I am always surprised when hail comes. How is it that on a hot summer day during a thunderstorm, peas of ice fall to the ground? In this story I will tell you why the hail is coming.

It turns out that hail forms when raindrops cool down, passing through the cold layers of the atmosphere .. Single drops turn into tiny hailstones, but then amazing transformations take place with them! Falling down, such a hailstone collides with the oncoming air flow from the ground. Then it rises up again. Unfrozen raindrops stick to it and it sinks again. The hailstone can make a lot of such movements from bottom to top and back and its size will increase. But there comes a moment when it becomes so heavy that the ascending air currents are no longer able to support it in weight. Then the moment comes when the hailstone rushes rapidly to the ground.

A large hailstone, cut in half, is like an onion: it consists of several layers of ice. Sometimes hailstones resemble a layer cake, where ice and snow alternate. And there is an explanation for this - using such layers, you can calculate how many times a piece of ice made a wandering from rain clouds into the supercooled layers of the atmosphere.

Moreover, hailstones can take the form of a ball, cone, ellipse, look like an apple. Their speed towards the ground can reach 160 kilometers per hour, so they are compared to a small projectile. Indeed, hail can destroy crops and vineyards, break glass and even break through the metal skin of a car! The damage caused by hail on the entire planet is estimated at a billion dollars a year!

But everything, of course, depends on the size of the hailstones. So in 1961 in India a hailstone weighing 3 kilograms on the spot killed ... an elephant! In 1981, Guangdong Province, China, during a thunderstorm, hailstones weighing seven kilograms fell. Five people were killed and about ten thousand buildings destroyed. But most of all people - 92 people - died due to kilogram hailstones in 1882 in Bangladesh.

People today learn to fight hail... A special substance (called a reagent) is injected into the cloud with the help of rockets or projectiles. As a result, hailstones are smaller and have time to completely or largely melt in warm air layers even before falling to the ground.

It is interesting:

Even in ancient times, people noticed that loud noise prevents the formation of hail or causes the appearance of smaller hailstones. Therefore, to save the crops, bells were rang or cannons were fired.

If hail catches you indoors, then stay as far away from windows as possible and do not leave the house.

If the hail found you on the street, then try to find shelter. If you run far to it, be sure to protect your head from the blows of hailstones.

The hail is a very serious natural disaster, causing colossal damage to agriculture every year. Hail is actually chunks of ice falling from the sky. It is not uncommon for the size of ice floes to reach the size of an egg or even an apple.

Grain harvest, vineyards, orchards can be in 15 minutes. die due to "bombing" from the air large hail... According to the Vysokogorny Geophysical Institute, only one hail attack on August 19, 2015 damaged the economy of the North Caucasus about 6 billion rubles.

In the Middle Ages, to prevent the formation of large hailstones, people rang bells and fired cannons, trying to force an ominous cloud to spill onto the Earth with sound waves, before the hailstones in it reached large sizes. Now they use modern and more reliable methods of penetration into a thundercloud - they launch anti-hail pyrotechnic shells and rockets.

So what is hail, how is it formed, and what does the size of hailstones depend on? In summer, the air above the Earth's surface warms up strongly, an ascending stream is formed, which can be so strong that it can bring steam to an altitude of 2.5 km, where the temperature is much below zero, as a result of which the water droplets are supercooled, and if they rise even higher (by height of 5 km), ice hailstones begin to form. In the future, hailstones can grow to significant sizes due to freezing of supercooled drops colliding with them, as well as freezing of hailstones among themselves.

It is important to note that large hailstones can appear only if there are strong ascending currents in the clouds that can keep them from falling to the ground for a long time. When the speed of the upward flow in the cloud is less than 40 km / h, for a long time hailstones will not be held in the cloud - and they fall down rather quickly, without having time to grow, and if they fall from a relatively low height, they can melt, as a result of which showers fall on the ground. The thicker the cloud, the more likely it is that the hailstones will grow to a large size and large pieces of ice will fall on the Earth.

The clouds from which the hail falls are characterized by a dark gray, ash color and white, as if tattered, tops. Each cloud consists of several clouds piled up on top of each other: the lower one is usually at a low altitude above the ground, while the upper one is at a height of 5, 6 and even more than thousand meters above the earth's surface. Sometimes the lower cloud stretches out in the form of a funnel, as is characteristic of the phenomenon of tornadoes. Hail is usually accompanied by a thunderstorm and occurs in thunderstorm vortices (tornadoes, tornadoes) with a strong upward current of air. Phenomena such as tornado, tornado and hail are closely related to each other and to cyclonic activity. Hail vortices are sometimes unusually strong.

Most often, hail falls in temperate latitudes. Moreover, over water spaces, it is much less common (above the earth's surface, ascending air currents are more frequent than over the sea).

Hail in mountainous areas is the largest and most dangerous. This can be explained by the fact that in hot weather the relief of the earth's surface in the mountains warms up unevenly, there are very powerful ascending currents that raise water vapor particles to a height of up to 10 km, where the air temperature is below -40 ° C. A large hail flying from this height can reach a speed of 160 km / h and lead to the loss of crops, serious damage to buildings, vehicles, and the death of people and animals.

There are many catastrophic cases of large hail. So, on April 14, 1986 in Bangladesh, in the city of Gopalgandezh, kilogram hailstones fell from the sky. The hail killed 92 people. Even heavier chunks of ice bombed Indian Huderabad in 1939. They weighed at least 3.4 kilograms. Judging by the destruction, the largest hailstorm took place in China in 1902.

And now some facts about hail and measures to combat it in our country.

In Russia, the North Caucasus and the south are most susceptible to natural disasters, in particular, the fallout of a strong hail. On average in the North Caucasus for the entire summer season hail damages areas of about 300-400 thousand hectares, of which the harvest is completely destroyed on an area of ​​142 thousand hectares.

In recent decades, due to global warming climate the frequency and intensity of natural phenomena in Russia is increasing by 6-7% per year, respectively, and losses from natural disasters are also growing. More than 500 people are registered in the country annually. emergencies, including hail and drought, tornadoes have become more frequent.

In 2016, a hailstorm dealt its first tangible blow to North Caucasus in May-June. According to the Ministry of Emergency Situations, as a result of the disaster in the Stavropol Territory, more than 900 private households were damaged, 70.1 thousand hectares of crops were damaged by hail, of which 17.8 thousand hectares were destroyed. V North Ossetia degree with egg held on June 5, destroyed 369.8 hectares of crops of potatoes, corn for grain, barley, the amount of damage is estimated at 27 million rubles.

One of the methods of protection against large hail is to install protective nets over vegetable plantations, vine plantations, but the nets do not always withstand the pounding of very large and rapid hail.

More than fifty years ago, 10 paramilitary services were created in the USSR to combat hail, including three in the North Caucasus - Krasnodar, North Caucasian and later Stavropol service, which protect an area of ​​2.65 million hectares in the North Caucasus and South federal districts. According to experts, the territory of protection must be expanded. The creation of new points of influence, command posts will require 497 million rubles. and for their maintenance annually - about 150 million rubles. However, according to the calculations of scientists, protection from hail will give economic effect about 1.7 billion rubles.

Anti-hail rockets spray reagent in areas of new growth of hail and hail-hazardous clouds, which leads to accelerated precipitation and rainfall instead of hail. At the end of the 1950s, the first anti-hail projectile "Elbrus-2", fired from an anti-aircraft gun KS-19, was tested. Since then, the shells and installations have been improved. The most recent development in 2014 is the As-Eliya small anti-hail complex consisting of the As rocket and the Eliya-2 36-barreled automated rocket launcher with wireless remote control.

Summer weather is changeable. Black clouds suddenly appear in the sky, which are the harbingers of rain. But contrary to our expectations, instead of rains, pieces of ice begin to fall on the ground. And this despite the fact that the street is quite hot and stuffy. Where do they come from?

Firstly, this natural phenomenon is usually called hail. It is quite rare and occurs only under certain conditions. As a rule, hail falls once or twice during the summer. The grains themselves are pieces of ice, ranging in size from a few millimeters to several centimeters. Larger grains are extremely rare and are most likely an exception to the general rule. As a rule, they are not larger than a pigeon's egg. But even such a hail is very dangerous, as it can damage grain crops and cause significant harm to vegetable growers' plantations.

As for the shape of the hailstones, they can be completely different: a ball, a cone, an ellipse, a crystal. They may contain pieces of dust, sand or ash inside. In this case, their size and weight can increase significantly, sometimes up to one kilogram.

In order for hail to occur, two conditions are necessary - low temperature upper atmosphere, and powerful updrafts. What happens in this case? Water droplets in the cloud freeze and turn into pieces of ice. Under the influence of gravity, they would have to descend into the lower, warmer layers of the atmosphere, melt, and rain down on the earth. But due to strong ascending air currents, this does not happen. The ice floes are picked up, move chaotically, collide, and freeze with each other. There are more and more of them every hour. As their size increases, so does their mass. In the end, there comes a moment when their gravity begins to exceed the strength of the ascending air currents, which leads to the emergence of hail. Sometimes hail is mixed with rain, and is also accompanied by thunder and lightning.

If you look at the structure of the hailstone, it looks incredibly like an onion. The only difference is that it consists of numerous layers of ice. In fact, this is the same Napoleon cake, only instead of cream and cakes, it contains layers of snow and ice. By the number of such layers, it is possible to determine how many times a hailstone was picked up by the air flow and returned to the upper atmosphere.

Why is hail dangerous?

The hailstones fall to the ground at a speed of 160 km / h. If such a piece of ice hits a person on the head, then he can get serious injury. Hail can damage your car, shatter window glass, and damage plants.

Hail can be successfully dealt with. To do this, a projectile is fired into the cloud, which contains an aerosol that has the ability to reduce the size of ice floes. As a result, ordinary rain falls on the ground instead of hail.

Hail is one of the most unpleasant natural phenomena. Of course, according to destructive force it cannot be compared to a tsunami or an earthquake, but hail can cause enormous damage.

Every year, hailstorms kill crops, damage buildings, cars, property, and even kill animals.

People have always tried to explain the nature of hail, predict its fall, and reduce the damage caused. Despite the fact that modern meteorology has explained how hail appears and has learned to predict with great accuracy how it will fall in a particular region, hail still annoys a person.

Grad: what is it?

Hail is a type of rainfall that occurs in rain clouds. The pieces of ice can form as round balls or have jagged edges. Most often these are peas white, dense and opaque. The hail clouds themselves are characterized by a dark gray or ash tint with ragged white ends. The percentage probability of solid precipitation depends on the size of the cloud. With a thickness of 12 km, it is approximately 50%, but upon reaching 18 km, hail will be mandatory.

The size of the ice floes is unpredictable - some may look like a small snowball, while others reach several centimeters in width. The largest hail was seen in Kansas, when "peas" up to 14 cm in diameter and weighing up to 1 kg fell from the sky!

They can be accompanied by precipitation in the form of rain, in rare cases - snow. Also, loud thunder and lightning flashes occur. In susceptible regions, severe hail can occur together with a tornado or tornado.

When and how hail occurs

Most often, hail forms in hot weather during the daytime, but in theory it can appear as low as -25 degrees. It can be seen during rain or just before other precipitation falls. After a rainstorm or snowfall, hail is extremely rare, and such cases are the exception rather than the rule. The duration of such precipitation is short - usually everything ends in 5-15 minutes, after which you can observe good weather and even bright sun. Nevertheless, the layer of ice that fell out in this short period of time can reach several centimeters in thickness.

Cumulus clouds, in which hail is formed, consist of several separate clouds located on different heights... So the top ones are more than five kilometers above the ground, while the others "hang" quite low, and they can be seen with the naked eye. Sometimes these clouds resemble funnels.

The danger of hail lies in the fact that not only water gets into the ice, but also small particles of sand, debris, salt, various bacteria and microorganisms, which are light enough to rise into the cloud. They are held together with the help of frozen steam and turn into large balls that can reach record sizes. Such hailstones sometimes rise several times into the atmosphere and again fall into the cloud, collecting more and more “components”.

To understand how hail forms, it is enough to look at one of the fallen hailstones in a section. In structure, it resembles an onion, in which transparent ice alternates with translucent layers. Secondly, there is a variety of "garbage". Out of curiosity, you can count the number of such rings - that is how many times the piece of ice rose and fell, migrating between the upper layers of the atmosphere and the rain cloud.

The reasons for the appearance of hail

In hot weather, hot air rises, carrying along with it particles of moisture, which evaporate from reservoirs. During the ascent, they gradually cool down, and upon reaching a certain height, they turn into condensation. From it, clouds are obtained, which will soon pour rain or even a real downpour. So if there is such a simple and understandable water cycle in nature, then why is there hail?

Hail happens because on hot days, hot air flows to record heights, where temperatures drop well below freezing. The supercooled droplets that have crossed the 5 km threshold turn into ice, which then fall out in the form of precipitation. Moreover, even for the formation of a small pea, more than a million microscopic particles of moisture are needed, and the speed of air flows must exceed 10 m / s. It is they who keep the hailstone inside the cloud for a long time.

As soon as the air masses are not able to withstand the weight of the formed piece of ice, the hailstones are torn down from a height. However, not all of them will reach the ground. Small pieces of ice will have time to melt on the way, and will fall out in the form of rain. Since quite a few factors are required to coincide, the natural phenomenon of hail is quite rare and only in certain regions.

Output data of the collection:

About the mechanism of hail formation

Ismailov Sohrab Akhmedovich

Dr. chem. Sci., senior Researcher, Institute of Petrochemical Processes of the Academy of Sciences of the Republic of Azerbaijan,

Republic of Azerbaijan, Baku

ABOUT THE MECHANISM OF THE HAIL FORMATION

Ismailov Sokhrab

doctor of chemical Sciences, Senior Researcher, Institute of Petrochemical Processes, Academy of Sciences of Azerbaijan, the Republic of Azerbaijan, Baku

ANNOTATION

A new hypothesis has been put forward about the mechanism of hail formation under atmospheric conditions. It is assumed that, in contrast to the known previous theories, the formation of hail in the atmosphere is due to the generation of high temperature during a lightning strike. The sharp evaporation of water along the discharge channel and around it leads to its sharp freezing with the appearance of hail of different sizes. For the formation of hail, the transition of the zero isotherm is not necessary; it is also formed in the lower warm layer of the troposphere. The storm is accompanied by hail. Hail occurs only during severe thunderstorms.

ABSTRACT

Put forward a new hypothesis about the mechanism of formation of hail in the atmosphere. Assuming it "s in contrast to the known previous theories, hail formation in the atmosphere due to the generation of heat lightning. Abrupt volatilization water discharge channel and around its freezing leads to a sharp appearance with its hail different sizes. For education is not mandatory hail the transition of the zero isotherm, it is formed in the lower troposphere warm.Storm accompanied by hail.Hail is observed only when severe thunderstorms.

Keywords: hailstone; zero temperature; evaporation; cold snap; lightning; thunderstorm.

Keywords: hailstone; zero temperature; evaporation; cold; lightning; storm.

A person often encounters terrible natural phenomena and fights tirelessly against them. Natural disasters and consequences of catastrophic natural phenomena (earthquakes, landslides, lightning, tsunamis, floods, volcanic eruptions, tornadoes, hurricanes, hail) attract the attention of scientists all over the world. It is no coincidence that a special commission for accounting of natural disasters - UNDRO has been created at UNESCO (United Nations Disaster Relief Organization). Having cognized the necessity of the objective world and acting in accordance with it, man subjugates the forces of nature, makes them serve his purposes and turns from a slave of nature into the ruler of nature and ceases to be powerless before nature, becomes free. One of these terrible disasters is hail.

At the site of the fall, hail, first of all, destroys cultivated agricultural plants, kills livestock, as well as the person himself. The fact is that a sudden hail attack with a large influx precludes protection from it. Sometimes, in a matter of a minute, the surface of the earth is covered with hail 5-7 cm thick.In the Kislovodsk region, hail fell in 1965, covering the ground with a layer of 75 cm. Usually, hail covers 10-100 km distance. Let's remember a few terrible events from the past.

In 1593, in one of the provinces of France, due to a raging wind and flashing lightning, hail fell with an enormous weight of 18-20 pounds! As a result, much damage was caused to crops and many churches, castles, houses and other structures were destroyed. People themselves became victims of this terrible event. (It should be borne in mind that in those days the pound as a unit of weight had several meanings). It was a terrible natural disaster, one of the most catastrophic hail attacks ever to hit France. In eastern Colorado, USA, about six hail attacks occur each year, each causing huge losses... Hailings most often occur in the North Caucasus, Azerbaijan, Georgia, Armenia, in mountainous regions Central Asia... From June 9 to June 10, 1939 in the city of Nalchik, hail fell the size of a hen's egg, accompanied by a heavy downpour. As a result, over 60 thousand hectares were destroyed. wheat and about 4 thousand hectares of other crops; about 2 thousand sheep were killed.

When it comes to a hailstone, first of all, they note its size. Hailstones usually vary in size. Meteorologists and other researchers pay attention to the largest ones. It is curious to know about absolutely fantastic hailstones. Ice blocks weighing 2-3 fell from heaven in India and China kg. They even say that in 1961 in North India a heavy hailstone killed an elephant. April 14, 1984 at small town Gopalganj of the Republic of Bangladesh, hailstones weighing 1 kg fell , leading to the death of 92 people and several dozen elephants. This city is even listed in the Guinness Book of Records. In 1988, 250 people were victims of hail in Bangladesh. And in 1939, a hailstone with a weight of 3.5 kg. More recently (05/20/2014) in the city of São Paulo, Brazil, hailstones of such a large dimension fell out that heaps of them were removed from the streets with heavy equipment.

All these data indicate that damage caused by hail to human life has at least essential compared to other extraordinary natural phenomena... Judging by this, a comprehensive study and finding the cause of its formation with the involvement of modern physicochemical research methods, as well as the fight against this nightmare phenomenon are urgent tasks for humanity around the world.

What is the current hail formation mechanism?

I will note in advance that there is still no correct and positive answer to this question.

Despite the creation of the first hypothesis on this matter in the first half of the 17th century by Descartes, however scientific theory hail processes and methods of influencing them were developed by physicists and meteorologists only in the middle of the last century. It should be noted that even in the Middle Ages and in the first half of the 19th century, several assumptions were put forward by various researchers, such as Bussengo, Shvedov, Klossovsky, Volta, Reye, Ferrell, Hahn, Faraday, Soncke, Reynold, etc. Unfortunately, their theories have not received confirmation. It should be noted that the latest views on this issue are not scientifically substantiated, and there are still no comprehensive ideas about the mechanism of hail formation. The presence of numerous experimental data and a body of literature on this topic made it possible to suggest the following mechanism of hail formation, which was recognized by the World Meteorological Organization and continues to operate to this day (so that there are no disagreements, we literally give out these arguments).

"Rising from earth surface on a hot summer day, warm air cools with height, and the moisture contained in it condenses, forming a cloud. Supercooled droplets in clouds are found even at temperatures of -40 ° C (altitude about 8-10 km). But these drops are very unstable. The smallest particles of sand, salt, combustion products and even bacteria raised from the earth's surface, when colliding with supercooled droplets, upset the delicate balance. Supercooled droplets that come into contact with solid particles turn into an icy hailstone embryo.

Small hailstones exist in the upper half of almost every cumulonimbus cloud, but most often such hailstones melt as they approach the earth's surface. So, if the speed of ascending currents in a cumulonimbus cloud reaches 40 km / h, then they are unable to hold the incipient hailstones, therefore, passing through the warm layer of air at an altitude of 2.4 to 3.6 km, they fall out of the cloud into in the form of small "soft" hail, or even in the form of rain. Otherwise, ascending air currents raise small hailstones to air layers with temperatures ranging from -10 ° C to -40 ° C (altitude between 3 and 9 km), the diameter of the hailstones begins to grow, sometimes reaching several centimeters. It is worth noting that in exceptional cases, the speed of ascending and descending streams in the cloud can reach 300 km / h! And the higher the rate of updrafts in a cumulonimbus cloud, the greater the hail.

It will take over 10 billion supercooled water droplets to form golf-ball-sized hailstones, and the hailstones must remain in the cloud for at least 5-10 minutes to reach such a large size. It should be noted that the formation of one drop of rain requires about a million of these small supercooled drops. Hailstones with a diameter of more than 5 cm are found in supercellular cumulonimbus clouds with very powerful updrafts. It is supercell thunderstorms that generate tornado tornadoes, heavy showers and intense squalls.

Hail usually falls during severe thunderstorms in the warm season, when the temperature at the Earth's surface is not lower than 20 ° C. "

It should be emphasized that even in the middle of the last century, or rather, in 1962, F. Ludlem also proposed a similar theory, which provides for the condition for the formation of hailstones. He also examines the process of formation of hailstones in the supercooled part of the cloud from small water droplets and ice crystals by coagulation. Last operation should occur with a strong rise and fall of the hailstone of several kilometers, crossing the zero isotherm. According to the types and sizes of hailstones, modern scientists also say that hailstones during their "life" are repeatedly carried up and down by strong convection currents. As a result of a collision with supercooled drops, hailstones increase in size.

The World Meteorological Organization in 1956 gave a definition of what hail is : “Hail - precipitation in the form of spherical particles or pieces of ice (hailstones) with a diameter of 5 to 50 mm, sometimes more, falling out in isolation or in the form of irregular complexes. The hailstones consist only of transparent ice or a number of its layers at least 1 mm thick, alternating with translucent layers. Hail is usually observed during severe thunderstorms " .

In almost all former and contemporary sources on this issue indicate that hail forms in a powerful cumulus cloud with strong updrafts. It's right. Unfortunately, we have completely forgotten about lightning and thunderstorms. And the subsequent interpretation of the formation of the hailstone, in our opinion, is illogical and difficult to imagine.

Professor Klossovsky carefully studied external views hail and discovered that they, in addition to the spherical shape, have a number of other geometric forms of existence. These data indicate the formation of hailstones in the troposphere by a different mechanism.

After reading all of these theoretical views, several intriguing questions caught our attention:

1. The composition of the cloud located in the upper part of the troposphere, where the temperature reaches approximately -40 o C, already contains a mixture of supercooled water droplets, ice crystals and sand particles, salts, bacteria. Why is the fragile energy balance not disturbed?

2. According to the recognized modern general theory, the hailstones could arise without a lightning or thunderstorm. To form hailstones with large size, small pieces of ice, must necessarily go up several kilometers (at least 3-5 km) and go down, crossing the zero isotherm. Moreover, this should be repeated until enough large size hailstone. In addition, the higher the velocity of the ascending currents in the cloud, the larger the hailstone should be (from 1 kg to several kg) and for enlargement it should remain in the air for 5-10 minutes. Interesting!

3. In general, it is difficult to imagine that such huge ice blocks with a weight of 2-3 kg will be concentrated in the upper layers of the atmosphere? It turns out that the hailstones were even larger in a cumulonimbus cloud than those observed on earth, since part of it will melt when falling, passing through the warm layer of the troposphere.

4. Since meteorologists often confirm: “... hail usually falls during strong thunderstorms in the warm season, when the temperature at the Earth's surface is not lower than 20 ° C ", however, do not indicate the cause of this phenomenon. Naturally, the question arises, what is the effect of a thunderstorm?

Hail almost always falls before or simultaneously with a shower, and never after. It drops out mostly in the summer and during the day. Hail at night is a rare occurrence. Average duration hail - from 5 to 20 minutes. Hail usually occurs where a strong lightning strike occurs and is always associated with a thunderstorm. There is no hail without a thunderstorm! Therefore, the reason for the formation of hail, it is necessary to look for it in this. The main disadvantage of all existing mechanisms of hail formation, in our opinion, is the lack of recognition of the dominant role of a lightning discharge.

Studies of the distribution of hail and thunderstorms in Russia, carried out by A.V. Klossovsky, confirm the existence of the closest connection between these two phenomena: hail, together with thunderstorms, usually occurs in the southeastern part of cyclones; it is more common where thunderstorms are more common. The North of Russia is poor in cases of hail, in other words, hailstorms, the cause of which is explained by the absence of a strong lightning discharge. What role does lightning play? There is no explanation.

Several attempts to find a connection between hail and thunderstorms were made in the middle of the 18th century. Chemist Guyton de Morveaux, rejecting all existing ideas before him, proposed his theory: electrified cloud conducts electricity better... And Nolle put forward the idea that water evaporates faster when it is electrified, and reasoned that this should increase the cold somewhat, and also suggested that steam could be a better conductor of heat if it was electrified. Guyton criticized Jean André Monge and wrote: it is true that electricity enhances evaporation, but electrified droplets should repel each other, and not merge into large hailstones. The electrical theory of hail was proposed by another famous physicist, Alexander Volta. In his opinion, electricity was not used as the root cause of the cold, but to explain why hailstones remain suspended for so long that they have time to grow. Cold occurs as a result of the very rapid evaporation of clouds, aided by powerful sunlight, thin dry air, the ease of vaporization of the bubbles from which clouds are made, and the alleged effect of electricity to aid vaporization. But how do hailstones stay in the air for enough time? According to Volta, this reason can only be found in electricity. But how?

In any case, by the 20s of the XIX century. there is a general belief that the combination of hail and lightning means only that both of these phenomena occur under the same weather conditions. This was the opinion of von Buch, clearly expressed in 1814, and in 1830, Denison Olmsted of Iel emphatically asserted the same. From this time on, the theories of hail were mechanical and were based more or less firmly on the concept of ascending air currents. According to Ferrel's theory, each hailstone can fall and rise several times. By the number of layers in the hailstones, which sometimes can be up to 13, Ferrel judges the number of revolutions made by the hailstone. The circulation continues until the hailstones become very large. According to his calculations, the ascending current at a speed of 20 m / s is able to maintain a hail of 1 cm in diameter, and this speed for tornadoes is still quite moderate.

There are a number of relatively new scientific studies devoted to the mechanism of hail formation. In particular, they argue that the history of the formation of the city is reflected in its structure: a large hailstone, cut in half, is like an onion: it consists of several layers of ice. Sometimes hailstones resemble a layer cake, where ice and snow alternate. And there is an explanation for this - using such layers, you can calculate how many times a piece of ice made a wandering from rain clouds into the supercooled layers of the atmosphere. It's hard to believe: a hail weighing 1-2 kg can still jump up to a distance of 2-3 km? Layering of ice (hailstones) may appear on different reasons... For example, the difference in pressure in the environment will cause this phenomenon. And, in general, what does snow have to do with it? Is it snow?

In a recent website, Professor Yegor Chemezov puts forward his idea and tries to explain the formation of large hail and its ability to remain in the air for several minutes with the appearance of a "black hole" in the cloud itself. In his opinion, the hail takes negative charge... The greater the negative charge of an object, the lower the concentration of ether (physical vacuum) in this object. And the lower the concentration of ether in a material object, the more antigravity it possesses. According to Chemezov, a black hole is a good hailstone trap. As soon as lightning flashes, the negative charge is extinguished and hailstones begin to fall.

Analysis of world literature shows that in this area of ​​science there are many shortcomings and often speculation.

At the end of the All-Union conference in Minsk on September 13, 1989 on the topic "Synthesis and research of prostaglandins", we with the staff of the institute returned by plane from Minsk to Leningrad late at night. The stewardess reported that our plane was flying at an altitude of 9 km. We watched with pleasure the monstrous sight. Below us, at a distance of about 7-8 km(just above the surface of the earth) as if a terrible war was going on. These were powerful lightning discharges. And above us the weather is clear and the stars are shining. And when we were over Leningrad, we were told that an hour ago hail and rain fell into the city. With this episode, I want to note that hailstone lightning often flashes closer to the ground. For the occurrence of hail and lightning, it is not necessary to raise the flow of cumulonimbus clouds to a height of 8-10 km. And there is absolutely no need to cross the clouds above the zero isotherm.

Huge ice blocks form in the warm layer of the troposphere. This process does not require subzero temperatures and high altitudes. Everyone knows that hail does not occur without thunderstorms and lightning. Apparently, for the formation of an electrostatic field, collision and friction of small and large crystals are not necessary hard ice, as it is often written about, although the friction of warm and cold clouds in a liquid state (convection) is sufficient for this phenomenon to occur. It takes a lot of moisture to form a thundercloud. At the same relative humidity warm air contains much more moisture than cold. Therefore, thunderstorms and lightning usually occur during warm seasons - spring, summer, autumn.

The mechanism of formation of the electrostatic field in the clouds also remains open question... There are many assumptions on this issue. In one of the recent reports, in the ascending currents of moist air, along with uncharged nuclei, positively and negatively charged nuclei are always present. Moisture condensation may occur on any of them. It has been established that condensation of moisture in the air first begins on negatively charged nuclei, and not on positively charged or neutral nuclei. For this reason, negative particles accumulate in the lower part of the cloud, and positive ones in the upper part. Consequently, a huge electric field is created inside the cloud, the intensity of which is 10 6 -10 9 V, and the current strength is 10 5 3 10 5 A . Such a strong potential difference ultimately leads to a powerful electrical discharge. A lightning strike can last 10 -6 (one millionth) seconds. When lightning strikes, colossal heat energy is released, and the temperature at the same time reaches 30,000 o K! This is about 5 times the temperature of the Sun's surface. Of course, particles of such a huge energy zone should exist in the form of plasma, which, after a lightning discharge, by recombination, are converted into neutral atoms or molecules.

What could this awful warmth lead to?

Many people know that with a strong lightning discharge, neutral molecular oxygen in the air is easily converted into ozone and its specific smell is felt:

2O 2 + O 2 → 2O 3 (1)

In addition, it was found that even chemically inert nitrogen reacts with oxygen simultaneously under these harsh conditions, forming mono - NO and nitrogen dioxide NO 2:

N 2 + O 2 → 2NO + O 2 → 2NO 2 (2)

3NO 2 + H 2 O → 2HNO 3 ↓ + NO (3)

The resulting nitrogen dioxide NO 2, in turn, combining with water, turns into nitric acid HNO 3, which falls to the ground as part of the sediment.

Previously, it was believed that table salt (NaCl), carbonates of alkali (Na 2 CO 3) and alkaline earth (CaCO 3) metals contained in cumulonimbus clouds react with nitric acid, and ultimately nitrates (nitrate) are formed.

NaCl + HNO 3 = NaNO 3 + HCl (4)

Na 2 CO 3 + 2 HNO 3 = 2 NaNO 3 + H 2 O + CO 2 (5)

CaCO 3 + 2HNO 3 = Ca (NO 3) 2 + H 2 O + CO 2 (6)

Saltpeter mixed with water is a refrigerant. Given this premise, Gassendi developed the idea that the upper layers of the air are cold, not because they are far from the heat source reflected from the ground, but because of the "nitrogenous corpuscles" (saltpeter), which are very numerous there. In winter there are fewer of them, and they only generate snow, but in summer there are more of them, so hail can form. Subsequently, this hypothesis was also criticized by contemporaries.

What can happen to water under such harsh conditions?

There is no information about this in the literature.... By heating to a temperature of 2500 ° C or by passing a constant electric current at room temperature, it decomposes into its constituent components, and the thermal effect of the reaction is shown in the equation (7):

2H 2 O (f)→ 2H 2 (G) + O 2 (G) ̶ 572 kj(7)

2H 2 (G) + O 2 (G) → 2H 2 O (f) + 572 kj(8)

The decomposition reaction of water (7) is an endothermic process, and energy must be introduced from outside to break covalent bonds. However, in this case, it comes from the system itself (in this case, water polarized in an electrostatic field). This system resembles an adiabatic process, during which there is no heat exchange between the gas and the environment, and such processes occur very quickly (lightning discharge). In a word, during the adiabatic expansion of water (decomposition of water into hydrogen and oxygen) (7), it is consumed internal energy, and therefore begins to cool itself. Of course, with a lightning strike, the balance is completely shifted to right side, and the resulting gases - hydrogen and oxygen - by the action of an electric arc instantly react with a roar ("explosive mixture") with the formation of water (8). This reaction is easy to carry out in a laboratory setting. Despite the decrease in the volume of the reacting components in this reaction, a strong rumble is obtained. At speed feedback according to Le Chatelier's principle, the high pressure obtained as a result of reaction (7) favorably acts. The fact is that the direct reaction (7) must also go with a strong roar, since from the liquid aggregate state water instantly forms gases (Most authors attribute this to strong heating and expansion in or around the air channel created by a strong lightning discharge). It is possible that, therefore, the sound of thunder is not monotonous, that is, it does not resemble the sound of an ordinary explosive or a weapon. First, decomposition of water occurs (first sound), followed by the addition of hydrogen with oxygen (second sound). However, these processes occur so quickly that not everyone can distinguish them.

How is hail formed?

In the event of a lightning strike due to receiving huge amount heat, water through the channel of the lightning discharge or around it intensively evaporates, as soon as the flashing of lightning stops, it begins to cool down strongly. According to the well-known law of physics strong evaporation leads to a cold snap... It is noteworthy that heat during a lightning strike is not introduced from the outside, on the contrary, it comes from the system itself (in this case, the system - water polarized in an electrostatic field). The evaporation process consumes the kinetic energy of the polarized water system itself. In this process, strong and instant evaporation results in a strong and rapid solidification of water. The stronger the evaporation, the more intensively the water solidification process is realized. For such a process, it is not necessary for the ambient temperature to be below freezing. When lightning strikes, various types hailstones, differing in size. The magnitude of the hailstone depends on the power and intensity of the lightning. The more powerful and intense the lightning, the larger the hailstones are. Usually hailstone sediment will quickly stop as soon as the lightning stops flashing.

Processes of a similar type operate in other spheres of Nature. Here are some examples.

1. Refrigeration systems work according to the indicated principle. That is, artificial cold (sub-zero temperatures) is formed in the evaporator as a result of the boiling of a liquid refrigerant, which is fed there through a capillary tube. Due to the limited capacity of the capillary tube, refrigerant enters the evaporator relatively slowly. The boiling point of the refrigerant is usually about - 30 o C. Getting into the warm evaporator, the refrigerant boils instantly, strongly cooling the walls of the evaporator. Refrigerant vapors from boiling pass from the evaporator to the suction pipe of the compressor. By pumping gaseous refrigerant from the evaporator, the compressor pumps it under high pressure into the condenser. The gaseous refrigerant in the condenser under high pressure, while cooling, gradually condenses, changing from a gaseous to a liquid state. Again, liquid refrigerant from the condenser is fed through a capillary tube to the evaporator, and the cycle is repeated.

2. Chemists are well aware of the production of solid carbon dioxide (CO 2). Carbon dioxide is usually transported in steel cylinders in a liquefied liquid aggregate phase. When gas is slowly passed from the cylinder at room temperature, it goes into gaseous state if his release intensively, then it immediately goes into a solid state, forming "snow" or "dry ice" with a sublimation temperature from -79 to -80 o C. Intensive evaporation leads to solidification of carbon dioxide, bypassing the liquid phase. Obviously, the temperature inside the cylinder is above zero, but the solid carbon dioxide (“dry ice) released in this way has a sublimation temperature of about -80 ° C.

3. Another important example related to this topic. Why does a person sweat? Everyone knows that in normal conditions or during physical exertion, as well as with nervous excitement, a person sweats. Sweat is a liquid secreted by sweat glands and contains 97.5 - 99.5% water, a small amount of salts (chlorides, phosphates, sulfates) and some other substances (from organic compounds - urea, urate salts, creatine, sulfuric acid esters). True, excessive sweating may indicate the presence of serious illnesses. There may be several reasons: colds, tuberculosis, obesity, cardiovascular disorders, etc. However, the main thing is sweating regulates body temperature... Sweating increases in hot and humid climates. We usually break out in sweat when we are hot. The higher the ambient temperature, the more we sweat. The body temperature of a healthy person is always 36.6 ° C, and one of the methods of maintaining such normal temperature is sweating. Through the enlarged pores, intensive evaporation of moisture from the body occurs - a person sweats a lot. And evaporation of moisture from any surface, as mentioned above, helps to cool it. When the body is threatened with dangerous overheating, the brain triggers the mechanism of perspiration, and the sweat evaporating from our skin cools the surface of the body. This is why a person sweats in the heat.

4. In addition, water can also be turned into ice in a conventional glass laboratory apparatus (Fig. 1), with reduced pressures without external cooling (at 20 ° C). It is only necessary to connect a fore-vacuum pump with a trap to this installation.

Figure 1. Vacuum distillation unit

Figure 2. Amorphous structure inside the hailstone

Figure 3. Blocks of hailstones formed from small hailstones

In conclusion, I would like to touch on a very important question concerning the layering of hailstones (Fig. 2-3). What is the reason for the turbidity in the structure of the hailstone? It is believed that in order to carry a hailstone with a diameter of about 10 centimeters through the air, the ascending jets of air in a thundercloud must have a speed of at least 200 km / h, and thus snowflakes and air bubbles are included in it. This layer looks cloudy. But if the temperature is higher, then the ice freezes more slowly, and the included snowflakes have time to melt, and the air evaporates. Therefore, it is assumed that such a layer of ice is transparent. According to the authors, the rings can be used to trace which layers of the cloud the hailstone has visited before falling to the ground. From fig. 2-3 it is clearly seen that the ice of which the hailstones are composed is indeed heterogeneous. Almost every hailstone consists of a clean and in the center muddy ice... The opacity of ice can be caused for various reasons. In large hailstones, layers of transparent and opaque ice sometimes alternate. In our opinion, the white layer is responsible for the amorphous, and the transparent layer is the crystalline form of ice. In addition, the amorphous aggregate form of ice is obtained by extremely rapid cooling liquid water(at a rate of about 10 7 ° K per second), as well as a rapid increase in the pressure of the environment, so that the molecules do not have time to form a crystal lattice. In this case, this occurs as a lightning discharge, which fully corresponds to favorable conditions the formation of metastable amorphous ice. Huge lumps weighing 1-2 kg from fig. 3 it can be seen that they formed from clusters of relatively small hailstones. Both factors show that the formation of the corresponding transparent and opaque layers in the section of the hailstone is due to the effect of extremely high pressures generated during a lightning discharge.

Conclusions:

1. Without a lightning strike and a strong thunderstorm, hail does not occur, a thunderstorms are without hail. The storm is accompanied by hail.

2. The reason for the formation of hail is the generation of an instant and huge amount of heat during a lightning strike in cumulonimbus clouds. The resulting powerful heat leads to strong evaporation of water in the lightning discharge channel around it. Strong evaporation of water is accomplished by its rapid cooling and the formation of ice, respectively.

3. This process does not require the transition of the zero isotherm of the atmosphere, which has negative temperature, and can easily occur in the low and warm layers of the troposphere.

4. The process is essentially close to the adiabatic process, since the generated heat energy is not introduced into the system from the outside, and it comes from the system itself.

5. Powerful and intense lightning discharge provides conditions for the formation of large hailstones.

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