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. More details about them will be discussed in the following article.
Definition
A dust storm, or sandstorm, is the 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.
Causes of dust storms
It's all about the terrible heat, due to which the soil dries out a lot and thenthe surface layer breaks up into microparticles, picked up by a strong wind.
But dust storms begin at certain critical wind speeds, depending on the terrain and soil structure. For the most part, they begin at wind speeds in the range of 10-12 m/s. And on loess soils, 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 measured 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 raised dust from the surface of the earth remains in the air in suspension 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 for long distances from the source is called advective haze.
Tropical air masses carry this mist to the southern part of Russia and all of Europe from Africa (its northern regions) and the Middle East. And western currents 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 the structure of the soil and 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 (peculiar toUSA and Central Asia - loam and sandy loam);
- red (red-colored soils stained with iron oxides of the desert areas of Afghanistan and Iran;
- white (s alt marshes of some regions of Kalmykia, Turkmenistan and the Volga region).
Geography of storms
The emergence 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 clay 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 (south of Kazakhstan), in the western part of Kazakhstan, on the Caspian coast, in Karakalpakstan and in Turkmenistan.
Where are dust storms in Russia? 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 aredeserts of the Arabian Peninsula 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 appear as a dense and high wall of dust (up to 1.6 km.). The storms coming from the Sahara desert are known as Samum, Khamsin (Egypt and Israel) and Haboob (Sudan).
For the most part in the Sahara, storms occur in the Bodele Basin 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 dust storms in the Sahara has increased by about 10 times, which caused a significant decrease in the thickness of the surface layer of soil in Chad, Niger, 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.
Scientists-ecologists believe that 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 climate state of planet Earth at the global level.
Ways to fight
Dust storms, like many other natural phenomena, bring great harm. In order to reduce and even prevent their negative consequences, it is necessary to analyze the features of the areas - relief, microclimate,the direction of the winds prevailing here, and to carry out appropriate activities that will help reduce the wind speed near the earth's surface and increase the adhesion of soil particles.
In order to reduce the wind speed, certain activities are carried out. Systems of wind-shelter wings and forest belts are being created everywhere. Non-moldboard plowing, abandoned stubble, crops of perennial grasses, strips of perennial grasses interspersed with crops of annual crops have a significant effect on increasing the adhesion of soil particles.
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 B. C. 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, a severe storm in northern 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 caused 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 were hard hit. There werehuman casu alties.
A final word about extraterrestrial dust storms
Martian dust storms happen like this. Due to the strong temperature difference 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 the earth's clouds. The atmosphere is heated by dust absorbing sunlight.
