Dust storms

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

Often occurs during the warm season in desert and semi-desert regions. In addition to the “actual” dust storm, in some cases dust from deserts and semi-deserts can remain in the atmosphere for a long time and reach almost anywhere in the world in the form of a dusty haze.

Dusty haze- an atmospheric phenomenon, a continuous more or less uniform clouding of the atmosphere with a horizontal visibility range of 2 m from 1 to 9 km (sometimes visibility is reduced to several hundred or even several tens of meters) due to dust and soil particles suspended in the air.
It can be observed before or after a dust storm (when the wind weakens), as well as during a distant dust storm, when dust particles raised into the air are carried by the wind over a long distance. At the same time, in the visible surroundings there are no signs of dust rising by the wind from the surface of the earth. Depending on the color of the soil in a given region, distant objects take on a grayish, yellowish or reddish tint.
A dust haze should not be confused with a dust storm.

Dust storms occur less frequently in steppe regions, very rarely in forest-steppe and even forest regions (in the last two zones, a dust storm usually occurs in the summer during severe drought). Dust storms usually occur in temperate zones in early spring, after a winter with little snow and a dry autumn, but sometimes even in winter, in combination with snowstorms.

The main distribution area of dust storms is deserts and semi-deserts of the temperate and tropical climatic zones of both hemispheres of the Earth.
The term dust storm is usually used when a storm occurs over clay and loam soil. When storms occur in sandy deserts(especially in the Sahara, as well as in the Karakum, Kyzylkum, etc.), when in addition to small particles that reduce visibility, the wind also carries millions of tons of larger sand particles over the surface, the term sandstorm is used.
In Russia, dust storms are most often observed in Astrakhan region, in the east Volgograd region and in Kalmykia.
During a squall (before a thunderstorm and torrential rain), short-term (from several minutes to an hour) local dust storms can be observed in the summer even at points located in the forest vegetation zone - including in Moscow and St. Petersburg (1-3 days per summer).
The Sahara Desert and deserts of the Arabian Peninsula are the main sources of dust haze in the Arabian Sea region, with smaller contributions from Iran, Pakistan and India. Dust storms in China carry dust to Pacific Ocean.

Causes

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

A recent study suggests that the initial saltation of sand grains by friction induces an electrostatic field. The bouncing particles acquire a negative charge, which releases even more particles. This process captures twice as many particles as previous theories predict.
Particles are released mainly due to dry soil and increased wind. Gust fronts can occur due to cooling air in the area of a rain storm or dry cold front. After the passage of a dry cold front, convective instability in the troposphere can contribute to the development of a dust storm. In desert regions, dust and sand storms most often occur as a result of thunderstorm downdrafts and the associated increase in wind speed. The vertical dimensions of a storm are determined by the stability of the atmosphere and the weight of the particles. In some cases, dust and sand storms may be confined to a relatively thin layer due to the temperature inversion effect.

Known dust and sand storms

Dust storm in Australia (September 2009)
- According to Herodotus, in 525 BC. e. During a sandstorm in the Sahara, fifty thousand troops of the Persian king Cambyses died.
- In April 1928, in the steppe and forest-steppe regions of Ukraine, the wind lifted more than 15 million tons of chernozem from an area of 1 million km². Black earth dust was transported to the west and settled over an area of 6 million km² in the Carpathian region, Romania and Poland. The height of the dust clouds reached 750 m, the thickness of the black soil layer in the affected regions of Ukraine decreased by 10-15 cm.
- A series of dust storms in the United States and Canada during the Dust Bowl period (1930-1936) forced hundreds of thousands of farmers to relocate.
- On the afternoon of February 8, 1983, a severe dust storm that appeared in the north of the Australian state of Victoria covered the city of Melbourne.
- During periods of multi-year droughts of 1954-56, 1976-78 and 1987-91 in the territory North America Intense dust storms occurred.
- A strong dust storm on February 24, 2007, which appeared in West Texas near the city of Amarillo, covered the entire northern part of the state. Strong winds caused widespread damage to fences, roofs and even some buildings. Also badly damaged international Airport metropolitan area of Dallas-Fort Worth, people came to the hospital with breathing problems.
- In June 2007, a large dust storm occurred in Karachi and the provinces of Sindh and Balochistan, and the subsequent heavy rains led to the death of almost 200 people.
- On May 26, 2008, a sandstorm in Mongolia killed 46 people.
- On September 23, 2009, a dust storm in Sydney caused traffic disruptions and forced hundreds of people to stay home. More than 200 people sought medical help due to breathing problems.
- On July 5, 2011, a huge sandstorm covered the city of Phoenix, the capital of Arizona in the USA. The disaster led to downed power lines, a fire in the city center, and paralyzed air traffic.

In particular, I would like to note the historical event called Dust Bowl.
Dust Bowl, Dust Bowl - a series of catastrophic dust storms that occurred in the prairies of the USA and Canada between 1930 and 1936 (in some regions until 1940). Caused by a combination of anthropogenic (extensive management Agriculture, soil degradation) and natural (drought) factors. The Dust Bowl is one of the most terrible episodes of American history of the 20th century. In the thirties, a severe economic crisis unfolded in the United States. And suddenly another misfortune was added to it: the country was attacked by terrible dust storms, because of which things were very bad.

The term "Dust Bowl" was first used on April 15, 1935 by Associated Press reporter Robert Geiger. It is believed to come from William Gilpin's image of the Great Plains: "fertile bowl, rimmed by mountains." The term refers not only to the time of the dust storms of the 1930s, but also to the region that became their center: the western third of Kansas, southern Colorado, the salient parts of Texas and Oklahoma, and northern New Mexico.
In 1932, 14 dust storms were recorded, in 1933 - 38. The most severe storms took place in May 1934 and April 1935. Huge masses of soil were blown away by winds that met no obstacles in the plowed prairies devoid of natural vegetation, and were transported in the form of black clouds over long distances - up to Atlantic Ocean. April 14, 1935, due to the fact that clouds of dust obscured the sunlight, was called Black Sunday. In the winter of 1934-1935, snow fell in New England, red with dust. Dust pneumonia became widespread among the prairie population, especially in Kansas and Oklahoma.
By 1934, about 40 million hectares of soils had partially or completely lost their upper humus horizon as a result of wind erosion. By 1935, up to 80% of the High Plains was eroded to some degree. By 1938, in Llano Estacado, about 10% of the soils had lost more than 12 cm of the top horizon, another 13.5% had lost from 6 to 12 cm.

For many decades, scientists have tried to understand the cause of this phenomenon. In general, the views of experts converge, but there have always been many unclear details.

Causes of the Dust Bowl

The development of the Great Plains began only in the second half of the 19th century, after the adoption of the Homestead Act and the development of the railway network. The main occupation of the settlers was initially livestock farming, but by 1890, due to overgrazing, a transition to agriculture took place. New wave resettlement and a sharp increase in arable land occurred after the First World War, when grain prices rose.
Agriculture of that time developed extensively. Crop rotations were not used, and no anti-erosion measures were taken. Moreover, farmers typically burned the stubble and left the field empty during the winter (the period of the most intense winds). As a result, soils dried out, their structure was destroyed, dehumification and erosion resistance decreased. The 1930s were relatively dry, which played a significant role in the development of dust storms.

A large number of dust and sand particles. Distributed in deserts, semi-deserts, and 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 prolonged winds that destroy the soil surface. Dust storms, based on 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 rising 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 they arise

Dust storms occur in deserts, semi-deserts and steppe regions, where there is soil uncovered by grass. Dust storms capable of transporting 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 with high speed.

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

3. Actions in dust storm conditions

A person caught in a dust storm needs to lie down on the leeward side of any tall object that holds firmly to the ground - a stone, a thick bush, etc. The respiratory tract should be protected from sand and dust with a cloth bandage. Place a closed container with a supply of water next to you, under your arm.

4. In Ukraine

In February 1951, strong storms occurred in the Azov region with a speed of 16-18 m/s. They removed the weak snow cover and began to blow away the exposed soil. The snow, together with the blown soil, created many obstacles, forming black snowdrifts up to 1-1.5 meters high. The blowing away of soil and winter crops continued into the spring months.

Dust storms are currently occurring temporarily in southern Ukraine. First of all in

Dust storm- a strong wind capable of transporting millions of tons of dust over a distance of several thousand kilometers.

This phenomenon, although meteorological, is associated with the state of the soil cover and the terrain. They akin to blizzards: for both to occur, a strong wind and sufficiently dry material on the surface of the earth is needed that can rise into the air and remain suspended there for a long time. But if for the appearance of blizzards you need dry, non-packed, snow-free snow lying on the surface and a wind speed of 7-10 m/s or more, then for the occurrence of dust storms the soil must be loose, dry, devoid of grass or any significant snow cover and wind speed was at least 15 m/s.

Depending on the structure and color of the soils blown by the wind, there are black storms(on chernozems), characteristic of Bashkiria, Orenburg region; brown or yellow storms(on loams and sandy loams), typical Central Asia; red storms(on red-colored soils stained with iron oxides), characteristic of deserts and semi-deserts of our country, desert areas of Iran and Afghanistan); white storms(on salt marshes), characteristic of some regions of Turkmenistan, the Volga region, and Kalmykia.

A dust storm in its scale and consequences can be equated to a major natural disasters. V.V. Dokuchaev describes one of the cases of a dust storm in Ukraine in 1892: “Not only was the thin snow cover completely torn off and carried away from the fields, but also the loose soil, bare of snow and dry as ash, was thrown up by whirlwinds at 18 degrees below zero. Clouds of dark earthen dust filled the frosty air, covering roads, covering gardens in places the trees were carried to a height of 1.5 meters, lay down in shafts and mounds on the streets of villages and greatly impeded movement along railways: we even had to tear railway stops away from snowdrifts of black dust mixed with snow.”

During a dust storm in April 1928 in the steppe and forest-steppe regions of Ukraine, the wind lifted from the area 1 million km2 more than 15 million tons black soil Black earth dust was transported to the west and settled over an area of 6 million km2 in the Carpathian region, Romania and Poland. The height of dust clouds over Ukraine has reached 750 m. The thickness of the chernozem layer in the steppe regions of Ukraine after this storm decreased by 10-15 cm.

The danger of this phenomenon also lies in the terrible strength of the wind and its extraordinary impetuosity. During dust storms over Central Asia, the air is sometimes saturated with dust up to a height of several kilometers. Aircraft caught in a dust storm are in danger of being destroyed in the air or upon impact with the ground; In addition, the visibility range in a dust storm can be reduced to tens of meters. There have been cases when during the day this phenomenon became as dark as night, and even electric lighting did not help. If we add that on earth, dust storms can lead to the destruction of buildings. windbreaks, not to mention the pervasive dust that fills houses, saturates people’s clothes, clouds their eyes, and makes breathing difficult, then it will become clear. how dangerous is this phenomenon and why is it called a natural disaster...

Dust storms usually last for several hours, but in some cases they last for several days. Some dust storms originate far beyond the borders of our country - in North Africa, on the Arabian Peninsula, from where air currents bring clouds of dust to us.

And here Hurricanes and dust storms are not on their way. Dust and sand storms in the Sahara can put an end to the activity of tropical hurricanes in the Atlantic. One of the places where these dangerous eddies originate is the ocean area adjacent to west coast Black continent. But as the results of a study conducted by a group of scientists from the University of Wisconsin-Madison show, it is precisely here that the eastern winds blowing from the depths of the continent carry clouds of Saharan sand dust.

Experts analyzed satellite images, made in 1982-2005. and compared them with tropical storm activity. As a result, scientists have established an inversely proportional relationship between these phenomena: in those years when strong sand whirlwinds were observed in Africa, tropical storms rarely occurred, and vice versa - when there were almost no storms, storms developed actively.

The anti-hurricane effect mechanism is simple. Firstly, the dusty-sandy substance is heavier than air, and falling down, it creates downward air currents that inhibit the development of a hurricane. Secondly, a powerful air flow blowing from the continent creates wind shear in the middle troposphere, which also contradicts the conditions for the formation of tropical vortices. And thirdly, particles of sand and dust suspended in the air absorb part of the latent thermal energy released during condensation of water vapor. Scientists believe that they are only at the beginning of a long research journey in this area.

Dust storm in Texas in 1935

Dust storm, South Dakota, 1937

Stafeev Daniil Valerievich

Relevance: In the Lower Volga region, Kazakhstan, Kalmykia there has been intense heat for a long time with dry winds and dust storms.

I want to know: What types of storms are there? Why are they dangerous? What harm is done to the environment?

Purpose of the work: Is it possible to prevent storms? How to deal with them?

Download:

Preview:

To use presentation previews, create a Google account and log in to it: https://accounts.google.com

Slide captions:

In the Lower Volga region, Kalmykia, and Kazakhstan, there has been intense heat for a long time with dry winds and dust storms. Dust storms are an atmospheric phenomenon in the form of the transfer of large quantities of dust by wind. What types of storms are there? Why are they dangerous? What harm is done to the environment? Can storms be prevented? How to deal with them? I know: I want to know: Purpose of work: Relevance

What are dust storms? Where they sweep, plants dry out and die, even with a sufficient supply of moisture in the soil Dust (sand) storm - wind with a large amount of dust and sand Dust (sand) drift - transfer of dust (soil particles, grains of sand) by the wind Arabic name “khamsin” ", or "shamal" A dust storm is called "Afghan" "Burning without fire" - this is the name of dry winds. Dunes are majestic hills that move colossal masses of sand across the Earth

Dust storms are Black Brown or yellow Red White chernozems Loams red earth solonchaks are characteristic of the southern and south-eastern regions of Central Asia, deserts and semi-deserts of our country in Central Asia, Turkmenistan, the Volga region, Kalmykia.

Storms are subdivided

How do dust storms occur? cold air invades under a layer of warm air small loose particles rise occur during very strong and prolonged winds carry dust over significant distances (up to hundreds and thousands of km) occurs in the warm season occur in early spring after a winter with little snow after a dry autumn

Where can dust storms be observed? More often than desert and semi-desert regions. More often than forest-steppe regions in steppe regions.

Signs of the appearance of dust storms A black stripe appears, which approaches, increasing in size. It covers the firmament, For a moment there is a temporary lull. Everything around is enveloped in suffocating dust. Sand and dust, rushing at high speed, penetrate everywhere.

Why are dust storms considered major natural disasters? It became as dark as at night Dangerous due to the strong wind force and extraordinary gusty Causes suffocation After such a storm, often where the seedlings were green, a desert spreads Covered with dust large areas fields and pastures

Methods of control: creation of shelterbelts, snow retention and water retention Grass sowing, plowing

Damage from dust storms Winter crops are covered with soil and sand Seeds of spring crops are blown out. Grain yields are decreasing. Lack of moisture in upper layers soil. The fertile layer of soil is depleted. The air is thick with dust. Destruction of buildings. Windbreaks. Airplanes are in danger of being destroyed in the air or when they hit the ground.

Hot dry winds blow from Kazakhstan. They dry out the air and raise dust storms. Particles of parched earth easily fall prey to strong winds. You can fight the elements by planting shelterbelts and herbs. My opinion.

Helped during the work: http://vajtgeograf.narod.ru/stihiinie_bedstviya_pogoda_i_klimat/smerchi_i_pilnie_buri http://www.agps-mipb.ru/index.php/2011-01-08-07-37-51/407-pylnye- buri.html http://www.musvid.net/videocat/ Kalmykia /4 http://foto.awd.ru/details.php?image_id=67288 http://pokrovk.ucoz.ru/photo/12-0 -186-3 http://www.photosight.ru/photos/2648926/ http://www.chaspik.spb.ru/tag/stihiya/ http://geolog8.ya.ru/posts.xml?tb= 80 http://fotki.yandex.ru/users/xx42na/view/144382/ http://sshvrt.com/POSHVY.htm http://fotki.yandex.ru/users/dashulia-13/view/396950/ http://shoot.3dn.ru/photo http://artpano.ru/42/43.html http://ru-capital.ru/mes1733.html http://www.0vosh.ru/technika.php

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

Often occurs in the warm season in regions. When a certain threshold of wind speed is exceeded (depending on the mechanical composition of the soil and its moisture), particles break off from the surface and are transported by 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 a 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 climate zones of 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 . Environmentalists believe that irresponsible management of the Earth's dry regions, such as ignoring the system, lead to and climate change at 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 over the surface. Term dust storm refers more to the phenomenon of transport of small particles over distances of up to several thousand km, especially when storms “cover” urban areas.

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 region; on - in , , , , areas, in ; in the 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 the summer even at points located in the forest vegetation zone - incl. V and (1-3 days during the summer).

Causes

A recent study suggests that the initial grains of sand through friction induces . The bouncing particles acquire a negative charge, which releases even more particles. This process captures twice as many particles as previous theories predict.Particles are released mainly due to and wind. Gust fronts may occur as air cools after a strong with rain or may be dry . After the passage of a dry cold front instability could create a dust storm. In desert areas, dust and sand storms most often occur as a result of thunderstorm outlets and increased wind speeds. The vertical dimensions of a storm are determined by the stability of the atmosphere and the weight of the particles. In some cases, dust and sand storms may be confined to a relatively thin layer due to the temperature inversion effect. 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 shelterbelts, 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 carry enormous volumes of dust, so that the storm front can appear as 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 basin and in the area of convergence of boundaries, And . Over the past half century (since the 1950s), Saharan dust storms have increased approximately 10-fold, causing a decrease in the thickness of the topsoil in, Chad, northern and . In the 1960s, there were only two dust storms in Mauritania, but currently there are 80 storms a year. Volume of dust blown from the Sahara towards the Atlantic Ocean in June five times more than a year ago, which could cool the Atlantic and reduce activity slightly .

Economic consequences

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: decreased , affecting air and road transport; reducing the amount of sunlight reaching the Earth's surface; thermal blanket effect; adverse effects on the respiratory system of living organisms.

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

Extraterrestrial dust storms

The strong difference in temperature between the ice shell and warm air at the edge of Mars's southern polar cap leads to the occurrence 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 thereby heats the atmosphere.