An Arab state occupying a fourth of the Sahara desert. Sahara Desert, Egypt: description, photo, where it is on the map, how to get there. Are there rivers and lakes in the Sahara desert

SAHARA DESERT - INTERESTING FACTS.

The Sahara is the largest desert on Earth, with an area of ​​about 9 million km2, which is slightly smaller than the area of ​​the United States of America. Sahara is located in North Africa, on the territory of more than ten states (Egypt, Libya, Tunisia, Algeria, Morocco, Western Sahara, Mauritania, Mali, Niger, Chad, Sudan). The Sahara does not lend itself to categorization within a single desert type, although the sandy-stony type is predominant. Many regions are distinguished in the desert: Tenere, Great Eastern Erg, Great Western Erg, Tanezruft, Hamada el-Hamra, Erg Igidi, Erg Shesh, Arabian, Libyan, Nubian deserts. The name "Sahara" is an Arabic translation of the Tuareg word "tenere" meaning desert.

In 2008, an international team of scientists from Germany, Canada and the United States, as a result of research, found that the Sahara turned into a desert about 2,700 years ago as a result of a very slow climate evolution. Scientists managed to draw such conclusions based on the study of geological deposits raised from the depths of Lake Yoa, located in northern Chad. According to research results, about 6 thousand years ago, trees grew in the Sahara and there were many lakes. Thus, this work of scientists refutes the existing theory about the transformation of this part of Africa into a desert 5.5 thousand years ago and the fact that the desertification process took only a few centuries. About 160 thousand mirages are observed annually in the Sahara. They are stable and wandering, vertical and horizontal. Even special maps of caravan routes were compiled with an assessment of the places where mirages are usually observed. These maps indicate where wells, oases, palm groves, mountain ranges appear.

Sahara has a combined climate: subtropics and tropics.

The local conditions are practically unsuitable for human habitation, but the nomadic tribes (Tuareg and Teda) probably cannot imagine another life and feel great in the world's largest uninhabited territory.

Geographically, the Sahara is rocky. It includes underground rivers, which sometimes go outside, forming oases.

There are dunes that reach a height of up to 180 meters.

It may sound strange, but the peaks in the desert are covered with snow in winter. The eastern part of the Sahara, the Libyan Desert, is dry and has several oases.

The Sahara receives only 20 cm of rain per year. This is one of the reasons that only 2 million people live here.

During the last Ice Age, the desert was larger than it is now. The Sahara has one of the most brutal climates in the world. A predominantly northeasterly wind often leads to sandstorms.

In the desert there is the City of Tidikelt, which has not received a single drop of rain for ten years.

The average temperature in the Sahara is 30 degrees Celsius, and the maximum is 50 degrees, in winter the temperature often drops below zero;

Only a few animals can survive in the Desert - Camels, sand snakes, scorpions, monitor lizards.

About 500 species of flora survive here;

Amy Coussi is the highest point in the Sahara mountains. Its height is 3415 meters.

Sometime in tropical forests herds of elephants roamed and leopards hunted. A dense network of rivers and lakes covered the steppes, and caravans loaded with gold, slaves and ostrich feathers crossed the sands. And all in the same area! Sahara Desert occupied a third of Africa, almost all of its north. In terms of area, the Sahara is only slightly inferior to the United States, it now freely accommodates a dozen countries. But there are half as many inhabitants here as in St. Petersburg.

On the maps, the Sahara desert is depicted as a huge yellow spot, which is probably why most people imagine it as a boring plain with endless sands. In fact, the Sahara landscapes are surprisingly diverse. Mountains, massifs of bushes, crushed stone and gravel, steppes and scorched clay plains stretch here. There are oases where life is in full swing, and around - dry river valleys, salt marshes and lakes, scattered huge stones and rocky hills. And, of course, the sands, from which the wind forms bizarre reliefs - labyrinths, wavy fields and dunes as high as a 60-story (!) skyscraper. Here you can hear the "singing sands": moving, dry hot grains of sand create sounds resembling squeaking, grinding, rattling, grumbling of a dog, a vibrating rumble that is heard 10 km away.

"Sugar Pump"

The climate of the Sahara is controlled by an invisible conductor - the wind. Above the equator, the air heats up strongly, rises and goes towards the poles. On the way, it cools, sinks in the north of the Sahara and returns to the equator, replacing the heated, rising portions of air. This scheme is called the “Sahara pump”, and the air currents that constantly rush from the tropics to the equator are the trade winds.

Flying over the north of the continent, the dried trade wind carries away the remaining moisture from the surface of water bodies and land. Already at a speed of 10 m / s, it pulls it out even from the soil, and the roots of the plants are deprived of nourishment. And when the wind intensifies, it carries away the very fertile soil. In addition to the trade winds, they walk here local winds- khamsin, ghibli, sirocco. They With hurricane speed(up to 40 m / s) carry sand and heat to the north, to Spain, Italy. In the calm over the Sahara hang "dry fogs" - fine dust.

Climate of the Sahara.

In the Sahara, summer temperatures around +50°C are common. On stones and sand, you can fry fried eggs without making a fire. Daytime heat is replaced by night cold (up to +15°С). Rocks burst from such drops!

In the hot air, mirages are frequent - imaginary reflections of what lies beyond the horizon. Since stable caravan routes have developed in the Sahara, mirages are often seen in the same places. Even maps have been drawn up, where the places of appearance of 1500 mirages are indicated, and conditional icons show what can be seen where: an oasis, the ruins of a fortress, a well, mountains, etc.

Receiving with an excess of solar heat, the Sahara languishes from a lack of moisture. In many regions, rain has been waiting for years. Sometimes its drops do not reach the ground, drying up on the way.

Snow in the Sahara does happen, but it's always a worldwide sensation. This happened in 2016, and before that - in 1979!

Through the sands, rainwater easily seeps into the ground, and over millions of years, real freshwater lakes have formed above the water-resistant layers. In some places, underground water is squeezed closer to the surface. In such places, oases have long been formed - with drinking springs, palm trees, etc.

The Sahara has the driest air in the world. Clouds in the sky here are rare guests. For this reason, the heat is even greater, and the Eastern Sahara is one of the most illuminated places in the world. Here the Sun shines an average of 11 hours a day throughout the year.

How did the Sahara Desert come about?

Millions of years ago, the land from Spain to Mongolia was flooded by the Tethys Ocean. Whales frolicked in it, dinosaurs roamed the shores. Then, when mountain systems began to rise from the depths, the ocean receded. Its remnants formed the Mediterranean, Black, Azov Seas, the Caspian and the Aral. And the current Sahara - former bottom Tethys. It is not surprising that the skeletons of extinct animals have long been found in the desert from Morocco to Egypt. For example, 45-ton paralithans, Egyptosaurs and other monsters.

Approximately 9,000 years ago, the local coastal forests were replaced by African steppes - savannahs: deep rivers and lakes, a carpet of dense grasses, light forests. Herds of giraffes, elephants, antelopes, buffaloes, rhinos, flocks of ostriches and lions roam. People quickly mastered the fertile land - they hunted, fished, kept livestock, settled along the rivers. On the rocks, now lost in the sands, entire galleries of graffiti have been found - images and inscriptions that confirm this. Why isn't it right now? There is no unity among scientists here. Some people explain everything by the arrival of aliens. But there are also more real assumptions.

Hypothesis 1. The climate has become "not the same." It used to be hotter and the sea level higher. The air over the equator was getting hotter, which meant it retained heat longer and cooled further than it does now over the Mediterranean. Having descended, the trade winds were saturated with its moisture, rushed to Africa and brought rains and fogs. They created the prosperity of the Sahara.

Hypothesis 2. The earth swayed in the wrong direction. During the movement of the Earth around the Sun, the tilt of its axis is not constant. As a result, the planet receives a different amount of solar heat and light, and the seasons alternate. Over the millennia, this inclination and the orbit itself change markedly. Therefore, global climate change is coming. It is possible that the great drought in northern Africa is just such a case.

Hypothesis 3."Global flood". Fossilized bones of whales, sharks, rays, turtles, mollusk shells are found in the Sahara shallow. And the ocean had existed for millions of years, kilometer-long layers of marine sediments should have been lying above the bones. Where are they? It is possible that they were carried away by a real flood, the legends of which are kept in the Bible and folklore. streams ocean water washed away the top layer of soil and brought the remains of animals. The root cause of the flood could be the fall of a huge meteorite, which caused a tsunami and turned into dust and sand mountain ranges.

Hypothesis 4. With my own hands. Perhaps the formation of the Sahara is the first ecological catastrophe in the history of mankind. The nomadic way of life does not focus on the concern for the preservation and renewal natural environment. A nomad - he is here today, tomorrow there. Together with their herds that eat and trample the greens. Deprived of a grid of roots, the soil is easily blown out, washed off. The bare soil and the air above it warms up more, a zone of high pressure arises, and the winds blow not here, but from here, keeping the clouds away.

Most likely, the Sahara arose under the influence of several natural factors, which exacerbated the unreasonableness of man. And even now… Laying tracks, exploration and production of oil and gas, car rally – all this destroys the fragile ecosystems of the desert.

Sahara Desert. Plants. Country of dates and feneks.

The word "desert" was invented by our ancestors to designate the property of a vast landscape that struck them - its "emptiness", that is, uninhabited. To live here permanently, indeed, is almost impossible. But there are extreme sports among plants and among animals.

For plants, the Sahara could become a paradise - a lot of light, heat, mineral salts. But without water, you yourself understand ... Nevertheless, about 3,000 plant species have been found in the desert, and one in four cannot be found outside it. Many species live only where there is water, in oases - with date palms, cypresses, vegetables, citrus fruits, pomegranates, cereals. And in those that grow outside the oases, botanists have identified a lot of adaptations that allow you to overcome the lack of moisture:

• dense and extensive network of surface roots - allows you to effectively absorb the moisture of rare rains, morning fogs and dew before everything dries;
• deep (up to 30 m!) roots - get to groundwater, penetrate through cracks into the thickness of the rocks;
• the leaves are narrow, small, covered with hairs (wormwood), wax, turned into spines (cacti) or scales (saxaul) - in order to evaporate less moisture;
• thickening of stems and leaves, which turn into fleshy pantries of water (aloe);
• storage of reserves of moisture and nutrients underground - in rhizomes, bulbs, tubers;
• the roots are covered with thick bark or a case of hardened sap and sand and do not dry out when the soil is blown off them by the wind;
• the stem grows very quickly and / or the roots grow in any of its places - protection from falling asleep with sand;
• a very short period of life - sometimes for several spring days plants have time to bloom, form seeds, and they lie and wait (sometimes for years) until “life gets better”;
• the development of solonchaks - here from the depths along the soil capillaries all the time moisture and salts are pulled up;
• withstand almost complete drying, but recover very quickly after rains.

Sahara desert and wildlife.

Desert animals also have to solve the problem of water shortage. Some hide during the day, and are active during cool hours, from dusk to dawn. Thicker body coverings protect scorpions and beetles from moisture loss. There are many species that can not drink for a long time (or even never) - they lack the meager moisture that is always in food.

Reptiles feel good in the Sahara - cobras, vipers, chameleons and others. Densely covered with scales, they are protected from moisture loss. The skink lizard can literally “swim” in the sand: having instantly dived into it, it rows with its feet and makes its way through the sand at a speed of up to 90 cm per minute.

Many prefer to live not among clay and rubble, but in the sands, where it is easier to burrow, arrange underground holes and wait out the heat there (jerboas and other small rodents). A business card of the Sahara could serve as a funny fennec fox - smaller than our usual cat, but with huge ears. Ears allow you to quickly give off excess heat (protection against overheating). And, of course, together with big eyes, they help to hunt mice and bugs at night. The smallest animal of the cat family lives in the Sahara - the dune cat. There are also antelopes - gazelles, and monitor lizards that look like small crocodiles.

You will not believe it, but ... toads also live here. And not off the banks of the Nile, but in the Central Sahara. They doze, buried deep in the clay soil, eat nothing and barely breathe, But as soon as a good rain passes, every large puddle is teeming with toads. They lay eggs, there is an accelerated development of tadpoles, and when the puddle dries up, a new generation of toads is already settled in the dungeon. Desert snails can remain in underground hibernation for more than one year.

The Sahara is home to some of the most heat-tolerant animals, the satin runner ants. They are active at air temperatures up to +70°C. Their long legs allow them to hold their bodies high above the hot ground. Their upper body is covered with silvery hairs that reflect sunlight. And the hairs on the bottom, like radiator plates, remove excess heat from the body. Runners get out of their holes to the surface when their enemies - lizards hide from the heat. Insects scurry about, collecting food for 10 minutes, and then go underground too - it gets hot for them too.

And for humans, camels have been the most important desert animals for centuries. True, there are no wild ones in the Sahara for a long time, but caravans of domesticated camels slowly cross it all the time.

The Sahara desert is turning... turning...

In the 19th-20th centuries, plans were hatched in Europe to change the Saharan climate, to restore the lost prosperity of these lands. For example, more than once it was proposed to create a “Sahara Sea”: to lay a canal that would connect the Mediterranean Sea with relief depressions in the north of the desert. They say that a man-made reservoir will increase the humidity of the air, and the trade winds will carry this moisture, pouring rain over the desert. The project “failed” - calculations showed that the lowlands are small, most of the desert lies above sea level, so it will not be possible to create a stable reservoir.

In 2008, the Sahara Forest project was born. British engineers proposed not only to plant greenery in the desert, but to install powerful solar power stations and a network of greenhouses between forest plantations on sea ​​water. According to the plan, circular mirrors at the stations will collect sunlight, use it to heat water in a boiler, the steam of which will turn turbines. They will provide energy for distillers, fresh water will go to greenhouses. And the population will receive water for drinking and irrigation, electricity and agricultural products. The project has aroused interest in the Middle East, in the Arabian Emirates, but the political situation in North Africa does not yet give hope for the transformation of the Sahara.

The same can be said about the Great Man-Made River project, which Libya undertook to put into practice: the supply of an underground fresh water through a network of pipes covering almost the entire country. Water came to cities and villages, in the south, in the desert, groves of date palms, gardens and fields turned green, but all work was interrupted Civil War (2011–2014).

Meanwhile, the Sahara continued its offensive, inexorably advancing towards the equator. Back in 1974, the Green Wall program was launched in Algeria. Here they began to plant strips of trees along roads and oases. Eucalyptus and pine trees formed a belt 1500 km long. He kept the soil from weathering, reduced the speed of dry winds. The expansion of the Sahara in this area has slowed down.

Assessing this success, the African Union in 2010 undertook the Great Green Wall project. In fact, it is an extended continuation of the Algerian program. Across the entire continent, from Somalia to Senegal, the planting of a continuous green ribbon 15 km wide and 7775 km long has begun. Of course, huge costs. Of course, there are no guarantees that what has been planted will take root, that local residents will not cut down trees for firewood, and so on. But something needs to be done!

Meanwhile, satellite imagery(2002) showed that in the west, the Sahara desert began to recede. Dense grass is returning to pastures, acacias are growing, ostriches and antelopes have appeared. Ecologists do not exclude that this is the result - oddly enough - of global warming. The warmer the air, the more water vapor it can hold. As a result, winds bring more abundant and frequent rains. Whether the trend will continue is unknown. Sahara Desert after all, she is also famous for the fact that she is able to present surprises.

About ten thousand years ago, the territory where the most big desert our planet, the Sahara, was covered with grass, low shrubs and was densely populated. After the fact that our planet slightly changed the tilt of its axis, the climate began to change gradually, it became hot, the rains stopped - and many representatives of the animal world left the resulting desert.

Sahara (translated from Arabic - "desert") is the most large desert of our planet, which is located in northern Africa and is located on the territory of ten states. On geographical map it can be found at the following coordinates: 23° 4′ 47.03″ s. w., 12° 36′ 44.3″ e. d.

The Sahara occupies about thirty percent of the African continent, and its area is about 9 million km2:

• From east to west, the length of the desert is 4800 km: the Sahara begins off the coast of the Atlantic Ocean and ends off the coast of the Red Sea.
• The length of the Sahara from south to north ranges from 800 to 1200 km. The desert begins in the north of the mainland near the coast of the Mediterranean Sea and the Atlas Mountains, the southern border is limited to 16 ° N. sh., in the region of sedentary ancient dunes, south of which begins the tropical savannah of the Sahel, a transitional area between the desert and the fertile soils of Sudan.

When exactly on the territory of the African continent the Sahara desert was formed, scientists do not have a common opinion: earlier its age was estimated at 5.5 thousand years, then at four, recently they began to lean towards the idea that it is even younger, and its lands became desert only about three thousand years ago.

The desert is located in the northwest of the stable ancient African platform, so ground trembling is now rarely observed. In the center of the platform, from west to east, the relief rises: one of the largest high-mountain regions of the desert are the Ahaggar and Tibesti plateaus, where, unlike the rest of the Sahara, snow falls for a short time almost every year.

From the northern and southern parts of the uplifts there are deflections of the platform, where in former times the sea was located, and therefore the presence of marine sedimentary rocks is characteristic of the soil. In the south of the desert, the deflection of the platform led to the formation large lakes, which are the main suppliers of fresh water in their region. First of all, we are talking about Lake Chad and the Ounianga group of lakes.

Sands occupy only a fourth of the Sahara, while the thickness of the sand layer is about 150 meters. Rocky soil predominates: it occupies about 70% of the desert area, the rest is volcanic mountains, as well as pebble and sand-pebble soil.

There are also many aquifers (sedimentary rocks with varying degrees permeability, the cracks and voids of which are filled with water), which are the main suppliers of water to oases.

Sometimes fertile lands are also found in the desert - mainly near oases that take water from underground rivers and reservoirs, the water of which, due to its own pressure, was able to reach the ground.

On the map of Africa, the Sahara is divided into several regions:

• Western Sahara - located in northwestern Africa, the territory is characterized by coastal lowlands that turn into elevated basement plains and plateaus.
• The central highlands of Ahaggar - on the map is located in the south of Algeria, the highest point is Mount Tahat with a height of 2918 meters, so snow often falls here in winter.
• The Tibesti mountain plateau is located in the center of the desert, in the north of the state of Chad and partly in the south of Libya. highest point The plateau is the Emi-Kushi volcano, almost 3.5 km high, on the top of which snow falls annually.
• The Tenere Desert is located in the south-central Sahara. It is a sandy plain with an area of ​​\u200b\u200babout 400 thousand km2, which is located in the northeastern part of Niger and in western Chad.
• The Libyan Desert - on the map of Africa, it is located in the north and is the driest region of the desert.

Climate

Sahara is the hottest and hottest place on our planet: even the driest desert in the world, Atacama, which is located in South America, cannot be compared with it.

The weather here in summer is extremely hot: the air temperature at this time often exceeds 57°C, and the sands heat up to 80°C. At the same time, the Sahara desert is one of the few places on our planet where evaporation significantly exceeds the amount of precipitation (with the exception of narrow coastal strips). While the average precipitation is only 100 mm (while in the center they may not be for several years in a row), it evaporates - from 2 to 5 thousand mm of moisture.

Conventionally, the Sahara can be divided into two climatic zones, northern (subtropical) and southern (tropical):

The northern part of the desert is characterized by hot summers (up to 58°C) and cold winters (especially cold weather in the mountains, where temperatures can drop to -18°C). The annual rainfall is 80 mm, rainy weather here from December to March and in August, while thunderstorms and even severe short-term floods are not uncommon. In winter, the high plateaus of Ahaggar and Tibesti receive a short snowfall almost every year.

The south is characterized by mild winters, and at the end of a hot and dry period, rains fall. In the mountainous regions, there is little rainfall, and it falls evenly throughout the year. In the lowlands, rains fall in summer, often accompanied by thunderstorms, with about 130 mm of precipitation per year. In the west, near the coast of the Atlantic Ocean, higher humidity than in the rest of the Sahara, there are often fogs.

The difference between daytime and nighttime air temperatures in the Sahara is often about forty degrees: average temperature in the center of the desert in July is 35 °C, while at night the air temperature drops to +10 or +15 °C. The weather here is warm even in winter: the temperature of the coldest month of the year is + 10 ° C (therefore, snow is an extremely rare phenomenon).

The climate of the Sahara is greatly influenced by constantly blowing strong winds, especially in the north of the desert (only 20 days a year are calm). The winds blow mainly from north to east: the movement of humid air masses of the Mediterranean air stops the mountain range of the Atlas Mountains.

As for the air currents that move from the south, when they reach the central part of the desert, they manage to lose moisture. Therefore, the winds in the northern part of the desert have a particularly destructive force. They move at a speed of about 50 m / s and, raising dust, sand, small stones to a height exceeding a thousand meters, cause tornadoes and severe sandstorms, often moving dunes.

Water resources

the only river North Africa, which passes through the eastern part of the Sahara towards mediterranean sea is the Nile, whose length is 6852 km (the river is the second longest after the Amazon, and flows through South America).

Since a large part of the water evaporates as you move through the desert, its two tributaries, the White and Blue Nile, which flow into it in the southeast of the desert (they are very clearly distinguishable on the map), play an important role. In the 60s of the last century, between Egypt and Sudan, the Nasser reservoir was created, the total area of ​​​​which exceeds 5 thousand km2.

In the south of the Sahara, several river flows flow into Lake Chad, the area of ​​\u200b\u200bwhich ranges from 27 to 50 thousand km2 (depending on precipitation in the region), after which part of the water leaves the lake - and the water continues to flow into northeast direction while replenishing watersheds.

In the southwest flows the Niger River, which flows into the Gulf of Guinea of ​​the Atlantic Ocean. This river is interesting in that starting almost near the ocean, 240 km from the coast, it flows in the opposite direction, into the Sahara, after which it turns sharply to the right and continues on its way in a southeast direction (the shape of the river, if you look at the map of Africa, looks like a boomerang).

IN northern part desert water comes from wadi streams, temporary streams of water that appear after heavy rains and flow down the mountains. Wadis also feed the desert soil in its central part. A lot of rainwater is in the dunes: once in the sand, the water seeps through the slopes and flows down.

Under the sands of the desert there are huge pools of groundwater, thanks to which oases are formed (there are especially many of them in the north of the Sahara, while in the south the aquifers are located deeper).

Another source of water in the largest desert on the planet is located on the outskirts and in mountain ranges of relict lakes (the remains of former seas), often swampy and salty, although fresh water is often found among them (for example, the water of most lakes of the Unianga group).

Flora

There is little vegetation in the Sahara - mostly shrubs, herbs and trees that grow near a natural reservoir, along a wadi or in high-altitude regions, among them olives, cypress, dates, thyme, citrus fruits.

In areas where there is little water supply, only those types of vegetation are found that tolerate drought well. There are no plants at all in rocky massifs, in places where sands accumulate.

Fauna

Almost 4 thousand representatives of the animal world live in the desert, most of which are invertebrates. Animals of the Sahara desert live mainly near the water (they are practically not found in arid regions) and are nocturnal.

Most of the animals are monitor lizards, cobras, lizards, chameleons, snails. Crocodiles, frogs, crustaceans are found in reservoirs. There are about sixty species of mammals, among them - cheetah, spotted hyena, sand fox, mongoose.

About 300 species of birds live in the Sahara, 50% of them are migratory. These are, first of all, ostriches, African owl, trumpet and desert crows and others.

Desert and people

Despite huge area, the desert is sparsely inhabited: only 2.5 million people live here. Some peoples lead a nomadic lifestyle, but most prefer to settle down. People settle only near oases, as well as in the valleys of the Nile and Niger rivers, where in order to survive on their own and feed livestock, there is enough water and vegetation. At the same time, cattle breeding: goats and sheep prevails over fishing and hunting.

10 states: Algeria, Egypt, Western Sahara, Libya, Mauritania, Morocco, Niger, Sudan, Tunisia, Chad

The Sahara is the most famous desert. No wonder, because it is the largest desert in the world. It is located on the territory of 10 African states.

The oldest text in which the Sahara appears as the "great" North African desert dates back to the 1st century AD.

A truly endless sea of ​​sand, stone and clay scorched by the sun, enlivened only by rare green spots of oases and a single river - this is what the Sahara is.

"Sahara" or "Sahra" is an Arabic word, it means a monotonous brown desert plain. Say this word aloud: do not you hear in it the wheezing of a man choking with thirst and sizzling heat? We Europeans pronounce the word "Sahara" softer than Africans, but it also conveys to us the formidable charm of the desert. This is the hottest area on Earth (the city of Tripoli recorded an air temperature of +58°C). There is no rain in the Sahara for years, and if it does, the drops often do not reach the ground - they dry up in the air.

But what are the feelings of a person who first found himself in the Sahara. In the morning, a huge fireball of the sun rises and everything around is heated: the air is hot and dry, which burns the lips, and it is impossible to stand on the ground. An Arabic proverb says: "In the Sahara, the wind rises and falls with the sun." The wind can bring dust storms, or it can pick up a terrible "song of the sands", and then a terrible whirlwind - simum - will sweep over the desert. At night, the unbearable heat is replaced by piercing coolness. Even stones cannot withstand such sharp drops - they burst with a loud crack. Such stones were called "shooting" stones in the Sahara, and the inhabitants of the desert say: "the sun in our country makes even stones scream",

The Tuareg, forever roaming the most remote and uninhabited regions of the Sahara, are called "blue ghosts". A blue veil that covers the face so that only a strip for the eyes remains, the young man receives at a family holiday when he turns eighteen years old. From that moment on, he becomes a man, and never again in his life, day or night, does he remove the veil from his face and will only move it a little away from his mouth while eating.

location

The Sahara extends from the Atlantic Ocean in the west to the Red Sea in the east, and from the foothills of the Atlas and the Mediterranean coast in the north to about 15°N. (Lake Chad) in the south, where it borders the savannah zone. Its area is approx. 7700 thousand km2. It is larger than Australia and only slightly smaller than Brazil. In terms of its size, the Sahara is not inferior to Europe with all its islands.

Climate of the Sahara

The climate of the Sahara is extra-arid (tropical, dry and hot, in the north - subtropical). The wet factor is the broad position of the Sahara north and south of the Tropic of the North. This explains the fact that most of the desert is under the influence of the northeast trade wind, which dominates for the most part Sahara throughout the year.

An additional influence on the climate is exerted by the Atlas mountain barrier located in the north, elongated from west to east and preventing the main mass of humid Mediterranean air from penetrating into the desert. In the south, from the side of the Gulf of Guinea, wet masses freely enter the Sahara in summer, which, gradually drying up, reach its central parts.

The extreme dryness of the air, the enormous deficit of humidity, and, accordingly, the exceptionally high evapotranspiration are characteristic of the entire Sahara. According to the precipitation regime in the Sahara, three zones can be distinguished: northern, central and southern.

The aridity of the Sahara also varies in the latitudinal direction, from west to east. On the Atlantic coast, heavy precipitation does not fall, since rare westerly winds are cooled by the Canary Current passing along the coast. Fogs are frequent here.

Air dryness (relative humidity 30-50%), a huge lack of humidity and high evaporation (potential evaporation 2500-6000 mm, which is more than 70 times the amount of precipitation) are typical for the entire Sahara, except for narrow coastal strips. Precipitation in Northern Sahara is predominantly winter, in Southern Sahara - summer; the average annual precipitation in the marginal regions is 100-200 mm, in most of the Sahara plains it is less than 50 mm (usually less than 100 mm in mountain ranges), and in the interior it may not rain for several years in a row. There are several places where rains have never been recorded at all. During rains, usually torrential, dry channels (wadis) quickly turn into turbulent streams and cause floods in the bridles and mudflows in the mountains. During this period, the desert seems to come to life. Numerous streams, rivers, lakes appear in it.

The Sahara as a whole is poorly supplied with water, but compared to other deserts of the world, it is rich in groundwater.

Most of the Sahara is characterized by abundant morning dews (condensation due to low night temperatures), which contribute to the formation of superficial silty crusts. On the peaks of Ahaggar and Tibesti, snow falls for a short time almost every year. Temperatures can reach 56-58°C, approaching the maximum on Earth, but the land surface can warm up to 70-80°C. The average monthly air temperature in July reaches 37.2 ° C (Adrar), the average January temperatures range from 16 to 27 ° C. In winter, frosts on the soil are widespread in the Sahara at night, and night temperatures down to -18 ° C are recorded in the central mountain ranges .

Long winds and multi-day dust (sand) storms are frequent. Storms in the Sahara have extraordinary strength. The wind speed sometimes reaches fifty meters per second (sometimes more; winds of sirocco, shergi, khamsin, harmattan and samum), (thirty meters per second is already a hurricane!). Caravaneers say that sometimes heavy camel saddles are carried away by the wind for two hundred meters, and stones, the size of a chicken egg, roll along the ground like peas. The "Desert Genie" is the name given to the tornado by the Bedouins.

And when there is calm in the Sahara and the air is filled with dust, a “dry fog” known to all travelers arises. At the same time, visibility completely disappears, and the sun seems to be a dull spot and does not give a shadow. Even wild animals lose their bearings at such moments. They say that there was a case when, during the “dry fog”, usually very shy gazelles calmly walked in a caravan, walking between people and camels.

The Sahara influences the climate of many adjacent territories. Winds can carry dust and sand far beyond Africa, Atlantic Ocean or to Europe.

Story

The Sahara has not always been a lifeless land.

As further studies confirmed, even in the Paleolithic period, that is, 10-12 thousand years ago (in glacial period) the climate here was much more humid. The Sahara was not a desert, but an African steppe-savannah. The population of the Sahara was engaged not only in cattle breeding and agriculture, but also in hunting and even fishing, as evidenced by rock paintings in different areas desert.

In many parts of the Sahara, ancient cities were buried under a layer of sand; this may be indicative of a comparatively recent desiccation of the climate.

Scientists at Boston University seem to have found another piece of evidence that the Sahara was not always a desert. According to the Boston University Remote Sensing Center, northwestern region Sudan used to be a huge lake, the area is almost equal to Baikal. Now a huge body of water, which because of its size was called Megalake, is hidden under the sands.

Boston University scientists in the northwestern region of Sudan, in the middle of the Sahara, Dr. Eman Ghoneim and Dr. Farouk El-Baz studied photographic and radar images of the Darfur region in order to accurately determine the location of the lake. According to their scientific data, coastline The lake was once located about 573 meters (plus or minus 3 meters) above sea level.

Researchers suggest that several rivers flowed into the lake at once. The maximum area that Megalake once occupied was 30,750 sq. km. In addition, the authors of the study calculated that at the best of times, the volume of water in the lake could reach 2,530 cubic meters. km.

At present, scientists cannot accurately determine the age of the lake, but state another fact that the size of the Megalake indicates constant rains, due to which the volume of the reservoir was regularly replenished. The find once again confirms that before the territory of the Sahara was not always a desert. She lay within the zone of moderate climate zone and it was covered with plants.

Scientists led by El-Baz also suggest that most of the Megalake has seeped into the soil and now exists in the form of groundwater. This information is extremely important for local residents, as it can be used for purely practical purposes. The fact is that this particular region of Sudan is experiencing a severe shortage of fresh water, and the discovery of groundwater would be a gift for them.

Then, about 5-7 thousand years ago, a drought began, the heat increased, the surface of the Sahara lost moisture more and more, the grass dried up. Gradually, herbivores began to leave the Sahara, predators followed them. The animals had to retreat to the distant forests and savannahs of Central Africa, where all these representatives of the so-called Ethiopian fauna still live. Almost all people left the Sahara for animals, and only a few were able to survive where there was still some water left. They became nomads wandering in the desert. They are called Berbers or Tuareg, and the "father of history" Herodotus called this tribe the Garamantes - after the main city of Garama (modern Germa).

By this time, scientists also attribute the appearance of most of the famous frescoes of Tas-sili-Adzher, a plateau located in the center great desert. The name itself means "plateau of many rivers" and reminds of that distant time when life flourished here. Fat herds and caravans carrying ivory are the central theme of the painting. There are also dancing people in masks and mysterious giant images of the so-called "Martian gods". Much has been written about the latter. The mystery of their origin still excites the minds: either they represent a scene of shamans' rituals, or aliens abducting people.

Relief

Sahara is, in fact, not the name of one particular desert, but the collective name of a number of deserts connected by a single space and climatic features. Her East End occupied by the Libyan desert. On the right bank of the Nile, up to the Red Sea, the Arabian Desert extends, to the south of which, entering the territory of Sudan, the Nubian Desert is located. There are other, smaller deserts. Often they are separated by mountain ranges with fairly high peaks.

There are powerful mountains with peaks up to 2500 thousand meters in the Sahara, and the extinct crater of the Emi-Kusi volcano, whose diameter is 12 km, and plains covered with sand dunes, basins with clay soil, salt lakes and salt marshes, blooming oases. All of them replace and complement each other. There are also giant cavities. One of them is located in Egypt in the northeastern part of the Libyan Desert. This is Qatar, the driest depression on our planet, its bottom is 150 m below sea level.

In general, the Sahara is a vast plateau, a table, the flat character of which is broken only by the depressions of the Nile and Niger valleys and Lake Chad. On this plain, only in three places do truly high, albeit small in area, mountain ranges rise. These are the highlands of Ahaggar (Algeria) and Tibesti (Chad) and the Darfur plateau, rising more than three kilometers above sea level.

The mountainous, gorge-cut, absolutely dry landscapes of Ahaggar are often compared to lunar landscapes.

To the north of them are closed saline depressions, the largest of which turn into shallow salt lakes during the winter rains (for example, Melgir in Algeria and Dzherid in Tunisia).

The surface of the Sahara is quite varied; vast spaces are covered with loose sand dunes, stony surfaces are widespread, worked out in bedrock and covered with crushed stone (hamada) and gravel or pebbles (regi).

In the northern part of the desert, deep wells or springs provide water to oases, thanks to which date palms, olive trees, grapes, wheat and barley are grown.

All the oases of the Sahara are surrounded by palm groves. Date palms are the basis of life for the locals. Dates and camel milk are the main food of fellah farmers.

It is assumed that the groundwater that feeds these oases comes from the slopes of the Atlas, located 300–500 km to the north. All life is concentrated mainly in the marginal parts of the Sahara. The largest human settlements are concentrated in northern regions. Naturally, there are no roads connecting the oases. Only after the discovery and development of oil, several highways were built, but along with them, camel caravans continue to run.

In the east the desert is cut by the Nile valley; since ancient times, this river has provided residents with water for irrigation and created fertile soil, depositing silt during annual floods; the regime of the river changed after the construction of the Aswan Dam.

Oil production

In the 1960s, oil and natural gas production began in the Algerian and Tunisian sectors of the Sahara. The main deposits are concentrated in the Hassi-Messaoud region (in Algeria). In the late 1960s, even richer oil fields were discovered in the Libyan sector of the Sahara. The transport system in the desert has undergone significant improvements. Several highways crossed the Sahara from north to south, but did not displace the time-honored camel caravans.

Mirages

Few people dare to travel in the Sahara. During a difficult journey, mirages may occur. Moreover, they always come across in approximately the same place. Therefore, it was even possible to draw up maps of mirages, on which 160 thousand marks were made on the location of mirages. These maps even mark what exactly is seen in one place or another: wells, oases, palm groves, mountain ranges, and so on.

It is difficult to find a more beautiful sight than the sunset in the desert. Perhaps only the aurora borealis makes a greater impression on the traveler. The sky in the rays of the setting sun each time strikes with a new combination of shades - it is both blood-red and pink-pearl, imperceptibly merging with pale blue. All this is piled up on the horizon in several floors, it burns and sparkles, growing into some kind of bizarre, fabulous forms, and then gradually fades away. Then, almost instantly, an absolutely black night sets in, the darkness of which even the bright southern stars cannot dispel.

These days, the Sahara is not so difficult to access. From the city of Algiers on a good highway to the desert can be reached in one day. Through the picturesque gorge El Kantara - "Gateway to the Sahara" - the traveler finds himself in amazing places. To the left and right of the road, which runs through a rocky and clay plain, small rocks rise, which the wind and sand have given intricate outlines. fairytale castles and towers.

Flora

In the Northern Sahara, the influence of the Mediterranean flora is significant, and in the south, species of the Paleotropical Sudanese flora widely penetrate into the desert. About 30 endemic genera of plants are known in the flora of the Sahara, belonging mainly to the families of cruciferous, haze and Compositae. In the most arid, extra-arid regions of the Central Sahara, the flora is especially poor.

So, in the south-west of Libya, only about nine species of native plants grow. And in the south of the Libyan desert, you can travel hundreds of kilometers without finding a single plant. However, there are regions in the Central Sahara that are distinguished by comparative floristic richness. These are the desert highlands of Tibesti and Ahaggar. In the Tibesti highlands, near water sources, willow-leaved ficus and even venus hair fern grow. On the Tassini-Adgenre plateau, northeast of Ahanar, there are relic plants: individual specimens of the Mediterranean cypress.

The Sahara is dominated by ephemera, appearing for a short time after rare rains. Perennial xerophytes are common. The most extensive in terms of area are grass-shrub desert plant formations ( different kinds cereal of Aristides). The tree-shrub layer is represented by free-standing acacias, low-growing xerophytic shrubs - cornulaca, randonia, etc.). In the northern belt of grass and shrub communities, jujube is often found.

In the extreme west of the desert, in the Atlantic Sahara, special plant groups are formed with the dominance of large succulents. Cactus euphorbia, acacia, dereza, sumac grow here. An Afghan tree grows near the ocean coast. At altitudes of more than 1700 m, here (highlands and plateaus of the Central Sahara) begin to dominate: cereals, feather grass, bonfire, ragwort, mallow, etc. The most characteristic plant of the Saharan oases is the date palm.

Fauna

In the Sahara, there are about 70 species of mammals, about 80 species of nesting birds, about 80 species of ants, more than 300 species of black beetles, and about 120 species of orthopterans. Species endemism in some groups of insects reaches 70%, in mammals it is about 40%, and in birds there are no endemics at all.

Of the mammals, rodents are the most numerous. Representatives of the family of hamsters, mice, jerboas, squirrels live here. Gerbils are diverse in the Sahara (red-tailed gerbil is common). Large ungulates in the Sahara are not numerous, and the reason for this is not only the harsh conditions of the desert, but also the long-term persecution of them by man. The largest antelope in the Sahara, the aryx, is slightly smaller than the addax antelope. Small antelopes, similar to our gazelles, are found in all regions of the Sahara. On the coasts and plateaus of Tibesti, Ahaggar, as well as in the mountains on the right bank of the Nile, a maned ram lives.

Among predators there are: a miniature fox, a striped jackal, an Egyptian mongoose, a dune cat. Birds in the Sahara are not numerous. Larks, hazel grouse, desert sparrow are common. In addition, there are: oystercatcher, desert raven, eagle owl. Lizards are numerous (crest-toed lizards, gray monitor lizard, agamas). Some snakes are excellently adapted to life in the sands - sand efa, horned viper

The one-humped camel, whose appearance symbolizes the Sahara desert, deserves special attention.

Museum of Man

The Great Desert is full of human footprints left on purpose. Some drawings and engravings of the Sahara are more than 10 thousand years old. On the most ancient - wild animals: elephants, giraffes, rhinos, hippos, ostriches, antelopes, often gigantic. Sometimes the opposite is true: following the guide, you crouch down under a rock ledge - and find yourself among a herd of palm-sized red cows.

The yellowish-brown and yellow-red background of the rocks and sandstones of Tassili turned out to be an ideal material that preserved the archive of several eras. Hundreds of images of Tassili N "Ajer, discovered, described and copied by the French explorer Henri Lot in the 50s of the XX century, show the life of various peoples who inhabited the massif at different times.

“We were struck,” A. Lot wrote, “with the variety of styles and subjects that we discovered in the study of numerous layers of paintings ... Some drawings were located in isolation, others were complex compositions. We found ourselves, as it were, in the greatest museum of prehistoric art. Two main styles characterize these murals: one is symbolic, more ancient, in all likelihood, of Negroid origin; the other is more recent, clearly naturalistic, in which the influence of the culture of the Nile Valley is felt. ... And if sometimes you can find Egyptian or possibly Mycenaean influence in them, the most ancient of them certainly belong to an unknown original art school.

But the Sahara still holds many mysteries. One of them is in the desert part of Niger, on the Adrar Ma-det plateau. Here are laid out from rubble stone circles perfect concentric shape. They are located at a distance of almost a mile from each other, as if on arrows directed exactly to the four cardinal points. Who created them, when and for what, while there is no clear answer to these questions!

Structure Guell Er Richat, Mauritania

This structure is located on the territory of the Sahara desert, and is clearly visible from space, since its diameter is almost 50 km. It is believed that its oldest ring was formed more than half a billion years ago. But the reasons for its occurrence are not clear. Previously, it was believed that it arose after a huge meteorite hit the Earth, but the bottom of the structure is not flat, and no traces of the impact were found along the edges of the structure itself. Therefore, today most researchers believe that the structure is the result of erosion, but they don’t even try to explain its almost perfectly round shape - this is a mystery.

Tourism

Excursions are offered in the Sahara. This small trips for 2-3 days in the deadly desert. You can ride a camel, but only under the supervision of an overseer. Otherwise, you may find yourself on a beast among the boundless sands. The bravest ones can cross the desert themselves (it is possible, although it seems unrealistic!). But before the trip, you need to consult with a specialist.

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