huge potential for solar energy production. The high position of the Sun, the extremely low relative humidity, and the lack of vegetation and rainfall make

7221-472: The tilt of the earth changes between 22° and 24.5°. At present, it is in a dry period, but it is expected that the Sahara will become green again in 15,000 years. When the North African monsoon is at its strongest, annual precipitation and subsequent vegetation in the Sahara region increase, resulting in conditions commonly referred to as the " green Sahara ". For a relatively weak North African monsoon,

7308-478: The total area) receives an average of 5 millimetres (0.2 in) or less. The annual average rainfall is virtually zero over a wide area of some 1,000,000 square kilometres (390,000 sq mi) in the eastern Sahara comprising deserts of: Libya, Egypt and Sudan ( Tazirbu , Kufra , Dakhla , Kharga , Farafra , Siwa , Asyut , Sohag , Luxor, Aswan, Abu Simbel , Wadi Halfa) where the long-term mean approximates 0.5 millimetres (0.02 in) per year. Rainfall

7395-403: Was initially counteracted by the monsoon , which brought rain further north than it does today. By around 4200 BCE, however, the monsoon retreated south to approximately where it is today, leading to the gradual desertification of the Sahara. The Sahara is now as dry as it was about 13,000 years ago. Lake Chad is the remnant of a former inland sea, paleolake Mega-Chad, which existed during

7482-470: Was just one tenth the rainfall around 125 kya. In the southern Negev Desert speleothems did not grow between 185 and 140 kya ( MIS 6), 110–90 (MIS 5.4–5.2), nor after 85 kya nor during most of the interglacial period (MIS 5.1), the glacial period and Holocene . This suggests that the southern Negev was arid-to-hyper-arid in these periods. During the Last Glacial Maximum (LGM) the Sahara

7569-575: Was more extensive than it is now with the extent of the tropical forests being greatly reduced, and the lower temperatures reduced the strength of the Hadley Cell . This is a climate cell which causes rising tropical air of the Inter-Tropical Convergence Zone (ITCZ) to bring rain to the tropics, while dry descending air, at about 20 degrees north , flows back to the equator and brings desert conditions to this region. It

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