Desert storm. What disasters can a sandstorm lead to? Hurricane winds often lead to storms

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 of air masses over loose particles of soil increases, 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 above the earth's surface fly extremely high, larger 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 chernozem 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).
• For others, visibility is limited to a few meters at the initial stage of 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 across the 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 have 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.

Lots of dust and sand particles. Distributed in deserts, semi-deserts, arable steppes, where strong winds blow.

1. General description

Dust storms are complex atmospheric phenomena characterized by the transport of dust and sand by strong and sustained winds that destroy the soil surface. Dust storms, according to the color and composition of the dust that is transferred, are: black (chernozems), brown and yellow (loam, sandy loam), red (loams with an admixture of iron oxides) and white (salt marshes). Very often there are short-term black storms lasting up to one hour, a large number of them can also last from 10 to 12 hours, and relatively rarely such storms last more than a day. Red storms last longer - for several days. The height of dust rise can reach 2-3 km, but most often - 1-1.5 km. In the winter-spring period, snow and dust storms are observed in the central and southern regions of Ukraine

2. Where and when do they occur

Dust storms occur in deserts, semi-deserts and steppe regions, where there is uncovered soil. Dust storms can carry millions of tons of dust over hundreds and even thousands of kilometers. The destructive effect of a dust storm occurs additionally through the action of soil particles that move at high speed.

Dust storms usually occur in summer, sometimes in spring or winter when there is no snow. In the steppe zone, they also arise during the irrational plowing of the land.

3. Actions in a dust storm

A person who has fallen into a dust storm needs to lie on the leeward side on any tall object that is firmly held on the ground - a stone, a thick bush like that. Airways must be protected with a cloth bandage from sand and dust. Next to you, under your arm, put a closed container with a supply of water.

4. In Ukraine

In February 1951, violent storms at a speed of 16-18 m / s. They blew off the thin snow cover and began to blow out the bare soil. The snow, together with the blown soil, created many obstacles, forming black snowdrifts up to 1-1.5 meters high. Blowing out the soil and winter crops continued in spring months.

Now dust storms temporarily occur in the south of Ukraine. First of all in

Dust (sand) storm - in the form of the transfer of large amounts of dust (soil particles, grains of sand) by wind from the earth's surface in a layer several meters high with a noticeable deterioration (usually at the level of 2 m it is from 1 to 9 km, but in some cases it can decrease to several hundred and even up to several tens of meters). At the same time, dust (sand) rises into the air and at the same time dust settles on large area. Depending on the color of the soil in a given region, distant objects take on a grayish, yellowish, or reddish hue. It usually occurs when the soil surface is dry and the wind speed is 10 m/s or more.

Often occurs in warm time years in and regions. When a certain threshold of wind speed is exceeded (depending on the mechanical composition of the soil and its moisture content), particles and are detached from the surface and are transported through and, causing soil erosion.

Dusty (sandy) drifting snow - the transfer of dust (soil particles, grains of sand) by wind from the earth's surface in a layer 0.5-2 m high, which does not lead to a noticeable deterioration in visibility (if there are no other atmospheric phenomena, horizontal visibility at the level of 2 m is 10 km or more). It usually occurs when the soil surface is dry and the wind speed is 6-9 m/s or more.

Geography

The main distribution area of ​​dust storms is and temperate and tropical climatic zones both hemispheres of the earth.

Desert and deserts are the main sources of airborne dust in the area , make a smaller contribution, and . Dust storms in China carry dust to . Ecologists believe that the irresponsible management of the arid regions of the Earth, such as ignoring the system, lead to and climate change at the local and global levels.

Term "sandstorm", usually used in the sense sandstorms, especially in the Sahara, when in addition to small particles that reduce visibility, the wind also carries millions of tons of larger sand particles above the surface. Term dust storm refers more to the phenomenon of the transport of small particles over distances of up to several thousand km, especially when storms "cover" urban areas.

A high frequency of dust storms is observed in and (south), on the coasts, in , in Karakalpakstan and Turkmenistan. In Russia, dust storms are most often observed in, in the east and in .

During long periods of dry weather, dust storms can develop (not annually) in the steppe and forest-steppe zones: in Russia - in, , Tove, , , , , regions, Bashkiria,, , , regions, and edge; on - in , , , , areas, in ; in northern, central and eastern .

At (before a thunderstorm and heavy rain) short-term (from several minutes to an hour) local dust storms can be observed in summer even at points located in the forest vegetation zone- incl. in and (1-3 days per summer).

Causes

With an increase in the strength of the wind flow passing over loose particles, the latter begin to vibrate and then “jump”. When repeatedly hitting the ground, these particles create fine dust that rises as a suspension.

A recent study suggests that the initial grains of sand with the help of friction induces . The bouncing particles acquire a negative charge, which releases even more particles. Such a process captures twice as many particles as previous theories predict.Particles are released mainly due to and wind. Fronts of gusts of wind can appear due to cooling of the air after a strong with rain or may be dry . After the passage of a dry cold front instability can create a dust storm. In desert areas, dust and sandstorms are most often caused by thunderstorm outputs and increased wind speeds. The vertical dimensions of the storm are determined by the stability of the atmosphere and the weight of the particles. In some cases, dust and sandstorms can be limited to a relatively thin layer due to the effect of temperature inversion. In other cases, dust can rise to a height of 6100 m.

Ways to fight

To prevent and reduce the effects of dust storms, forest shelter belts, snow and water retention complexes are created, and agrotechnical methods are used, such as grass sowing, and contour plowing.

Environmental consequences

Sandstorms can move entire and transport huge volumes of dust, so that the storm front can look like a dense wall 1.6 km high. Dust and sand storms coming from the desert also known as, (in Egypt and ) and (in ).

Most dust storms originate in the Sahara, especially in the and in the area of ​​convergence of boundaries, and . Over the past half century (since the 1950s), dust storms in the Sahara have increased by about 10 times, causing a decrease in the thickness of the topsoil in, Chad, northern and . In the 1960s, only two dust storms occurred in Mauritania, currently there are 80 storms per year. The amount of dust blown out of the Sahara towards the Atlantic Ocean in June five times more than a year ago, which could cool the waters of the Atlantic and reduce activity slightly .

Economic implications

The main damage caused by dust storms is the destruction of the fertile soil layer, which reduces its . In addition, the abrasive effect damages young plants. Other possible negative effects include: reduced affecting air and motor transport; a decrease in the amount of sunlight reaching the Earth's surface; the effect of a thermal "spread"; adverse effects on the respiratory system of living organisms.

Dust can also be of benefit in places of deposition - and receives most of its mineral fertilizers from the Sahara, replenishes the lack of iron in the ocean, dust on helps grow cultures. In northern China and the western United States, soils with deposits of ancient storms, called , are very fertile, but are also a source of modern dust storms when soil-binding vegetation is disrupted.

extraterrestrial dust storms

The strong difference in temperature between the ice sheet and the warm air at the edge of the south polar cap of Mars leads to the emergence of strong winds that raise 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.

Dust storm is a kind of dry wind, characterized by strong winds, carrying huge masses of soil and sand particles over long distances. dusty or sandstorms fall asleep agricultural land, buildings, structures, roads, etc. with a layer of dust and sand, reaching several tens of centimeters. At the same time, the area on which dust or sand falls can reach hundreds of thousands, and sometimes millions of square kilometers.

At the height of a dust storm, the air is so saturated with dust that visibility is limited to three to four meters. After such a storm, often where the shoots were green, the desert spreads. Sandstorms are not uncommon in the vast expanses of the Sahara, the greatest desert peace. Vast desert regions, where sandstorms also occur, are in Arabia, Iran, Central Asia, Australia, South America and in other parts of the world. Sandy dust, raised high into the air, makes it difficult for aircraft to fly, covers the decks of ships, houses and fields, roads, airfields with a thin layer. Falling on the water of the ocean, the dust sinks into its depths and is deposited on the ocean floor.

Dust storms not only raise huge masses of sand and dust into the troposphere - the most "restless" part of the atmosphere, where strong winds constantly blow at different heights (the upper limit of the troposphere in the equatorial zone is at altitudes of about 15-18 km, and in middle latitudes - 8 –11 km). They move colossal masses of sand around the Earth, which can flow like water under the influence of the wind. Encountering small obstacles in its path, the sand forms majestic hills called dunes and dunes. They have a wide variety of shapes and heights. Dunes are known in the Sahara desert, the height of which reaches 200–300 m. These giant waves of sand actually move several hundred meters a year, slowly but steadily advancing on oases, filling up palm groves, wells, and settlements.

In Russia, the northern border of the distribution of dust storms passes through Saratov, Ufa, Orenburg and the foothills of Altai.

whirling storms are complex vortex formations caused by cyclonic activity and spreading over large areas.

stream storms These are local phenomena of small distribution. They are peculiar, sharply isolated and inferior in their significance to eddy storms. whirling storms subdivided into dusty, dustless, snowy and squall (or squalls). Dust storms are characterized by the fact that the air flow of such storms is saturated with dust and sand (usually at a height of up to several hundred meters, sometimes up to 2 km in large dust storms). In dustless storms, due to the absence of dust, the air remains clean. Depending on the path of their movement, dustless storms can turn into dusty ones (when an air flow moves, for example, over desert areas). In winter, whirlwinds often turn into snowstorms. In Russia, such storms are called blizzard, snowstorm, snowstorm.

The features of squall storms are rapid, almost sudden, formation, extremely short activity (several minutes), a quick end, and often a significant destructive force. For example, within 10 minutes the wind speed may increase from 3 m/s to 31 m/s.

stream storms divided into stock and jet. During katabatic storms, the air flow moves down the slope from top to bottom. Jet storms are characterized by the fact that the air flow moves horizontally or even up the slope. stock storms formed by the flow of air from the peaks and ridges of mountains down into the valley or to the seashore. Often in a given locality characteristic of them, they have their own local names(for example, Novorossiysk pine forest, Balkhash pine forest, Sarma, Garmsil). jet storms characteristic of natural corridors, passages between chains of mountains connecting different valleys. They also often have their own local names (for example, Nord, Ulan, Santash, Ibe, Ursatievsky wind).

The transparency of the atmosphere largely depends on the percentage of aerosols in it (the concept of "aerosol" in this case includes dust, smoke, fog). An increase in the content of aerosols in the atmosphere reduces the amount of solar energy coming to the Earth's surface. As a result, the Earth's surface may cool. And this will cause a decrease in the average planetary temperature and the possibility, ultimately, of the beginning of a new ice age.

The deterioration of the transparency of the atmosphere contributes to the creation of interference with the movement of aviation, shipping and other modes of transport and is often the cause of large transport emergencies. Air pollution with dust has a harmful effect on living organisms and vegetable world, accelerates the destruction of metal structures, buildings, structures and has a number of other negative consequences.

Dust contains solid aerosols, which are formed during the weathering of the earth's rock, forest fires, volcanic eruptions and others natural phenomena; solid aerosols industrial emissions and cosmic dust, as well as particles in the atmosphere formed during the crushing process during explosions.

By origin, dust is divided into space, marine, volcanic, ash and industrial. The constant amount of cosmic dust is less than 1% of the total dust content in the atmosphere. In the formation of dust of marine origin, the seas can participate only through the deposition of salts. In a noticeable form, this manifests itself occasionally and at a small distance from the coast. Dust of volcanic origin is one of the most significant air pollutants. fly ash It is formed due to the weathering of the earth's rock, as well as during dust storms.

industrial dust is one of the main constituents of air. Its content in the air is determined by the development of industry and transport and has a pronounced upward trend. Already now, in many cities of the world, a dangerous situation has been created due to the dustiness of the atmosphere due to industrial emissions.

Kurumy

Kurumy Outwardly, they are placers of coarse clastic material in the form of stone mantles and streams on mountain slopes with a steepness less than the angle of repose of coarse clastic material (from 3 to 35–40°). There are a lot of morphological varieties of kurums, which is connected with the nature of their formation. Their common feature is the nature of the packing of coarse clastic material - a fairly uniform size of the clasts. In addition, in most cases, from the surface, the debris is either covered with moss or lichen, or simply has a black “tan crust”. This indicates that the surface layer of debris is not prone to movement in the form of rolling. Hence, apparently, their name is “kurums”, which from the ancient Turkic means either “sheep herd”, or a cluster of stones similar in appearance to a flock of sheep. There are many synonyms for this term in the literature: stone stream, stone river, stone sea, etc.

The most important feature of the kurums is that their coarse clastic cover experiences slow movements down the slope. Signs indicating the mobility of the kurums are: the swell-like nature of the frontal part with the steepness of the ledge close to or equal to the angle of repose of the coarse clastic material; the presence of swells oriented both along the dip and along the strike of the slope; the sintering nature of the kurum body as a whole.

The activity of kurums is evidenced by:

– discontinuity of lichen and moss covers;

– a large number of blocks oriented vertically and the presence of linear zones with long axes oriented along the slope dip;

– large openness of the section, the presence of buried sod and remains of trees in the section;

– deformity of trees located in the zone of contact with kurums;

- plumes of fine earth at the base of the slopes, carried out from the kurum cover by subsurface runoff, etc.

In Russia, Kurums occupy very large areas in the Urals, in Eastern Siberia, in Transbaikalia, on Far East. Kurum formation is determined by climate, lithological features of rocks and the nature of the weathering crust, dissection of the relief and tectonic features of the territory.

The formation of kurums occurs in severe climatic conditions, the main of which is the amplitude of fluctuations in air temperatures, which contributes to the weathering of rocks. The second condition is the presence on the slopes of rocks that are resistant to disintegration, but
fissured, giving large pieces during weathering (lumps, crushed stone). The third condition is abundance precipitation, which form a powerful surface runoff that washes the coarse clastic cover.

The most active kurum formation occurs in the presence of permafrost. Their appearance is sometimes noted in conditions of deep seasonal freezing. The thickness of kurums depends on the depth of the seasonally thawed layer. On the Wrangel Islands, Novaya Zemlya, Severnaya Zemlya, and in some other regions of the Arctic, kurums have a "film" character of a coarse clastic cover (30–40 cm). In the North-East of Russia and the north of the Central Siberian Plateau, their thickness increases to 1 m or more, tending to increase to the south to 2–2.5 m in South Yakutia and Transbaikalia. In the same geological structures, the age of kurums depends on their latitudinal position. So, in the North Polar Urals modern kurum formation takes place, and on Southern Urals most of the kurums are classified as "dead", relic.

In continental regions, the most favorable conditions for kurum formation are found in areas with high humidity. In a temperate climate, intense kurum formation occurs within the bald belt of mountains and the belt of forests. Each climatic zone has its own altitude ranges in which kurum formation is observed. In the Arctic zone, kurums are developed in the altitude range from 50–160 m on Franz Josef Land, to 400–450 m on Novaya Zemlya, and up to 700–1500 m in the north of the Central Siberian Plateau. In the Subarctic, the altitude range is 1000–1200 m in the Polar and Northern Urals, in the Khibiny. In the continental region of the temperate zone, kurums are found at an altitude of 400–500 m in the southern part of the Central Siberian Plateau, 1100–1200 m in the west and 1200–1300 m in the east of the Aldan Highlands, 1800–2000 m in southwestern Transbaikalia. In the continental sector of the subboreal zone, kurums are found at altitudes of 600–2000 m in Kuznetsk Alatau and 1600–3500 m in Tuva. As a result of studying the kurums of Northern Transbaikalia, it was found that only in this region there are about 20 of their morphogenetic varieties (Table 2.49). The kurums differ from each other in terms of the shape in plan, the structure of the kurum body in the section, and the structure of the coarse clastic cover, which is associated with various conditions the formation of kurums.

According to the sources of education, two large classes of kurums are distinguished. The first class includes tumuli, into which coarse clastic material enters from their bed due to its destruction by weathering, removal of fine earth, buckling of debris, and other processes. These are kurums with the so-called internal nutrition. The second class includes kurums, the clastic material of which comes from outside due to the action of gravitational processes (landslides, scree, etc.). Kurums of the second type are spatially localized in the lower parts or at the foot of actively developing slopes and are small in size.

Kurums with internal feeding are divided into two subgroups: those developing on loose deposits and on rocks. Kurums on slopes composed of loose deposits are formed as a result of cryogenic buckling of coarse clastic material and suffusion removal of fine earth from it. They are confined to moraines, deluvial-solifluction accumulations, sediments of ancient alluvial fans and other genetic varieties consisting of blocks, crushed stone with fine-grained aggregate. Often such kurums are laid along shallow erosional hollows and other superimposed exogenous forms.

The most widespread, especially in the goltsovy belt of mountains, are kurums with internal nutrition, developing on rocks of various origins and compositions, resistant to weathering and giving large pieces (blocks, crushed stone) when destroyed. The structure of all types of kurums is significantly influenced by the geological and geomorphological conditions in which they are formed (Table 2.50). On a relatively homogeneous in composition and structure of the primary substrate and slopes with the same slope, the kurum-forming processes manifest themselves relatively evenly over the area. In this case, a single-type section appears along its strike on the kurum slope. The structure and cryogenic features of the kurum cover change mainly down the slope. If the root substrate is heterogeneous in composition and structure, then the formation of the cover occurs unevenly over its entire area as a result of the selective manifestation of exogenous processes. In this case, kurums are formed various shapes(linear, mesh, isometric), belonging to the group of selective weathering of rocks.

The most important feature of kurums, which predetermines their danger, is their structure in the section. It is the structure that determines their geodynamic and engineering-geological features, i.e., the danger of kurums when interacting with various engineering objects. The structure of kurums in sections is diverse. If we take into account the size of the fragments, the nature of their processing and sorting in a vertical section, the presence of bald ice or fine earth, its relationship with the part of the section that is in a permafrost state, and other dangers, then there are no similarly built kurums. However, when summarizing the details of the structure, 13 main types of sections were identified, which correspond to certain conditions of kurum formation and reflect the specifics of the processes occurring in one or another part of the coarse clastic material.

First group unites sections, in the structure of which there is a layer with bald ice. The part of the kurum body, which has such a structure, is named just that - a subfacies with bald ice. This subfacies is an indicator that the kurum is in the mature stage of its development, since the formation of the ice-ground layer occurs due to a decrease in the depth of seasonal thawing as a result of the destruction of rocks and an increase in their moisture content (ice content). The movement of the coarse clastic material of the subfacies is carried out due to thermogenic and cryogenic desertification, plastic deformations of the ice-ground base, as well as the sliding of fragments along it.

These climatic phenomena contribute significantly to pollution 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 impair transparency. 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, in the area Aral Sea an 80-hour storm was recorded.

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 this mist is transferred to southern part Russia and all of Europe from Africa (its northern regions) and the Middle East. And western flows often carry such dust from China (center and north) to the Pacific coast, 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 it occurs in sandy deserts (for example, in the Sahara, Kyzylkum, Karakum, etc.), and, in addition to the smallest particles, the wind carries millions of tons and larger particles (sand) through the air, the term "sandstorm" is already used.

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 Chita, Buryatia, Tuva, Novosibirsk, Orenburg, Samara, Voronezh, Rostov regions, Krasnodar, Stavropol territories, in the 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.

AT Pacific Ocean dust is carried by Chinese storms.

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 hit Karachi and the provinces of Balochistan and Sindh, and the heavy rains that followed resulted in 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 layer and warm air on the outskirts of the southern polar cap of the planet Mars, there are strong winds, 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 the earth's clouds. The atmosphere is heated by the absorption of sunlight by dust.