Winter in the desert. Deserts: characteristics and types The lowest temperature in the desert at night
Where is the Sahara Desert located?
The Sahara Desert is the largest SANDY desert on our planet and it is located in the northern part of the African continent. It also ranks second as the largest desert in the world in terms of area, giving way to the Antarctic Desert. The area of the Sahara occupies about 8.6 million km2 and partially occupies the territory of 10 states. From west to east its length is 4800 m, and from south to north its length ranges from 800 to 1200 meters. At the same time, the size of the desert is not constant; it grows annually by 6-10 km from south to north.
Sahara desert landscape
The landscape of the Sahara consists of 70% of the plains and 30% of the Tibesti and Ahaggar highlands, the stepped plateaus of Adrar-Iforas, Air, Ennedi, Tademait, etc., as well as cuesta ridges.
Climate of the Sahara Desert
The climate of the desert is divided into subtropical in the north and tropical in the south of the desert. In the northern part of the desert, there are large fluctuations in temperature, both annual and average daily. In winter, the temperature can drop to -18 degrees in the mountains. Summer, on the other hand, is very hot. The soil can warm up to 70-80 degrees Celsius.
In the southern part of the desert, temperature fluctuations are slightly less, but also in winter the temperature in the mountains can drop below zero degrees Celsius. Winters are milder and dryer.
The desert is characterized by a large fluctuation in temperatures at night and during the day. This figure is voiced up to 30-40 degrees difference between night and day temperatures! Therefore, it is sometimes impossible to do without warm clothes there at night, as the temperature can drop below zero. Also in the desert there are often sandstorms, in which the wind can reach up to 50 meters per second. The central parts of the desert may not see rain for years, and other parts may even experience heavy downpours. In other words, the Sahara desert is full of surprises in terms of weather.
The Sahara Desert is an amazing place. It is incredible how animals, plants, and people have been able to adapt to life in this part of the earth, given the constant drought and heat.
1) In terms of size, the desert is like half of Russia, or the whole of Brazil!
The Sahara Desert is the largest desert in the world, covering 30% of Africa. But this is half of the Russian Federation, or the entire area of Brazil, which is in fifth place in terms of the area of countries on Earth.
2) "Sea without water." In Arabic, the Sahara is a desert, and some people called it the “Sea without Water”, because once upon a time there were many rivers and lakes in its place.
3) Mars on Earth. The desert dunes move from a couple of centimeters to hundreds of meters per year, and the dunes themselves resemble the landscapes of Mars! Sometimes they reach a height of 300 meters!
4) There are fewer and fewer oases. Near the oases, villages and cities usually appear, but every year there are fewer and fewer oases.
5) The average temperature in the desert is about 40 degrees Celsius! The sand itself is heated up to 80 degrees Celsius! But at night the temperature can drop to -15 degrees Celsius.
6) Over the past fifty years, storms have begun to appear more and more often, in some places their occurrence has increased forty times!
7) There are 3 million people living in the Sahara. However, earlier there were more people, once upon a time, caravans of merchants passed through the desert, carrying various riches. But the passage through the entire desert took 1.5 years!
8) The roots of some plants are at a depth of 20 meters! In this way, plants try to get water for themselves in order to retain it for a long time and use it carefully.
9) There are about 4 thousand different species of animals and plants in the Sahara.
10) Camels live without water for 14 days, and without food as much as 30! They can smell moisture for 50 kilometers, and drink a hundred liters of water at a time! And they don't sweat at all! Their humps are fat, thanks to which they can exist for a long time without food.
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The highest (up to 100 meters) dunes. Takyrs. The Gobi Desert in Mongolia. Karakum. Dunes. Deserts. Sandstorms. Desert Victoria. Sandy deserts. Deserts of the world. Kalahari. Dune. Great deserts of the world. Deserts of the Arabian Peninsula. Pictures of animals. Sahara. The largest oasis in the Okavango Delta. Peruvian Nazca Desert. main population. Salt marshes. Salt deposits. About 160 thousand mirages.
"Desertification of the Lands" - Lonely ship. The fight against desertification. Degraded areas. Reduction of agricultural areas. Desertification. Map of the desertification of the Earth. Desertification and land degradation. Sand barriers. Desertification types. Causes of desertification. Karakum Canal. Land degradation. Environmental consequences. Distribution in the Russian Federation. Dry lands. Human activity.
"Deserts of the Gobi" - Communities of steppe deserts. Linear dependency. Desert steppes are common in the piedmont plain. Biological potential of dominants and co-dominants in communities. Cold wormwood-serpentine-feather grass community. Mass renewal of Elijah. The annual dynamics of the one-year mass. Significant fluctuations of the above-ground mass. E.I. Rachkovskaya (1977) singled out extremely arid deserts. Distribution of plant communities and dominant species.
"Humidification of deserts" - Deserts in winter and summer. Nuclear COOLERs for the rehabilitation of coastal arid areas. Essence of the project. Decrease in average annual temperatures. Plant. Construction of "Land-cooler". Sands of the Sahara. Upper clouds. Nuclear power complex. Abstracts. Deserts and global warming. arid territories. Spindrift clouds. Farmers throughout Africa. Complex structures. Water vapor in the atmosphere of the seas.
"Deserts of the world on the map" - Collared peccaries. Sahara. An unusual type of jumper. Species composition of desert vegetation. Desert vegetation. Mountain ranges. Deserts of the world. The sun. Green rattlesnake. One-humped camel. Desert types. Deserts of the United States of America. Pronghorn. Oryx. Rocky desert. Inhabitants. Jerboa. Owl elf. American desert. Desert characteristics. Animals of the rocky desert. Deserts of Russia.
"Description of the desert" - The desert fauna has a protective "desert" color. Similarities and differences. Moisture deficiency, especially drinking water. Desert climate. Desert and arctic desert. Soil structure. Deserts. Human activities in the deserts. Xerophilous shrubs and perennial herbs. Animals of the desert and the Arctic desert differ significantly. Low air temperatures in winter. The Arctic desert is devoid of vegetation.
Despite the fact that its very name "desert" comes from such words as "empty", "emptiness", this amazing natural object is filled with diverse life. The desert is very diverse: in addition to the sand dunes that our eyes habitually draw, there are saline, stony, clay, and also snowy deserts of Antarctica and the Arctic. Taking into account the snowy deserts, this natural zone belongs to one fifth of the entire surface of the Earth!
Geographic feature. The meaning of deserts
The main distinguishing feature of the desert is drought. The reliefs of the deserts are very diverse: insular mountains and complex uplands, small hills and layered plains, lake depressions and dried up centuries-old river valleys. The formation of the relief of deserts is greatly influenced by the wind.
Man uses deserts as pastures for livestock and areas for growing some cultivated plants. Plants for feeding livestock develop in the desert thanks to the horizon of condensed moisture in the soil, and desert oases, flooded with sun and water, are exceptionally good places for growing cotton, melons, grapes, peach and apricot trees. Of course, only small areas of deserts are suitable for human activity.
Characteristics of deserts
Deserts are located either next to the mountains, or almost on the border with them. High mountains prevent the movement of cyclones, and most of the precipitation they bring falls in the mountains or foothill valleys on the one hand, and on the other side - where the deserts lie - only a small remnant of rain reaches. That water, which manages to reach the soil of the desert, flows down the surface and underground watercourses, gathering in springs and forming oases.
Deserts are characterized by various amazing phenomena that are not found in any other natural area. For example, when there is no wind in the desert, the smallest grains of dust rise into the air, forming the so-called "dry fog". Sandy deserts can "sing": the movement of large layers of sand generates a high and loud slightly metallic sound ("singing sands"). Deserts are also known for their mirages and terrible sandstorms.
Natural areas and types of deserts
Depending on the natural zones and the type of surface, there are such types of deserts:
- Sandy and sandy-gravel. They are distinguished by great diversity: from chains of dunes devoid of any vegetation, to territories covered with shrubs and grass. Moving through the sandy desert is extremely difficult. Sands do not occupy the largest part of the deserts. For example: the sands of the Sahara make up 10% of its territory.
- Stony (hamadas), gypsum, gravel and gravel-pebble. They are combined into one group according to a characteristic feature - a rough, hard surface. This type of desert is most common on the globe (hamads of the Sahara occupy 70% of its territory). Succulents and lichens grow in tropical rocky deserts.
- saline. In them, the concentration of salts prevails over other elements. Salt deserts can be covered with a hard cracked salt crust or salt bog that can "suck in" a completely large animal and even a person.
- clayey. They are covered with a clayey smooth layer stretching for many kilometers. They are characterized by low mobility and low water properties (the surface layers absorb moisture, preventing it from going deep, and dry quickly during the heat).
Desert climate
Deserts occupy the following climatic zones:
- temperate (Northern Hemisphere)
- subtropical (both hemispheres of the Earth);
- tropical (both hemispheres);
- polar (ice deserts).
The deserts are dominated by a continental climate (very hot summers and cold winters). Precipitation is extremely rare: from once a month to once every few years and only in the form of showers, because. small precipitation does not reach the ground, evaporating in the air.
The daily temperature in this climatic zone varies greatly: from +50 ° C during the day to 0 ° C at night (tropics and subtropics) and up to -40 ° C (northern deserts). Desert air is especially dry: from 5 to 20% during the day and from 20 to 60% at night.
The largest deserts in the world
Sahara or Queen of the Desert- the largest desert in the world (among hot deserts), the territory of which occupies over 9,000,000 km 2. Located in North Africa, it is famous for its mirages, which happen here on average 150,000 a year.
Arabian desert(2,330,000 km 2). It is located on the territory of the Arabian Peninsula, also capturing part of the land of Egypt, Iraq, Syria, Jordan. One of the most capricious deserts in the world, known for especially sharp fluctuations in daily temperature, strong winds and dust storms. From Botswana and Namibia to South Africa extends over 600,000 km2 Kalahari, constantly increasing its territory due to alluvium.
Gobi(more than 1,200,000 km2). It is located in the territories of Mongolia and China and is the largest desert in Asia. Almost the entire territory of the desert is occupied by clay and stony soils. In the south of Central Asia lie Karakum("Black Sands"), occupying an area of 350,000 km 2.
Desert Victoria- occupies almost half of the territory of the Australian continent (over 640,000 km 2). It is famous for its red sand dunes, as well as a combination of sandy and rocky areas. Also located in Australia Great Sandy Desert(400,000 km 2).
Two South American deserts are very notable: Atacama(140,000 km 2), which is considered the driest place on the planet, and Salar de Uyuni(more than 10,000 km 2) - the largest salt desert in the world, the salt reserves of which are more than 10 billion tons.
Finally, the absolute champion in terms of occupied territory among all world deserts is ice desert Antarctica(about 14,000,000 km 2).
Winter in deserts, although warmer than in the semi-desert zone, it is still unusually cold for these low latitudes. The average January temperature in the north of the zone is about -12°, in the south it is close to 0°, the average absolute minimum air temperature is -35-20°. Lake Balkhash and the Aral Sea are ice-bound in winter; Freezing lasts 2.5-3.0 months at the mouths of the Amudarya and Syrdarya rivers. Snow cover about 10 cm high lies for 100 days in the north of the zone and 20-30 days in the southwest. The lack of snow and the short duration of the snow cover make it possible to graze cattle in the deserts in winter. The non-pasture period for sheep in the deserts of Kazakhstan lasts only 30-60 days, and in the Central Asian deserts it is practically absent, except for the relatively rare days with ice and snowstorms.
Spring- the season of the year, refuting the usual ideas about the desert. At this time, there is a rapid increase in air temperature, unusual for other zones. In the area of Kyzyl-Orda, the average daily air temperature passes through 10°C on April 11, and after a decade or a little later, the average daily air temperature passes through 15°C. May in the zone in terms of its temperature conditions (16-20 °) resembles the height of summer in central Russia - July. Moderate positive air temperature in spring is combined with the annual maximum of precipitation, which in the north of the zone falls in May, in the south - in April.
Atmospheric precipitation, together with winter reserves of soil moisture, is sufficient for a short-term but lush development of vegetation. It was at this time that an outbreak of vegetation of ephemers and ephemeroids occurs, especially characteristic of sandy and foothill loess deserts. The animal world is becoming very active. For some desert dwellers, spring is the only period of active life in the year. So, for example, the steppe tortoise is active only from March to May, after the ephemera burns out, it burrows into the ground and lies there until the next spring. A similar way of life leads a sandy gopher.
It is indicative that the lambing of goitered gazelle and domestic karakul sheep is timed to the moment of development of ephemeral-ephemeroid vegetation. At the same time, the growth of the Karakul lamb is characterized by a very high intensity in the first month. “The meaning of this phenomenon is that the lamb in the desert must be ready for the early dry summer, for eating dry hard grasses in summer, it is necessary to have time to work up a sufficient supply of fat.”
Summer in the deserts of the temperate zone, it is even hotter, sunny and dry than in the semi-desert zone. The average temperature in July is about 25-29°, on some days the air temperature in the shade rises above 40°, and the surface of bare soil heats up to 70°. The hot period in the zone is stable and long: the number of days with an average daily air temperature above 20° in the north is 90, in the south - 140. low humidity and high dust content.
Exhausting heat is exacerbated by a negligible amount of precipitation, the amount of which quickly decreases in a southerly direction. For all three summer months, 30 mm of precipitation falls in Irgiz, 19 mm in Kazalinsk, and 11 mm in Turkestan. For comparison, we point out that Moscow, with its moderately warm summers, receives 192 mm of precipitation over the same period. Due to the acute lack of moisture, ephemera and ephemeroids disappear from the grass cover even before the beginning of summer, the most undemanding shrub wormwood and saltwort, which are in a state of semi-rest, stop growing. At the beginning of summer, the budding of cotton occurs, in July - its flowering, in late August - early September, ripening occurs.
Autumn in the first half it is very reminiscent of summer: in September, as in previous months, hot and dry cloudless weather prevails, favorable for the ripening and harvesting of cotton and fruit crops. In the southern half of the zone, the transition of the average daily temperature through 15° occurs around October 1. In the second half of autumn, cloudiness increases, the amount of precipitation increases, which, at low air temperatures, creates conditions for the re-vegetation (greening) of many plants. The first frosts in most of the zone appear in October.
Literature.
1. Milkov F.N. Natural zones of the USSR / F.N. Milkov. - M. : Thought, 1977. - 296 p.