These climatic phenomena make a significant contribution to the pollution of the earth's atmosphere. It is one of the many incredible natural phenomena for which scientists quickly found a simple explanation.

These adverse climatic events are dust storms. They will be discussed in more detail in the following article.

Definition

A dust, or sand, storm is a phenomenon of the transfer of a huge amount of sand and dust by strong winds, which is accompanied by a sharp deterioration in visibility. As a rule, such phenomena originate on land.

These are arid regions of the planet, from where air currents carry powerful clouds of dust into the ocean. Moreover, while representing a considerable danger to humans, mainly on land, they still greatly worsen the transparency of atmospheric air, making it difficult to observe the surface of the ocean from space.

It's all about the terrible heat, due to which the soil dries out a lot and then breaks up into microparticles in the surface layer, picked up by a strong wind.

But dust storms begin at certain critical values ​​\u200b\u200bdepending on the terrain and soil structure. For the most part, they begin at wind speeds in the range of 10-12 m/s. And weak dust storms occur in summer even at speeds of 8 m/s, less often at 5 m/s.

Behavior

The duration of storms varies from minutes to several days. Most often, time is calculated in hours. For example, an 80-hour storm was recorded in the Aral Sea region.

After the disappearance of the causes of the described phenomenon, the dust raised from the surface of the earth remains in the air in a suspended state for several hours, possibly even days. In these cases, its huge masses are carried by air currents for hundreds and even thousands of kilometers. Dust carried by the wind over long distances from the source is called advective haze.

Tropical air masses carry this haze into southern part Russia and all of Europe from Africa (its northern regions) and the Middle East. And western streams often carry such dust from China (center and north) to the coast Pacific Ocean etc.

Color

Dust storms have a wide variety of colors, which depend on their color. There are storms of the following colors:

  • black (chernozem soils of the southern and southeastern regions of the European part of Russia, the Orenburg region and Bashkiria);
  • yellow and brown (typical of the USA and Central Asia- loam and sandy loam);
  • red (red-colored, iron oxide-colored soils of the desert areas of Afghanistan and Iran;
  • white (salt marshes of some regions of Kalmykia, Turkmenistan and the Volga region).

Geography of storms

The occurrence of dust storms occurs in completely different places on the planet. The main habitat are semi-deserts and deserts of tropical and temperate climatic zones, and both hemispheres.

Usually the term "dust storm" is used when it occurs over loamy or clayey soil. When does it occur in sandy deserts(for example, in the Sahara, Kyzylkum, Karakum, etc.), and, in addition to the smallest particles, the wind carries through the air millions of tons and larger particles (sand), the term " sandstorm".

Dust storms often occur in the Balkhash and Aral regions (southern Kazakhstan), in the western part of Kazakhstan, on the Caspian coast, in Karakalpakstan and in Turkmenistan.

Where are dusty Most often they are observed in the Astrakhan and Volgograd regions, in Tyva, Kalmykia, as well as in the Altai and Trans-Baikal Territories.

During periods of prolonged drought, storms can develop (not every year) in the forest-steppe and steppe zones of Chita, Buryatia, Tuva, Novosibirsk, Orenburg, Samara, Voronezh, Rostov regions, Krasnodar, Stavropol Territories, Crimea, etc.

The main sources of dust haze near the Arabian Sea are the peninsulas and the Sahara. Storms from Iran, Pakistan and India bring less damage in these places.

China storms carry dust to the Pacific Ocean.

Ecological consequences of dust storms

The described phenomena are able to move huge dunes and carry large volumes of dust in such a way that the front can be represented as a dense and high wall of dust (up to 1.6 km.). The storms that come from the Sahara desert are known as Samoom, Khamsin (Egypt and Israel) and Khabub (Sudan).

For the most part in the Sahara, storms occur in the Bodele depression and at the junction of the borders of Mali, Mauritania and Algeria.

It should be noted that over the past 60 years, the number of Sahara dust storms has increased by about 10 times, which caused a significant decrease in the thickness of the surface soil layer in Chad, Niger, and Nigeria. For comparison, it can be noted that in Mauritania in the 60s of the last century there were only two dust storms, and today there are 80 storms a year there.

Environmental scientists believe that an irresponsible attitude towards the arid regions of the Earth, in particular, ignoring the crop rotation system, steadily leads to an increase in desert areas and a change in the climatic state of the planet Earth at the global level.

Ways to fight

Dust storms, like many others, cause great harm. In order to reduce and even prevent their negative consequences, it is necessary to analyze the features of the terrain - the relief, the microclimate, the direction of the winds prevailing here, and take appropriate measures that will help reduce the wind speed near the earth's surface and increase the adhesion of soil particles.

To reduce the wind speed, certain measures are taken. Systems of wind-shelter wings and forest belts are being created everywhere. A significant effect to increase the adhesion of soil particles is provided by non-moldboard plowing, abandoned stubble, crops of perennial grasses, strips of perennial grasses interspersed with crops of annual crops.

Some of the most famous sand and dust storms

For example, we offer you a list of the most famous sand and dust storms:

  • In 525 BC. e., according to Herodotus, in the Sahara during a sandstorm, the 50,000th army of the king of Persia Cambyses died.
  • In 1928, in Ukraine, a terrible wind raised more than 15 million tons of black soil from an area equal to 1 million km², the dust of which was transferred to the Carpathians, Romania and Poland, where it settled.
  • In 1983, the strongest storm in the north of Victoria, Australia covered the city of Melbourne.
  • In the summer of 2007, a severe storm occurred in Karachi and in the territories of the provinces of Balochistan and Sindh, and heavy rains that followed her, led to the death of about 200 people.
  • In May 2008, a sandstorm in Mongolia killed 46 people.
  • In September 2015, a terrible "sharav" (sand storm) swept across much of the Middle East and North Africa. Israel, Egypt, Palestine, Lebanon, Jordan, Saudi Arabia and Syria. There were also human casualties.

In conclusion, a little about extraterrestrial dust storms

Martian dust storms occur in the following way. Due to the strong difference in temperature between the ice sheet and warm air at the edge of the southern polar cap of the planet Mars, strong winds arise, raising huge clouds of red-brown dust. And here there are certain consequences. Scientists believe that the dust of Mars can play about the same role as earth clouds. The atmosphere is heated by the absorption of sunlight by dust.

DUSTY (SANDY) DRYING. The transfer of dust, dry earth or sand only at the earth's surface, up to a height of less than 2 m (not higher than the level of the observer's eye).[ ...]

Dust storms - associated with the transfer of a large amount of dust or sand raised from the earth's surface by a strong wind; particles of the top layer of dried soil, not held together by vegetation. They can be caused by both natural (drought, dry winds) and anthropogenic factors (intensive plowing of land, overgrazing, desertification, etc.). Dust storms are characteristic mainly of arid regions (dry steppes, semi-deserts, deserts). However, sometimes dust storms can also be observed in forest-steppe regions. In May 1990, a strong dust storm was observed in the forest-steppes of Southern Siberia (wind speed reached 40 m/s). Visibility decreased to a few meters, power poles overturned, powerful trees turned inside out, fires blazed. In the Irkutsk region, on 190 thousand hectares, plantings of agricultural crops were damaged and died.[ ...]

Dust storms occur during very strong and prolonged winds. The wind speed reaches 20-30 m/s and more. Most often, dust storms are observed in arid regions (dry steppes, semi-deserts, deserts). Dust storms irrevocably carry away the most fertile topsoil; they are able to dispel up to 500 tons of soil from 1 hectare of arable land in a few hours, negatively affect all components of the natural environment, pollute the air, water bodies, and adversely affect human health.[ ...]

DUST STORM - a phenomenon in which strong wind(speed reaches 25-32 m / s) raises a huge amount of solid particles (soil, sand), blown out in places not protected by vegetation and swept into others. P. b. serves as an indicator of improper agricultural practices, neglect of maintaining ecological balance.[ ...]

Dust storms are one of the most dangerous meteorological phenomena for agriculture. They arise under the influence of both natural and anthropogenic factors and are often associated with forms of agriculture that do not correspond to a given climatic zone. Many areas affected by dust storms steppe zone Russia.[ ...]

Dust storms are most often observed in the spring, when the wind increases and the fields are plowed or the vegetation on them is still poorly developed. There are dust storms in the steppes at the end of summer, when the soil dries up, and the fields begin to plow up after harvesting the early spring crops. Winter dust storms are relatively rare.[ ...]

Dust storm- transfer of dust and sand by strong and prolonged winds blowing out the upper layers of soils. A typical phenomenon in plowed steppes, as well as in semi-deserts and deserts of the USA, China and other zones.[ ...]

Dust storms occur mainly in cold period of the year. This most active and dangerous look deflation is facilitated by strong atmospheric pressure drops in vast areas relatively close to each other, low soil moisture, and the absence of snow cover on them.[ ...]

A dust (black) storm is a very strong wind with a speed of more than 25 m/s, carrying a huge amount of solid particles (dust, sand, etc.) blown out in places not protected by vegetation and swept into others. A dust storm, as a rule, is a consequence of disturbing the soil surface by improper agricultural practices: reducing vegetation, destroying the structure, drying out, etc.[ ...]

A storm is a type of hurricane but has a slower wind speed. The main causes of casualties during hurricanes and storms are the defeat of people by flying fragments, falling trees and building elements. The immediate cause of death in many cases is asphyxia from pressure, severe injuries. Among the survivors, there are multiple soft tissue injuries, closed or open fractures, craniocerebral injuries, spinal injuries. Wounds often contain deeply penetrating foreign bodies(soil, pieces of asphalt, glass fragments), which leads to septic complications and even gas gangrene. Dust storms are especially dangerous in the southern arid regions of Siberia and the European part of the country, as they cause erosion and weathering of the soil, removal or backfilling of crops, and exposure of roots.[ ...]

Dust storms at high wind speeds and after a long dry period are a source of innumerable disasters for the entire southeast and south of the USSR. The most destructive storms in the territory under consideration were in 1892, 1928, 1960[ ...]

Dust storms have inflicted huge damage land cover and farming in the southern Great Plains region. They became the last warning to the Americans about the disastrous state of the soil cover of the United States. Therefore, in 1935 on federal level The Soil Protection Service was organized, headed by an outstanding specialist in the field of soil science H. Bennett. A survey conducted during this period showed that nationwide measures were needed to save soil fertility. From 25 to 75% of the topsoil was destroyed on an area of ​​256 million hectares.[ ...]

DUST STORM. Transfer large quantities dust or sand by a strong wind - a typical phenomenon of deserts and steppes. The surface of deserts, free from vegetation and dried up, is a particularly effective source of dust in the atmosphere. The range of visibility during P. B. is significantly reduced. In the plowed steppes, dust storms cover the crops and blow out the top layers of the soil, often along with seeds and young plants. Dust can then fall out of the air in quantities of millions of tons over large areas away (sometimes thousands of kilometers) from the dust source (see dust deposition). P. B. are frequent in the USA, China, the UAR, in the Sahara and Gobi deserts, in the USSR - in the deserts of the Turan lowland, in the Ciscaucasia and in the south of Ukraine.[ ...]

Dust storms are a formidable and dangerous manifestation of wind erosion. It occurs on vast areas of the poorly protected surface of the earth under high-speed winds and causes enormous damage to the national economy and damage to soil fertility that is irreparable and invaluable in money.[ ...]

These dust storms interrupted the normal course of life in cities and on farms, interrupted classes in schools, caused new types of diseases, such as "dust pneumonia" and others, and were an unexpected serious threat to the existence of the population. The area of ​​arable and pasture land subject to wind erosion in the United States in the area of ​​the great plains exceeds 90 million hectares. So sharply affected the consequences of capitalist use natural resources in this country.[ ...]

Dust storms are a meteorological phenomenon in which a strong or moderate wind from the surface of the earth, free from vegetation or having a poorly developed grassy cover, raises dust, sand or small soil particles into the air, worsening visibility in the range from a few meters to 10 km. Dust storms occur during a rainless dry period, often at the same time as dry winds. The distribution of the number of days with dust storms to a large extent depends on the relief. The largest number of days with a dust storm is observed in the central and eastern regions of the territory. Their number per year averages 11-19 days. On the plains of the Western Ciscaucasia, the number of days with dust storms decreases to 1-4 per year. In floodplains, valleys, and hollows, where the soil is turfed and the wind is somewhat weaker, the number of days with dust storms is reduced. In the mountains and Black Sea coast Caucasus south of Novorossiysk, there are no dust storms. Most often, dust storms are observed in summer and spring.[ ...]

In 1969, dust storms were large area in the European part of Russia - in the North Caucasus and the Volga region. In the Stavropol Territory, M.N. Zaslavsky observed areas of arable land where a layer of soil 10–20 cm thick was blown out. During a dust storm in 1969 in the European part of Russia, winter crops died over a huge area, measured by the first million hectares.[ ... ]

With local dust storms in the conditions of Kazakhstan, bo ranges from 50 to 100 m. Therefore, 5 should be 500-1000 m.[ ...]

The frequency of dust storms is most affected by the influence of the underlying surface and the degree of protection of the territory. A necessary condition for dust storms is the presence of dry fine earth, sand, or other weathering products. In such areas, a slight increase in wind (up to 5-6 m/sec) is sufficient for the occurrence of a dust storm. Dust storms are harmful phenomena for grazing and keeping livestock in areas of transhumance.[ ...]

By the time of the dust storm on April 20, early vegetable crops - carrots, onions, sorrel - were sown on part of this site; sowing is rolled with a smooth roller. Part of the unsown area was only harrowed, not rolled. A dust storm from the rolled part of the site carried out a layer of soil 4-5 cm along with seeds, threw it through an adult forest belt. The non-rolled part of the site did not erode. In the soil layer 0-5 cm before the start of the dust storm, there was the following number of aggregates (in %).[ ...]

1.11

In the winter of 1969, strong dust storms were observed due to both meteorological conditions (easterly hurricane winds) and agrotechnical factors. In some areas of the Lower Don, a 2-5 cm soil layer was removed from the surface of arable land with crops, and: in the Stavropol Territory - a soil layer of up to 6-8 cm or more. Powerful snow-earth ramparts (up to 25 m wide and more, with a height of up to 2 m) formed near the forest belts. Winter crops were damaged in Rostov region And Krasnodar Territory respectively on the area of ​​646 and 600 thousand hectares. However, winter crops and irrigation canals protected by forest belts, especially in the meridional direction, suffered much less than in other areas. It has been established that the main ways to protect soils in the steppe regions from dust storms are agroforestry and a high level of agrotechnical work.[ ...]

Frontal dust storms are shorter (up to 6-8 hours), while dust storms in storm zones can last more than a day.[ ...]

UV - maximum speed wind (at the height of the weather vane) during dust storms with a probability of 20% (see Table 9.3), m/s; th - field surface roughness parameter, m.[ ...]

The enormous significance of this phenomenon can already be judged by the fact that after the dust storms in 1969 in the Don and Kuban, the height of dust shafts deposited on mechanical barriers in the Krasnodar Territory sometimes reached 5 m. Since the beginning of the formation of the considered barriers are often trees and bushes, it's hard to exaggerate positive role(especially with the development of agriculture on large areas) forest belts.[ ...]

In 1957, V. A. Francesoia and co-workers published data on observations of dust storms on ordinary chernozems of the Kustanai region (Franceson, 1963). The authors took a layer from 0 to 3 cm from fields with different erosion states and subjected them to structural analysis. As a result, it was concluded that the wind resistance of the soil surface is ensured with a content of 40% of lumps larger than 2 mm in diameter, including lumps larger than 10 mm from 10 to 25%¡. They also noted a high content of aggregates smaller than 1 mm in diameter in the surface layer of eroding fields. The choice of soil-protective clods larger than 2 mm in diameter as an indicator of the wind resistance of the soil surface is not justified by any research. According to the structural analysis data available in the work, we divided the fractions into two groups - larger and smaller than 1 mm, and calculated the clodiness indices for fields subjected to and not subjected to erosion (Table 5).[ ...]

Naturally, the atmosphere is polluted during volcanic eruptions, forest fires, dust storms, etc. At the same time, solid and gaseous substances enter the atmosphere, which are classified as non-permanent, variable components of atmospheric air.[ ...]

In Chapter 1, we discussed the role of dust emissions from industrial plants, thermal power plants, dust storms and other sources of tiny particulate matter, dust released into the atmosphere as a result of human activities, in air pollution. The contribution of technogenic dusting of the atmosphere to albedo changes can be twofold. On the one hand, a decrease in the transparency of the atmosphere increases the reflection and scattering of solar radiation in space. At the same time, dusting of mountain glaciers and snow-covered surfaces reduces their reflectivity and accelerates melting.[ ...]

Protective forest strips - planting trees and shrubs in the form of a series of strips, designed to protect farmland, gardens from dry winds, dust storms, wind erosion, to improve water regime soils, as well as to preserve and maintain the species diversity of agrocenoses (restrains mass reproduction of pests), etc. Especially important role forest belts play in the protection of grain crops during dust storms in arid regions of the country. In 1994, field-protective forest belts were created in Russia on an area of ​​7.2 thousand hectares, and pasture plantations - on an area of ​​28.4 thousand hectares.[ ...]

The eolian sediments from the indicated parts of the field, which were deposited near various kinds of obstacles, contained 88.4%: aggregates smaller than 1 mm in diameter and only 11.6% soil-protective. Fine earth collected during two dust storms in dust collectors consisted of 96.9% erosion-hazardous soil fractions, with the most aggressive fractions (less than 0.5 mm in diameter) accounting for 81.6%.[ ...]

The task is to place obstacles on the path of the flow precisely at such distances at which the content of fine earth in the flow does not exceed the permissible value, and then the occurrence of a dust storm will be excluded.[ ...]

Aerosols (from Greek - air and German - colloidal solution) - solid or liquid particles suspended in a gaseous medium (atmosphere). Their sources are both natural (volcanic eruptions, dust storms, forest fires, etc.) and anthropogenic factors (thermal power plants, industrial enterprises, concentrating plants, agriculture, etc.). Thus, in 1990, the emission of solid particles (dust) into the atmosphere in the world amounted to 57 million tons. Especially a lot of technogenic dust is formed during the combustion of hard or brown coal at thermal power plants, in the production of cement, mineral fertilizers, etc. Based on the study of the content suspended particles in the atmosphere at 100 global monitoring stations (for the period 1976-1985), it was found that the most polluted cities are Calcutta, Bombay, Shanghai, Chicago, Athens, etc. These artificial aerosols cause a number of negative phenomena in the atmosphere (photochemical smog, decrease in the transparency of the atmosphere, etc.), which is especially harmful to the health of urban residents.[ ...]

The criteria for assessing green areas in various natural and climatic regions of the country are also ambiguous. So, for example, specific requirements (respectively, assessment methods) are imposed in the forest-steppe and steppe zones - protection from dust storms and dry winds, soil stabilization, etc. growth, etc. Of course, no less important are the differences in the role that green spaces play in shaping the architectural and artistic appearance of the city.[ ...]

Under certain conditions, all components general circulation atmosphere can be accompanied by the phenomenon of wind erosion of soils, which leads to dusting of the atmosphere. In meteorology, the phenomenon of the transfer of soil particles by a strong wind is called a dust storm. The horizontal extent of a dust storm is from tens and hundreds of meters to several thousand kilometers, and the vertical extent is from several meters to several kilometers.[ ...]

Of the characteristics of the water regime, the most important are the average annual precipitation, their fluctuation, seasonal distribution, moisture coefficient or hydrothermal coefficient, the presence of dry periods, their duration and frequency, frequency, depth, the time of establishment and destruction of snow cover, seasonal dynamics of air humidity, the presence dry winds, dust storms and other favorable natural phenomena.[ ...]

Quarantine weeds spread with seeds cultivated plants, which is facilitated by the movement of large volumes of seed, food and fodder grains within the country and from abroad. The most common sources of quarantine weeds are non-agricultural areas, roads, irrigation and drainage systems, winds, dust storms, etc.[ ...]

The studies were carried out in island plantations of pine in the Minusinsk and Shirinsk steppes, of which the latter is characterized by a severe climate (Fig. 1). The Shirinskaya steppe of Khakassia is characterized by unstable atmospheric moisture with fluctuations in annual precipitation from 139 to 462 mm, as well as a very uneven distribution over the seasons. Constant and rather strong winds lead to dust storms in the winter-spring period, about 30-40 days a year the wind speed reaches 15-28 m/s (“Formation and properties...”, 1967). The average annual amount of moisture evaporating from the water surface (for Khakassia it is 644 mm) is almost twice the annual amount of precipitation. There are 29 days in a year from relative humidity air about 30%. The greatest dryness of air and soil is observed in spring and early summer (Polezhaeva, Savin, 1974).[ ...]

Dust rising from the surface of the earth consists of small particles rocks, soil residues of vegetation and living organisms. The sizes of dust-like particles, depending on their origin, range from 1 to several microns. At a height of 1-2 km from the earth's surface, the content of dust particles in the air ranges from 0.002 to 0.02 g/m3, in some cases this concentration can increase tens and hundreds of times, during dust storms up to 100 g/m' and more .[ ...]

The wind speed naturally changes during the day, along with it, the intensity of the processes of wind erosion of soils also changes. Obviously, the longer the wind, which has a speed greater than the critical one, the greater will be the loss of soil. Typically, the wind speed increases during the day, reaching a maximum by noon, and decreases in the evening. However, it is not uncommon for the intensity of wind erosion to vary slightly during the day. So, in the spring of 1969 in the Krasnodar Territory, the strongest dust storms continuously lasted 80-90 hours, and in February of the same year - up to 200-300 hours.[ ...]

Winds of the southern, southwestern and northern directions prevail (Table 1.7). The percentage of days with calm on average is 17-19 with maxima in December-March and August. The average annual wind speed is 3.2-4.3 m/s (Table 1.8) and has a well-defined daily course, determined primarily by the daily variation of air temperature (Table 1.9). Daily fluctuations are more pronounced in the warm period and less in winter and early spring. The maximum wind speed is observed in winter. The average number of days with strong winds is 27-36 (Table 1.10), and the number of days with dust storms does not exceed 1.0 (Table 1.11).[ ...]

Let us give some examples of insulation overlaps that have taken place in recent years both with natural and industrial pollution. In the winter of 1968-69 in the south of the European part of the Soviet Union there were massive insulation surges. At the same time, in one power system, within a few days, 57 overlaps occurred only on 220 kV overhead lines with normal insulation, as a result of which the power supply to consumers along these lines was interrupted. The reason for the overlaps is the contamination of the insulators with soil dust with a high salt content during a dust storm and subsequent moistening with thick fog and drizzling rain with an increase in temperature and humidity of the atmospheric air. At the open switchgear of a thermal power plant located in the northwestern part of the Soviet Union and operating on shale fuel, insulation of normal execution was applied. Under unfavorable meteorological conditions, insulation flashovers were repeatedly observed at this station in normal operating conditions. In the winter of 1966, after a long frosty period, a sharp warming set in, as a result of which there were overlaps of 220 kV disconnectors assembled from support-rod insulators of the KO-400 C type. The consequences of this overlap are a large undersupply of electricity and a violation of the stability of the power system. One can also point to a number of overlaps that have taken place in recent years near chemical industry plants in various regions of the Soviet Union under unfavorable meteorological conditions and when a torch of emissions hit the insulators. For example, during heavy fog and light wind from the side of a large petrochemical plant, external insulation overlaps were observed at distances up to 10 km from the pollution source. Similar overlaps with consequences of an emergency nature have been repeatedly observed abroad.[ ...]

Earth atmosphere is a mechanical mixture of gases, called air, with solid and liquid particles suspended in it. For a quantitative description of the state of the atmosphere at certain points in time, a number of quantities are introduced, which are called meteorological quantities: temperature, pressure, air density and humidity, wind speed, etc. In addition, the concept of an atmospheric phenomenon is introduced, which means physical process, accompanied by a sharp (qualitative) change in the state of the atmosphere. Atmospheric phenomena include: precipitation, clouds, fog, thunderstorms, dust storms, etc. The physical state of the atmosphere, characterized by a combination of meteorological quantities and atmospheric phenomena, is called weather. For analysis and prediction of the weather on geographic Maps apply by conventional signs and numbers the values ​​of meteorological quantities, as well as special weather phenomena, determined at a single point in time at an extensive network of meteorological stations. Such maps are called weather maps. The statistical long-term weather regime is called climate.[ ...]

Irrigation erosion is a kind of water erosion. It develops as a result of violation of the rules of irrigation in irrigated agriculture. Waving of the upper horizons of the soil under the influence strong winds called wind erosion, or deflation. During deflation, the soil loses the smallest particles, with which the most important for fertility are taken out. chemical substances. The development of wind erosion is facilitated by the destruction of vegetation in areas with insufficient atmospheric moisture, excessive grazing, and strong winds. It is most susceptible to sandy and fertile carbonate chernozems. During strong storms, soil particles can be carried away over considerable distances from large areas. According to M. L. Iackson (1973), annually up to 500 million tons of dust enters the atmosphere on the planet. It is known from history that dust storms destroyed the unprotected soils of the vast agricultural territories of Asia, Southern Europe, Africa, South and North America, Australia. They are now becoming a national or regional scourge in many states. Soil losses from wind erosion in the most catastrophic years are up to 400 t/ha. In the USA in 1934, as a result of a storm that broke out in the region of the plowed prairies of the Great Plain, about 20 million hectares of arable land were turned into waste land, and 60 million hectares sharply reduced their fertility. According to R. P. Beasley (1973), in the 30s in this country there were more than 3 million hectares (about 775 million acres) of highly eroded lands, in the mid-60s their area slightly decreased (738 million acres), and in the 1970s it increased again. In pursuit of a profit from the sale of grain, pastures and grassed slopes were plowed up. And this immediately affected the stability of soils from dispersal. Yield losses on such soils today are 50-60%. Similar phenomena are found everywhere.[ ...]

Since 1963, the PAU-2 aerodynamic installation has been used to study erosion processes. This device made it possible to experimentally study the processes of soil erosion by wind. The principle of operation of the device is as follows: over a limited area of ​​the soil surface (in a field or on a stationary site above an artificially created site with specified roughness parameters), an artificial air flow similar to natural wind is created; when the air flow moves over the area of ​​the soil surface, the blowing and transfer of soil material occurs, which is also similar to the natural erosion of soil by wind during dust storms; part of the fine earth carried by the air flow is captured by dust collectors installed at various heights above the soil surface and deposited in cyclones. According to the amount of soil material captured by PAH-2 from the surface of the site during the experiment, the erodibility of this soil is judged (Bocharov, 1963).[ ...]

A typical desert aerosol consists of 75% clay minerals (35% montmorillonite and 20% kaolinite and illite each), 10% calcite, and 5% each quartz, potassium nitrate, and iron compounds limonite, hematite, and magnetite, mixed with some organic substances. . According to line 1a of Table. 7.1, the annual production of mineral dust varies widely (0.12-2.00 Gt). With height, the concentration decreases, so that mineral dust is observed mainly in the lower half of the troposphere up to heights of 3-5 km, and above areas of dust storms - sometimes up to 5-7 km. In the size distribution of mineral dust particles, there are usually two maxima in the ranges of coarse (mainly silicate) fraction g = 1 ... 10 μm, which significantly affects the transfer thermal radiation, and submicron fraction r[ ...]

As with all natural processes, there is a mutual relationship between natural disasters. One catastrophe has an impact on another, it happens that the first catastrophe serves as a trigger for subsequent ones. The genetic dependence of natural disasters is shown in fig. 2.4, arrows show the direction of natural processes: the thicker the arrow, the more obvious this dependence. The closest relationship exists between earthquakes and tsunamis. Tropical cyclones almost always cause flooding; earthquakes can cause landslides. Those, in turn, provoke floods. There is a mutual relationship between earthquakes and volcanic eruptions: earthquakes caused by volcanic eruptions are known, and vice versa, volcanic eruptions caused by earthquakes. Atmospheric disturbances and heavy rainfall can affect slope creep. Dust storms are a direct consequence of atmospheric disturbances.[ ...]

An admixture of clastic material is represented by feldspars, pyroxenes, and quartz. Feldspar, pyroxenes, and montmorillonite come from intra-oceanic sources, and the latter in particular comes from underwater decomposition of basalts. Terrigenous chlorite comes from areas with the development of rocks of low stages of metamorphism. Quartz, illite, and, to a lesser extent, kaolinite are carried into the ocean, as is assumed, by high-altitude atmospheric jet streams; the contribution of eolian material to the composition of pelagic clays is probably from 10 to 30%. A well-studied supplier of clay matter to the deep-water basins of the Atlantic is the Sahara desert - the material of dust storms in Africa can be traced back to caribbean. The eolian clays of the Indian and North Pacific Oceans were probably formed due to the removal of dust from the Asian mainland; Australia is the source of eolian material in the South Pacific.[ ...]

Soil erosion is another factor disturbing the soil cover. This is the process of destruction and demolition of soils and loose rocks by water flows and wind (water and wind erosion). Human activity accelerates this process in comparison with natural phenomena by 100-1000 times. Over the last century alone, more than 2 billion hectares of fertile agricultural land, or 27% of agricultural land, has been lost. Erosion carries away with water and soil biogenic elements (P, K, 14, Ca, Mg) in quantities much greater than those applied with fertilizers. The structure of the soil is destroyed, and its productivity is reduced by 35-70%. The main cause of erosion is improper land cultivation (during plowing, sowing, weeding, harvesting, etc.), leading to loosening and grinding of the soil layer. Water erosion prevails in places of intense rains and when using sprinkling installations in places of slopes of field surfaces, saddles. Wind erosion is typical for areas with elevated temperatures, insufficient moisture, combined with strong winds. So, dust storms carry away up to 20 cm of the soil layer along with crops.

Huge, swirling reddish clouds of sand and dust, raised from the surface of the earth by dry, hot and fast air currents, carry death. So, in 1805, a dust storm completely covered a caravan of two thousand people and the same number of camels with sand. The same story befell the Sahara in 525 BC. the legendary army of the Persian ruler Cambyses II: a terrible sandstorm stopped the military expedition halfway, killing about fifty thousand soldiers.

A sure sign that a sandstorm is approaching is a sudden silence when the wind stops blowing, and with it all sounds and rustles disappear. Instead, stuffiness intensifies, and along with it, anxiety emerges at a subconscious level. And after a while, a fast-growing black-purple cloud appears on the horizon. The wind appears again and, picking up speed, raises dust and sand.

A sandstorm, or as it is also called, a dust storm is an atmospheric phenomenon when a strong wind moves a huge amount of grains of sand, soil particles or dust over long distances. The height of such a cloud can exceed a kilometer, while the visibility inside it decreases to several tens of meters.

As these particles settle, the ground becomes reddish, yellowish or greyish (depending on the composition of the airborne particles). Despite the fact that dust storms appear mainly in summer, in the absence of precipitation and rapid drying of the soil, they also occur in winter.

Dust storms form mainly in desert or semi-desert regions (the Sahara desert is especially famous for them), but sometimes due to drought it can also occur in the forest-steppe and forest regions of the planet. So, in April 2015, Khmelnytsky, a city located in western Ukraine, was hit by a sandstorm. The hurricane lasted about five minutes, visibility did not exceed ten meters, and the wind was so strong that it almost carried people and vehicles off the bridges.

How a storm is formed

In order for a dust storm to arise, a dry ground surface and a wind speed exceeding 10 m / s are required (for example, in the Sahara, its rates often reach 50 m / s). Dust storms appear due to the turbulence (heterogeneity) of air flows, which, when moving over an uneven surface, collide with obstacles, form air turbulences. The faster the wind moves, the more dangerous eddies it creates.

After the movement increases air masses above loose soil particles, the adhesion between which is weakened due to the dryness of the soil (which is why storms of this type appear mainly in deserts), the grains of sand begin to vibrate, then jump, and as a result of repeated impacts turn into fine dust.

Air swirls easily lift sand or dust particles from the ground, while the temperature of the lower layers of air masses rises greatly: over the steppes - up to 1.5 km, over deserts - up to 2.5 km. After that, air is mixed with dust particles, which tend to be distributed over the entire area of ​​the heated air.

Whereas smaller particles earth's surface fly extremely high, large ones rise to a lower distance and fall quickly (if the wind is extremely strong, the dust can be transported thousands of kilometers). The strength of the wind during sandstorms is such that it is quite capable of moving the dunes, and the sand raised by it will be like a huge cloud one and a half kilometers high.

In order for a dust storm to form, the soil must be dry: in the event of a prolonged drought under the influence of strong winds, even particles of the upper layers of black earth soil can rise into the air (in this case, a “black storm” is formed) and move long distances.

So, at the end of the twenties of the last century in the forest-steppe and steppe forests of Ukraine, a dust storm suddenly appeared, lifted up more than 15 million tons of black soil (the height of the cloud was 750 m) and moved them thousands of kilometers to the side. Some of the dust settled in the Carpathians, Poland and Romania, as a result of which the fertile soil layer in the affected regions (about 1 million km2) decreased by 10-15 cm.

How long does the event last

Sandstorms typically last from thirty minutes to four hours. At the same time, short-term dust storms are characterized by a slight deterioration in visibility: the terrain is visible up to four, and sometimes up to 10 kilometers.

Among short-term dust storms, there are also such dust storms during which visibility is limited to two tens of meters.

A dust storm always appears almost unexpectedly: in good weather, a heavy wind will rise, as a result of which the speed of air flows increases, picking up and lifting dust particles into the air.

True, poor visibility does not last long, even though the wind speed is increasing at this time. You can tell that a dust storm is approaching by the gray foggy veil that appears under cumulonimbus clouds when they are close to the horizon.

There are also long sandstorms:

  • Some dust storms are characterized by only a partial deterioration in visibility, up to four kilometers (however, these dust storms are the longest in time, since they can last several days).
  • Others are characterized by limited visibility to a few meters on initial stage development, after which it clears up to one kilometer. But these sandstorms last no more than four hours.


Storms of the Sahara

Many sandstorms originate in the world's largest desert, the Sahara, where Mauritania, Mali and Algeria border each other. Over the past half century, the number of sandstorms in the Sahara has increased tenfold (about eighty storms sweep through Mauritania alone in a year).

The uplifted sand of the Sahara is so abundant that a huge amount of sand particles are transported through Atlantic Ocean. This situation is possible due to the fact that when dust and sand move over the desert, they continue to heat up along with the air, after which, once above the ocean, they pass under a colder and more humid air stream. The difference in temperature between the layers of air causes them to not mix with each other, allowing dusty warm air to cross the ocean.

Despite the fact that sandstorms cause many negative consequences (destroy the fertile soil layer, adversely affect respiratory system living organisms), the dust raised into the air also brings benefits. For example, dust storms in the Sahara supply humid equatorial forests Central and South America a huge amount of mineral fertilizers, and the ocean receives the missing part of the iron. At the same time, the dust raised in Hawaii makes it possible for banana trees to grow.

What to do if caught in a storm

Having noticed the first signs of an approaching storm, you need to stop immediately: it is useless to continue moving and an extra waste of energy, especially since a sandstorm rarely lasts more than four hours. Even if the wind does not subside for about two or three days, it is better to wait in one place and not go anywhere. Therefore, all supplies of water and food must be kept near you (especially water, otherwise complete dehydration of the body is ensured, and this always leads to death).

Stopping, you need to immediately start looking for shelter. It can be a large stone, a boulder, a tree near which you need to lie down on the leeward side and completely, with your head, wrap yourself in matter. If it is possible to hide in a car, it must be placed in such a way that the wind does not blow through the door.

In the worst case, if there is no shelter nearby, you need to lie on the ground and cover your head with clothes (the Bedouins in such cases dig something like a trench). It should be borne in mind that when a sandstorm passes, the air temperature at that moment will be about fifty degrees, which can lead to loss of consciousness. Breathe while tons of sand are sweeping over your head, you only need to use a handkerchief, otherwise the smallest particles will enter the respiratory tract.

Sand (dust) storm is the transport of vast quantities of soil particles, such as sand and dust, in the atmosphere. At the same time, there is a significant deterioration in line of sight (usually, at the level of 2 meters from the ground, it is 1 km, in rare cases it can change to several hundred and even tens of meters). From the outside, the storm looks like a dense wall with a height of several hundred meters.

Sandstorms occur with strong air currents, the speed of which is more than 10 m / s, it depends on the type and moisture content of the soil. In desert and semi-desert areas, this atmospheric phenomenon is observed especially often.

To suppress a sandstorm, a variety of means are used that create physical resistance that prevents its further spread. Forests serve as a natural barrier of this kind; this is perhaps the most effective and cheapest means. Water and snow retention facilities are also used.

In addition to the negative effects of sand and dust storms, such as:

  • Impact on the respiratory system of animals.
  • Significant deterioration in line of sight affecting air and motor vehicles
  • Destruction or temporary deterioration of fertile soil layers.
  • damage to young plants.
  • And so on…

they can also be useful:

  • Normalization of the climate of high-moisture tropical forests.
  • Compensation for the lack of iron in the ocean.
  • Dust promotes the growth of banana crops.
  • And so on…

Interesting information about extraterrestrial dust storms, namely on Mars from Wikipedia:

The strong temperature difference between the ice sheet and the warm air at the edge of Mars' south polar cap creates strong winds that kick up huge clouds of red-brown dust. Experts believe that dust on Mars can play the same function as clouds on Earth - it absorbs sunlight and heats up the atmosphere.

Video recordings of sandstorms

Amazing video footage of a sandstorm driving directly into its very epicenter.

Shooting a sandstorm at some military base. A mixture of air and sand covers the entire area until it is completely hidden from sunlight.

Another video recording, but from the window of a high-rise building.

And finally, the brightest and most amazing photos of dust and sand storms.

The strongest sandstorm on Mars.

Satellite photos of sandstorms in Australia:

Photos of sandstorms in Australia, but from the ground:

Sandstorms - samums - have long been covered with a gloomy halo. It is not for nothing that they bear this name - “samum” means poisonous, poisoned. And such storms really ruined entire caravans.
Samum is observed in the deserts of North Africa and the Arabian Peninsula and most often has a western and southwestern direction. It mostly happens in spring and summer.

“An hour or half an hour before the merciless storm rises, bright sun dim, clouded over with a muddy veil. A small dark cloud appears on the horizon. It grows rapidly, covering the blue sky. Here came the first furious gust of hot, prickly wind. And in a minute the day fades. Clouds of burning sand mercilessly cut through all living things, cover the midday sun. In the howl and whistle of the wind, all other sounds disappear. It seems that the air itself is turning against you ... ”- This is the description of a sandstorm given by the ancient Greek historian Herodotus

Nowadays, when the desert is crossed by highways, and air routes run above them in all directions, death on the great caravan routes no longer threatens travelers.

So, in 1805, samum, according to many authors, covered two thousand people and one thousand eight hundred camels with sand. And it is quite possible that the same storm killed in 525 BC. the army of the Persian king Cambyses, about which Herodotus wrote

It happens that the testimonies of people who have endured the test of the elements sin with exaggerations. However, of course - the samum is very dangerous.

Fine sandy dust, which is raised by a strong wind, penetrates into the ears, eyes, nasopharynx, lungs

Saving lives, people lie down on the ground and tightly cover their heads with clothes. It happens that from suffocation and high temperature, often reaching fifty degrees, they lose consciousness.

Many desert storms owe their birth to passing cyclones that affect deserts as well. There is another reason - in the deserts during the hot season decreases Atmosphere pressure. Hot sands strongly heat the air near the surface of the earth. As a result, it rises, and streams of colder dense air rush in its place at very high speeds. Small local cyclones form, giving rise to sandstorms.

According to environmentalists, sandstorms have been ten times more frequent in recent years than they were fifty years ago ... Only in Mauritania, which experienced no more than two sandstorms a year in the early sixties, now there are more than eighty ...