Lowest temperature, maximum precipitation and other weather records

Meteorology books often describe the Earth's atmosphere as a vast ocean of air in which we all live. Various diagrams depict our planet surrounded by a huge atmospheric sea several hundred kilometers high, divided into several different layers. But the layer of our atmosphere that supports all life is actually extremely thin—just over 5 km thick. The part of our atmosphere that can be measured with some degree of accuracy rises to about 40 kilometers. Moreover, it is almost impossible to give a precise answer about where the atmosphere ultimately ends; Somewhere between 400 and 500 km there is an undefined region where the air gradually thins and eventually dissolves into the vacuum of space.

So the layer of air surrounding our planet is not that big after all. As one famous meteorologist so eloquently put it: “The Earth is not suspended in a sea of ​​air—it is suspended in a sea of ​​space, and there is an extremely thin layer of gas on its surface.”

And this gas is our atmosphere.

If a person climbs a high mountain, such as Mauna Kea on the island of Hawaii, whose peak reaches 4206 meters above sea level, there is a high risk of suffering from altitude sickness (hypoxia). Before reaching the summit, visitors stop at an intermediate camp located at an altitude of 2804 m, where they must acclimatize to the altitude before continuing further up the mountain. “Well, of course,” you might say, “everyone knows that the amount of oxygen available at such high altitudes is significantly less compared to what is available at sea level.”

But in making such a statement, you are mistaken!

In fact, 21% of the Earth's atmosphere consists of life-giving oxygen (78% is nitrogen, and the remaining 1% is other gases). And this ratio in proportions is almost the same both at sea level and high in the mountains.

The big difference is not the amount of oxygen present, but rather its density and pressure.

Air is often compared to the ocean using the term "ocean of air", and this is true because we are all literally floating in the air. Now imagine this: a tall plastic bucket is filled to the brim with water. Now make a hole in the top of the bucket. The water will drain slowly. Now make another hole at the bottom near the bottom. What will happen? Water will rapidly flow out from the bottom hole in a strong stream. The reason is the difference in pressure. The pressure exerted by the weight of the water below at the bottom of the bucket is greater than at the top, so the water is “squeezed out” more strongly from the hole below.

Likewise, the pressure of all the air above us is the force that pushes air into our lungs, thereby delivering oxygen into the bloodstream. Once this pressure is reduced (for example, when we climb a high mountain), less air enters the lungs, therefore less oxygen reaches our bloodstream, resulting in hypoxia; again, not due to a decrease in the amount of available oxygen, but due to a decrease in atmospheric pressure.

What is atmospheric pressure?

Atmospheric pressure, also called barometric pressure, is the pressure of the gaseous shell of our planet, the atmosphere, acting on all objects located in it, as well as on the earth's surface. Pressure corresponds to the force acting in the atmosphere per unit area. In a stationary atmosphere at rest, the pressure is equal to the ratio of the weight of the overlying air column to its cross-sectional area.

Simply put, this is the force with which the air around us acts on the surface of the Earth and objects.

Atmospheric pressure is expressed in several different systems of units: millimeters (or inches) of mercury, dynes (dyn) per square centimeter, millibars (mb), standard atmosphere, or pascals (Pa). Standard sea level pressure is defined as 760 mmHg (29.92 in), 1013.25 x 103 dynes per cm2, 1013.25 millibars, one standard atmosphere, or 101.325 kilopascals. 1 mmHg corresponds to approximately 133 Pa.

Why does atmospheric pressure occur?

Many experiments have proven that air is not weightless. The Earth's gravitational force acts on the air, which contributes to the formation of pressure.

The mass of air around the globe is not the same. Therefore, the level of atmospheric pressure also fluctuates. Areas with more air mass experience higher pressure. If there is less air (in such cases it is also called rarefied), then the pressure is lower.

Why does the weight of the atmosphere change? The secret of this phenomenon lies in the heating of air masses. The fact is that the air is heated not directly from the sun's rays, but due to heating from the earth's surface. Near it, the air heats up, expands and, becoming lighter, rises. At this time, the cooled flows become heavier and go down. This process happens constantly. Air moves from areas of high pressure to areas of low pressure. The result is wind, which has a great influence on weather and climate.

Atmospheric pressure measurement

To measure atmospheric pressure, meteorologists use a barometer.

There are two types of barometers:

• liquid;
• mechanical (aneroid barometer).

Liquid barometers are filled with mercury. This device was invented by the Italian scientist Evangelista Torricelli. In 1643 he proved that the atmosphere could be weighed using a column of mercury. This device was the very first barometer. The open end of the glass tube is placed in an open bowl of mercury. Atmospheric pressure forces the mercury to rise up the tube. At sea level, the mercury will rise (on average) to a height of 760 millimeters.

Why not use water instead of mercury? The fact is that mercury is 13.6 times denser than water. Atmospheric pressure can hold in place a vertical column of water approximately 13.6 times higher than mercury. And in order to make a water barometer, you will need a glass tube more than 10 m long!

Evangelista Torricelli - Italian mathematician and physicist, student of Galileo. Known as the author of the concept of atmospheric pressure and the successor of Galileo's work in the development of new mechanics.

On the other hand, mercury is the heaviest substance that remains liquid at ordinary temperatures. This makes the tool more convenient to use.

Aneroid barometers are more common . The design of such a device includes a metal box with rarefied air inside. When the pressure drops, the box expands. As the pressure increases, the box compresses and acts on the attached spring. The spring moves the arrow, which shows the pressure level on the scale.

Increase and decrease in pressure

When the pressure exceeds 760 mmHg. Art., it is called elevated, and when the level is less than normal - reduced.

Over the course of 24 hours, several changes in atmospheric pressure occur. In the morning and evening it rises, and after 12 noon and at night it decreases. This occurs due to the fact that the air temperature changes and, accordingly, its flows move.

In winter, the highest atmospheric pressure is observed over the mainland of the Earth, because the air here has a low temperature and is very dense. In summer, the opposite situation is observed - there is minimal pressure.

On a more global scale, pressure also depends on temperature. The Earth's surface heats unevenly: the planet has a geoid (rather than perfectly round) shape and revolves around the Sun. Some parts of the planet are heating up more, others less. Because of this, atmospheric pressure is distributed zonally over the surface of the planet.

Atmospheric pressure belts

There are 3 zones where low pressure prevails, and 4 zones where high pressure prevails. The equatorial zone warms up the most, so light warm air rises and low pressure forms at the surface.

At the poles, the opposite is true: cold air settles down, so high pressure is recorded here. If you look at the pattern of pressure distribution over the surface of the planet, you will notice that belts of low and high pressure alternate.

In addition, you need to remember about the uneven heating of both hemispheres of the Earth throughout the year. This leads to some displacement of the low and high pressure belts. In summer they move to the north, and in winter - to the south.

Atmospheric pressure normal for humans

Normal atmospheric pressure is 760 mmHg. Art. or 101,325 Pa at 0 ℃ at sea level (45° latitude). In this case, each square centimeter of the earth's surface is affected by the atmosphere with a force of 1.033 kg. A column of mercury 760 mm high balances the mass of this column of air.

Almost all of the Maldives, an island nation in the Indian Ocean, is located almost at sea level. This makes the Maldives the "lowest-lying" country in the world, under constant threat from rising sea levels. The country hopes to buy land in India, Sri Lanka or Australia to be able to evacuate residents of the Maldives if the islands begin to go under water.

The aforementioned Torricelli also noticed during the experiment that when the flask is filled with mercury, an unfilled space remains in its upper part - emptiness. Over time, this phenomenon began to be called “Torricelli void.” Then the scientist did not yet know that during his experiment he created a vacuum - that is, a space free of any substances.

At a standard pressure of 760 mmHg. Art. the person feels most comfortable. The air presses on a person with a force of about 16 tons, but we do not notice it. Why don't we feel this pressure?

The fact is that there is pressure inside our body too. Not only people, but also representatives of the animal world have adapted to atmospheric pressure. Each organ was formed and developed under the influence of this force. When the atmosphere acts on a body, this force is evenly distributed over the entire surface. Thus, our internal pressure is balanced with external pressure, and we do not feel it.

Normal atmospheric pressure should not be confused with climate norm. Each region has its own standards for a certain time of year. For example, in Vladivostok, the average annual atmospheric pressure is almost equal to the norm - 761 mm Hg. Art.

But in settlements located in mountainous areas (for example, in Tibet), the pressure is usually much lower - 413 mm Hg. Art. This is associated with an altitude of about 5000 m.

Panoramic view of the city of Puno next to Lake Titicaca, in the Peruvian Andes, near Bolivia. Puno is the capital of the province of Puno with a population of approximately 150,000 people. The city is located at an altitude of 3812 meters above sea level. Atmospheric pressure at this altitude is about 483 mmHg. Art.

What is the maximum blood pressure that can be withstood?

Any deviation of blood pressure from the norm can result in significant complications. It is important to know how much pressure a person can withstand. It is impossible to answer this question accurately. All people have certain characteristics of the body. They react differently to blood pressure deviations. Experts say that an increase of 25-30 units can already be regarded as a potential danger.

Hypertension can be diagnosed in a person whose blood pressure level exceeds 140/95. When blood pressure increases by 20 units, the patient experiences a whole range of unpleasant symptoms. The greatest danger is posed by a spontaneous and rapid increase in blood pressure, but small changes are usually short-lived.

Headache and high blood pressure are the main symptoms of hypertension

Experts note that it is rare to encounter patients whose upper blood pressure levels have reached 300 units. Not every person can withstand this level. Usually, at such rates, death occurs.

Experts say that the maximum blood pressure that a person can withstand is 260/140. At higher rates, many patients die or have irreversible consequences. This condition may lead to:

• heart failure;
• ischemic stroke;
• apoplexy.

To prevent irreversible consequences, you need to call a doctor as soon as possible when the first symptoms of increased blood pressure appear.

The influence of atmospheric pressure on humans

For a long time, medicine did not recognize the connection between weather events and health. Only over the past 50 years, thanks to a comprehensive study of the influence of weather conditions on the human body, it has been proven that atmospheric pressure and human health are closely related, and people react to any weather changes with complications in their well-being. The situation when weather conditions affect the physical state of the human body is called meteopathy.

Meteopaths are people whose body reacts to even minimal deviations of atmospheric pressure from the norm. They also include people with certain chronic diseases (in particular, cardiovascular, nervous system, etc.).

The atmospheric pressure fluctuates within 30 mm Hg per year. Art. During the day, values ​​can fluctuate from 1 to 3 mmHg. A healthy person does not feel these changes, but weather-dependent people with any health problems can feel these deviations.

Hypertension and hypotension are two main diseases characterized by meteorological dependence.

High atmospheric pressure is extremely unsafe for hypertensive patients and people with heart disease. Anyone who has hypertension and sensitivity to weather changes will have to deal with the following symptoms: the heart beats faster, against the background of which blood pressure (BP) rises; the skin begins to turn red; weakness is observed; There is noise in the ears, spots in front of the eyes, and pulsation in the head.

People with hypertension in old age feel strongly the weather changes. Their body is weakened by age-related changes and accumulated diseases, resulting in a risk of hypertensive crisis, damage to the heart and blood vessels.

A drop in atmospheric pressure primarily affects the health of people with hypotension and respiratory pathologies. The percentage of carbon dioxide in the air increases, and oxygen, on the contrary, decreases. Such changes in weather conditions due to a lack of oxygen in hypotensive patients cause ailments: blood circulation slows down and the pulse weakens, blood flows worse to the organs, blood pressure drops; breathing becomes difficult; drowsiness and fatigue, dizziness and nausea appear; intracranial pressure increases, against the background of this, spasms occur that turn into headaches.

The dependence of people’s well-being on atmospheric pressure concerns not only surges in blood pressure. In people with mental disorders, the manifestation of obsessive states, fears and various phobias increases.

With joint diseases, the likelihood of pain attacks increases at the sites of fractures and where problems exist.

Absolutely anyone, even a healthy person, will feel significant deviations from the norm. This applies to both high and low pressure.

The effect of low atmospheric pressure on the well-being of a person located, for example, in the mountains, is manifested in increased breathing and heart rate, headaches, asthma attacks and nosebleeds. Symptoms disappear as the person gets used to the surrounding conditions. There is often a need for medical care for people who have signs of oxygen deprivation.

Climbers, when climbing mountain peaks, are forced to take oxygen cylinders with them in order to avoid death from lack of oxygen.

Climbing Everest

With elevated blood pressure, a person's pulse slows down and respiratory function is inhibited. In addition, blood clotting increases and intestinal walls contract. The influence of external pressure on a person’s well-being increases in proportion to the distance to which the person descends. People who work at depth are most susceptible to the effects of high pressure. The amount of dissolved gases in the blood reaches its maximum value, performance and concentration increase. However, at the same time, a large amount of oxygen has a toxic effect and provokes the occurrence of lung diseases. Raising workers from depth is carried out in a special way in accordance with accepted techniques. If the rate of ascent is disrupted, gas bubbles clog the blood vessels and death can occur.

How to get a pressure of 100,000 atmospheres?

Many amateurs have access to a fairly simple method of obtaining truly amazing pressures.
Why this is needed and how it can be used is in this article. Since the first days of its discovery, the electrohydraulic effect has been and remains a constant source of the birth of many progressive technological processes, which are now widely used throughout the world.
This determines its enduring significance and the ever-increasing interest shown in it in various branches of science, technology and economics. This video uses the explosive method.
However, in this application, the electro-hydraulic method is more efficient and cheaper. In the first half of the 20th century, the molding of many large body parts (including car body parts) took place using the explosive method. The essence of which is described in sufficient detail in this video:

However, in the future, the new discovery gave scientists and industry unique opportunities for processing materials.

When a specially formed pulsed high-voltage electrical discharge is created inside a volume of liquid, ultra-high pressures develop in the zone of the latter, which can be widely used for practical purposes—for example, for the first time in 1950, L. A. Yutkin formulated the new method he proposed for transforming electrical energy into mechanical energy. , called by the author the electrohydraulic effect (EHE).

For the last 30 years of his life, L. A. Yutkin worked actively and fruitfully in the field of electrohydraulics. During this period, he developed the theoretical foundations of the phenomenon, identified process control methods that significantly expand the capabilities and ensure high efficiency of electrohydraulic processing of materials, proposed more than 200 methods and devices for the practical application of EGE, received 140 patents for inventions, and published 50 publications on electrohydraulics. Under his leadership, the fundamental designs of industrial installations for various purposes were developed, search work was carried out, devices and technological processes were prepared for implementation and partially implemented, allowing for the effective use of the electro-hydraulic effect in many areas of the national economy.

❒ Electrohydraulic effect (EHE)

- a new industrial method of converting electrical energy into mechanical energy, carried out without intermediate mechanical links, with high efficiency.
The essence of this method is that when a specially formed pulsed electric (spark, brush and other forms) discharge is carried out inside a volume of liquid located in an open or closed vessel, ultra-high hydraulic pressures arise around the zone of its formation, capable of performing useful mechanical work and accompanied by a complex of physical and chemical phenomena. The electrohydraulic effect is characterized by a mode of energy release at the active resistance of the circuit, close to critical, i.e. when 1/C The
basis of the electrohydraulic effect is the previously unknown phenomenon of a sharp increase in hydraulic and hydrodynamic effects and the amplitude of the impact action when implementing a pulsed electric discharge in an ion-conducting liquid subject to the maximum shortening of the pulse duration, the steepest pulse front and the pulse shape close to aperiodic.

It follows that the main factors determining the occurrence of the electrohydraulic effect are the amplitude, slope of the front, shape and duration of the electric current pulse. The duration of the current pulse is measured in microseconds, so the instantaneous power of the current pulse can reach hundreds of thousands of kilowatts. The steepness of the front of the current pulse determines the expansion rate of the discharge channel. When a voltage of several tens of kilovolts is applied to the discharge electrodes, the amplitude of the current in the pulse reaches tens of thousands of amperes.

❒ All this causes a sharp and significant increase in pressure in the liquid, which, in turn, causes a powerful mechanical action of the discharge.

The implementation of the electrohydraulic effect is associated with the relatively slow accumulation of energy in the power source and its almost instantaneous release in a liquid medium.

The main operating factors of the electrohydraulic effect are high and ultra-high pulsed hydraulic pressures, leading to the appearance of shock waves at sonic and supersonic speeds; significant pulsed movements of liquid volumes occurring at speeds reaching hundreds of meters per second; powerful pulsed cavitation processes capable of covering relatively large volumes of liquid; infra- and ultrasonic radiation; mechanical resonance phenomena with amplitudes that allow mutual peeling of multicomponent solids from each other; powerful electromagnetic fields (tens of thousands of oersteds); intense pulsed light, thermal, ultraviolet, and x-ray radiation; pulsed gamma and (at very high pulse energies) neutron radiation; multiple ionization of compounds and elements contained in a liquid.

All these factors make it possible to exert a wide variety of physical and chemical effects on the liquid and objects placed in it. Thus, shock movements of liquid that occur during the development and collapse of cavitation cavities are capable of destroying non-metallic materials and causing plastic deformations of metal objects placed near the discharge zone.

Powerful infra- and ultrasonic vibrations accompanying the electrohydraulic effect additionally disperse already crushed materials, cause resonant destruction of large objects into individual crystalline particles, and carry out intensive chemical processes of synthesis, polymerization, and breaking of sorption and chemical bonds. The electromagnetic fields of the discharge also have a powerful influence, both on the discharge itself and on the ionic processes occurring in the surrounding liquid. Under their influence, various physical and chemical changes can occur in the processed material.

The concept of liquid as a medium for the occurrence of electrohydraulic shocks should be expanded to all elastic and even solid (for example, bulk) materials.

The form of discharge that causes the occurrence of pulsed pressures can be very diverse: spark, brush, without brushes at all (the so-called pulsed electric wind).

The high efficiency of the electrohydraulic effect, as well as the unique capabilities of the electrohydraulic effect, are the basis for the widespread use of the electrohydraulic effect in all areas of the economy.

Do-it-yourselfers also keep up with the pundits. For example:

They make rockets on this effect

Trying to stamp metal

Splashing water

Yutkin studied the phenomena occurring in the zone of a high-voltage spark discharge in a liquid medium.
At the initial stage, these studies confirmed the existing data that such a discharge easily occurs only in dielectric liquids, and in liquids with ionic conductivity it occurs only in cases of a very short spark gap and is always accompanied by abundant gas and vapor formation. The mechanical effect of a liquid on objects placed near the discharge channel, obtained according to the traditional scheme with a direct connection of a capacitor to the discharge gap in the liquid, is practically negligible for liquids with ionic conductivity and is relatively noticeable only in the environment of liquid dielectrics. It is determined by very insignificant pressures inside the vapor-gas bubble that arises around the discharge zone. The hydraulic pulses created in the liquid have a flat front and a significant duration of flow, while they have little power.

In this regard, it was necessary to find conditions in which the action of hydraulic impulses could be sharply enhanced. To do this, it was necessary to reduce the thickness of the vapor-gas shell and shorten the duration of the discharge during which it is created. At the same time, it was necessary to increase the power of a single pulse.

It turned out to be possible to solve this problem by developing a basic electrical circuit that ensured the supply of current to the working gap in the form of a short pulse using an instantaneous “shock” connection of an energy storage device.

For this purpose, the author introduced a forming air spark gap into the electrical circuit, which made it possible in liquids with ionic conductivity to change the nature of the spark discharge and sharply enhance its mechanical effect.

An additional forming air gap allows you to accumulate a given amount of energy with a pulsed supply of it to the main gap, significantly reduce the pulse duration and prevent the occurrence of oscillatory processes, create a steep pulse front, eliminating the possibility of transition to an arc discharge; obtain, at a given main interelectrode gap, any current and voltage values ​​permissible for the power source used; by adjusting the length of the forming gap, change the shape of the pulse and the nature of the discharge in the main working gap in the liquid. It was the forming gap that sharpened the current pulse, which made it possible to move to voltages much higher than the breakdown voltage of the working gap in the liquid.

Thus, to create electro-hydraulic shocks, the following scheme was proposed:

Figure 1
Including a power source with a capacitor as an electrical energy storage device.

The voltage on the capacitor rises to a value at which spontaneous breakdown of the air forming gap occurs, and all the energy stored in the capacitor is instantly supplied to the working gap in the liquid, where it is released in the form of a short electrical pulse of high power. Next, the process, at a given capacitance and voltage, is repeated with a frequency depending on the power of the supply transformer.

The author also proposed a scheme with two forming gaps. As it turned out, the introduction of two forming spark gaps makes it possible to obtain a slight increase in the steepness of the pulse front, and most importantly, makes the circuit symmetrical, more controllable and safe to use:

Figure 2
But, since the increase in the steepness of the pulse front is small, and the complexity of manufacturing the circuit is increased, it is almost never used in practice.

Subsequently, the author proposed other schemes.

However, the forming gap (in its various modifications, for example, in the form of an ignitron) is used in all modern electro-hydraulic power plants.

The possibility of wide variation in the parameters of the electrical circuit that reproduces the electrohydraulic effect was established experimentally.

This gave rise to the introduction of the concept of “operating mode” of the power plant, meaning by this the values ​​of the main parameters of the circuit: capacitance and voltage.

❒ Three main modes have been identified:

• hard: U>=;50kV; C<=0.1 µF;
• average: 20kV<=U<=50kV; 0.1 µF<=С<=1.0 µF;
• soft: U<=20 kV; C>=1.0 µF.

Method for increasing the efficiency of the electrohydraulic effect:

Electrohydraulic shock, even in very large volumes of liquid, causes the appearance of pressures of tens and hundreds of thousands of atmospheres, i.e., two to four orders of magnitude higher than the pressures in the discharge channel.
It is known that pressures in the liquid during electrohydraulic shocks arise due to the transfer of energy to the liquid from the discharge channel expanding in it at cosmic speed.

Figure 3
The basis that provides the diverse technological capabilities of the electrohydraulic effect is the method proposed in 1950 for producing ultra-long discharges in conductive liquids, carried out by limiting the active (i.e., in contact with the liquid) area of ​​the positive electrode while simultaneously increasing the active area of ​​the negative electrode. The method makes it possible to obtain the growth of streamers in conductive liquids over significant distances, due to which discharges with a large length and channel surface, capable of intensely releasing their energy into the surrounding space, arise. The author initially came to the conclusion about the possibility of obtaining such discharges as a result of logical reasoning.

The effect of water hammer can be enhanced only by creating all the conditions for the most efficient conversion of electrical energy into mechanical energy, bearing in mind that the spark is the instrument that transfers energy into the surrounding fluid. And since energy is transferred to the liquid through the surface of the spark discharge channel, it is obvious that the larger the surface, the greater the energy will be.

It turned out to be possible to create such conditions without complex and expensive devices and without changing the chemical composition of water due to changing the shape of the electrodes.

Indeed, with a sharp decrease in the active surface of the positive electrode in contact with water (through maximum insulation along its entire length, except for the front end) and a simultaneous sharp increase in the active surface of the negative electrode in water, a significant field asymmetry arises between the electrodes and, as a consequence, a special ionic atmosphere (mostly of the same sign), promoting intensive growth of the streamer in the liquid.

Using this method, discharges in a conducting liquid such as water become tens of times longer at equal pulse parameters and are carried out at a voltage of 100 kV with a gradient of about 1 kV/cm of the length of the working spark gap. With increasing voltage, the gradient decreases nonlinearly, which makes it possible to obtain multimeter discharges in water at voltages of several hundred kilovolts.

Thus, a simple decrease in the active surface of the positive electrode with a simultaneous sharp increase in the active surface of the negative electrode made it possible to completely solve all the problems, resulting in the usual small and weak spark discharge observed by T. Lane, D. Priestley, F. Früngel and other researchers water has turned into an ultra-long spark discharge, capable of easily transferring energy outward, thereby providing high mechanical efficiency of a new method of industrial transformation of electrical energy into mechanical energy.

Electrical circuits of current pulse generators for electrohydraulic devices

The current pulse generator (CPG) is designed to generate multiple repeating current pulses that reproduce the electrohydraulic effect.
The basic diagrams of GIT were proposed back in the 1950s and over the past years have not undergone significant changes, but their component equipment and level of automation have significantly improved. Modern GITs are designed to operate in a wide range of voltage (5-100 kV), capacitor capacitance (0.1-10000 μF), stored storage energy (10-106 J), and pulse repetition rate (0.1-100 Hz). The given parameters cover most of the modes in which electro-hydraulic installations for various purposes operate.

The choice of the GIT circuit is determined in accordance with the purpose of specific electro-hydraulic devices. Each generator circuit includes the following main blocks: power supply - transformer with rectifier; energy storage - capacitor; switching device - forming (air) gap; load - working spark gap. In addition, GIC circuits include a current-limiting element (this can be resistance, capacitance, inductance, or their combinations). In GIC circuits there may be several forming and working spark gaps and energy storage devices. The GIT is powered, as a rule, from an alternating current network of industrial frequency and voltage.

GIT works as follows. Electrical energy through the current-limiting element and the power supply enters the energy storage device - a capacitor. The energy stored in the capacitor with the help of a switching device - the air forming gap - is pulsedly transmitted to the working gap in the liquid (or other medium), on which the electrical energy of the storage device is released, resulting in an electro-hydraulic shock. In this case, the shape and duration of the current pulse passing through the discharge circuit of the GIT depend both on the parameters of the charging circuit and on the parameters of the discharge circuit, including the working spark gap. If for single pulses of special GITs the parameters of the charging circuit circuit (power supply) do not have a significant impact on the overall energy performance of electrohydraulic installations for various purposes, then in industrial GITs the efficiency of the charging circuit significantly affects the efficiency of the electrohydraulic installation.

The use of reactive current-limiting elements in GIT circuits is due to their ability to accumulate and then release energy into the electrical circuit, which ultimately increases efficiency.

The electrical efficiency of the charging circuit of a simple and reliable GIT circuit with a limiting active charging resistance (Fig. 4, a) is very low (30-35%), since the capacitors are charged in it by pulsating voltage and current. By introducing special voltage regulators (magnetic amplifier, saturation choke) into the circuit, it is possible to achieve a linear change in the current-voltage characteristics of the charge of a capacitive storage device and thereby create conditions under which energy losses in the charging circuit will be minimal, and the overall efficiency of the GIT can be increased to 90% .

To increase the total power when using the simplest GIT circuit, in addition to the possible use of a more powerful transformer, it is sometimes advisable to use a GIT having three single-phase transformers, the primary circuits of which are connected by a “star” or “delta” and are powered from a three-phase network. The voltage from their secondary windings is supplied to individual capacitors, which operate through a rotating forming gap to one common working gap - the spark gap in the liquid (Fig. 4, b).

When designing and developing GIT electrohydraulic installations, the use of the resonant mode of charging a capacitive storage device from an alternating current source without a rectifier is of significant interest. The overall electrical efficiency of resonant circuits is very high (up to 95%), and when used, there is an automatic significant increase in operating voltage. It is advisable to use resonant circuits when operating at high frequencies (up to 100 Hz), but this requires special capacitors designed to operate on alternating current. When using these circuits, it is necessary to comply with the well-known resonance condition:

where ω is the frequency of the driving EMF; L - circuit inductance; C is the circuit capacity.

Figure 4
A single-phase resonant GIT (Fig. 4, c) can have an overall electrical efficiency exceeding 90%. The GIT makes it possible to obtain a stable frequency of alternating discharges, optimally equal to either a single or double frequency of the supply current (i.e. 50 and 100 Hz, respectively) when powered with industrial frequency current. The use of the circuit is most rational when the power of the supply transformer is 15-30 kW. A synchronizer is introduced into the discharge circuit of the circuit - an air forming gap, between the balls of which there is a rotating disk with a contact that causes the forming gap to operate when the contact passes between the balls.

In this case, the rotation of the disk is synchronized with the moments of voltage peaks.

The circuit of a three-phase resonant GIT (Fig. 4, d) includes a three-phase step-up transformer, each winding on the high side of which operates as a single-phase resonant circuit for one common spark gap for all or for three independent working spark gaps with a common synchronizer for three forming gaps. This circuit makes it possible to obtain a discharge frequency equal to three times or six times the frequency of the supply current (i.e., 150 or 300 Hz, respectively) when operating at industrial frequency. The circuit is recommended for operation at GIT powers of 50 kW or more. The three-phase GIC circuit is more economical, since the charging time of a capacitive storage device (of the same power) is less than when using a single-phase GIC circuit. However, further increasing the rectifier power will be advisable only up to a certain limit.

The efficiency of the process of charging a capacitive storage device can be increased by using various circuits with filter capacitance. The GIT circuit with a filter capacitance and an inductive charging circuit of the working capacitance (Fig. 4, e) allows one to obtain almost any pulse alternation frequency when operating on small (up to 0.1 µF) capacitances and has an overall electrical efficiency of about 85%. This is achieved by the fact that the filter capacitance operates in an incomplete discharge mode (up to 20%), and the working capacitance is charged through an inductive circuit - a choke with low active resistance - during one half-cycle in an oscillatory mode, set by rotating the disk at the first forming interval. In this case, the filter capacity exceeds the working capacity by 15-20 times.

The rotating disks of the forming spark gaps sit on the same shaft and therefore the frequency of alternating discharges can be varied within a very wide range, maximally limited only by the power of the supply transformer. Transformers of 35-50 kV can be used in this circuit, since it doubles the voltage. The circuit can also be connected directly to a high-voltage network.

In the GIT circuit with a filter tank (Fig. 4, f), the alternate connection of the working and filter tanks to the working spark gap in the liquid is carried out using one rotating spark gap - the forming gap.

However, when such a GIT operates, the operation of the rotating spark gap begins at a lower voltage (when the balls approach each other) and ends at a higher voltage (when the balls move away) than that specified by the minimum distance between the balls of the spark gaps. This leads to instability of the main parameter of discharges—voltage, and, consequently, to a decrease in the reliability of the generator.

To increase the reliability of the operation of the GIT by ensuring the specified stability of the discharge parameters, a rotating switching device is included in the GIT circuit with a filter capacitance - a disk with sliding contacts for alternate preliminary current-free switching on and off of the charging and discharge circuits.

When voltage is applied to the generator charging circuit, the filter capacitance is initially charged. Then a rotating contact without current (and therefore without sparking) closes the circuit, a potential difference arises on the balls of the forming spark gap, breakdown occurs and the working capacitor is charged to the voltage of the filter capacitance. After this, the current in the circuit disappears and the contacts open again without sparking by rotating the disk. Next, the rotating disk (also without current and sparking) closes the contacts of the discharge circuit and the voltage of the working capacitor is applied to the forming spark gap, its breakdown occurs, as well as breakdown of the working spark gap in the liquid. In this case, the working capacitor is discharged, the current in the discharge circuit stops and, therefore, the contacts can be opened again by rotating the disk without sparking damaging them. Next, the cycle is repeated with a discharge frequency specified by the rotation speed of the switching device disk.

The use of this type of GIT makes it possible to obtain stable parameters of fixed ball spark gaps and to close and open the circuits of the charging and discharge circuits in a current-free mode, thereby improving all the performance and reliability of the power plant generator.

A power supply circuit for electro-hydraulic installations was also developed, allowing for the most efficient use of electrical energy (with a minimum of possible losses).

In known electrohydraulic devices, the working chamber is grounded and therefore part of the energy after the breakdown of the working spark gap in the liquid is practically lost, dissipating on the grounding. In addition, with each discharge of the working capacitor, a small charge (up to 10% of the original) remains on its plates.

Experience has shown that any electrohydraulic device can operate effectively according to a scheme in which the energy stored on one capacitor C1, passing through the forming gap of the FP, enters the working spark gap of the RP, where most of it is spent on performing the useful work of the electrohydraulic shock.
The remaining unspent energy goes to the second uncharged capacitor C2, where it is stored for later use (Fig. 5). After this, the energy of the second capacitor C2, charged to the required potential value, having passed through the forming gap of the FP, is discharged into the working spark gap of the RP and again the unused part of it now ends up on the first capacitor C1, etc. Figure 5
Alternate connection of each of the capacitors then charging, then into the discharge circuit is carried out by switch P, in which conductive plates A and B, separated by a dielectric, are alternately connected to contacts 1-4 of the charging and discharge circuits.

The oscillatory nature of the process ensures that the energy transfer during the discharge of one capacitor to another occurs with some excess (for the charged capacitor), which also has a positive effect on the operation of this circuit.

For some special cases, the indicated circuit can be constructed in such a way that after each recharging of the capacitor (for example, C1) with the energy “remaining” from the previous discharge of the capacitor C2 onto it, the subsequent discharge of the capacitor SU goes through the working gap to the ground, without going to recharge the capacitor C2. Such work will be equivalent to working in two modes at once, which can be effectively used in practice (in technological processes of crushing, destruction, grinding, etc.)

And for those who want to familiarize themselves with this effect in detail, it is recommended to find a book online and read (the article uses, in particular, materials from it): L.A. Yutkin - “Electrohydraulic effect and its application in industry.”

As can be seen from the variety of applications that are described in this book, this effect has useful applications in many areas and situations:

Below, you can watch a number of films about this wonderful effect and its inventor:

Cyclones and anticyclones

There are two main types of pressure systems in the atmosphere: cyclones and anticyclones. Cyclones and anticyclones are wind systems that have opposite characteristics.

A cyclone is a collection of winds circulating in a low pressure system. It rotates counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. It is usually associated with wet and stormy weather.

An anticyclone is a type of wind that circulates in a high pressure system. It rotates clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. It is usually associated with dry and clear weather.

In order to better understand how these two phenomena differ, let's look at them in more detail.

A cyclone is an area of ​​low pressure where air masses rise. This usually indicates bad weather, such as rain or clouds. Winds in cyclones blow counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. In a cyclone, air near the ground is forced toward the low-pressure center of the cyclone and then rises, expanding and cooling as it moves. As the rising air cools, it becomes more humid, leading to cloudiness and high humidity inside the cyclone. The main effects of tropical cyclones include heavy rain, strong winds, severe storm surges close to shore, and tornadoes. Destruction from a tropical cyclone, such as a hurricane or tropical storm, mainly depends on its intensity, size and location.

There are two types of cyclones:

1. Tropical cyclones . These cyclones that form over warm tropical oceans are also called tropical storms or tropical depressions. They are relatively small in size. However, they are characterized by enormous, destructive wind power.

The main tropical cyclone basins include the North Atlantic (including the Caribbean), the eastern Pacific, the western Pacific, the northern Indian Ocean, the southwestern Indian Ocean, the southern Pacific and the Australian region. Typically, tropical cyclones develop between 5 and 30 degrees latitude, as they require ocean water at a temperature of 27°C or so to form.

The terminology associated with tropical cyclones is quite confusing because people call these dangerous storms by different names in different parts of the world. In the North Atlantic and Caribbean, as well as the northeastern Pacific, they are commonly called "hurricanes." In the northwest Pacific, the most active tropical cyclone basin in the world, they are “typhoons,” while in the Indian Ocean and South Pacific they are simply “tropical cyclones” or “cyclones.” “Tornadoes”—much smaller and more localized than tropical cyclones, but capable of generating even higher wind speeds—are sometimes colloquially called “cyclones,” although they are completely different storms.

Particularly severe thunderstorms, which generate most of the world's most powerful tornadoes, form rotating updrafts called mesocyclones. In the United States, about 1,700 mesocyclones occur annually, with approximately 50 percent of them becoming tornadoes.

The birth of a huge tornado

Cyclones are among the most dangerous and destructive natural disasters that can occur. They have been responsible for 1.9 million deaths worldwide over the past two centuries. According to some estimates, up to 10,000 people die from these storms each year. Cyclones usually cause the greatest damage to coastal areas.

The consequences of Cyclone Idai - the deadliest tropical cyclone among the cyclones in the southwestern Indian Ocean that existed from March 4 to March 21, 2021. Wind gusts reached speeds of 280 km/h. The cyclone affected the states of Mozambique, Madagascar, Zimbabwe and Malawi, causing severe flooding in the affected areas, leading to numerous casualties. At least 1,297 people were killed, hundreds of thousands were left in need of assistance, and economic losses in these regions totaled more than $2 billion.

Consequences of tropical cyclone Kenneth in Mozambique. The cyclone hit northern Mozambique on April 25, 2021, with heavy rainfall and winds of up to 220 km/h. As a result of the disaster, more than 40 people died. In the Comoros Islands, the cyclone destroyed almost 80% of farms and more than 60% of crops, as well as over 3,800 houses. Previously, Mozambique was seriously affected by tropical cyclone Idai .

2. Extratropical or mid-latitude cyclones . They develop along frontal boundaries in mid-latitudes. These cyclones, which, unlike their tropical counterparts, develop where sharp temperature gradients exist between adjacent air masses, can be much larger than hurricanes, although their winds tend to be weaker. They reach several thousand kilometers in diameter.

3. Polar cyclones, also known as “Arctic hurricanes,” sometimes form over the Arctic and Antarctic seas, caused by the influence of cold air moving over slightly warmer ocean waters. In the Northern Hemisphere, meteorologists sometimes call polar cyclones “Arctic hurricanes” because their energy source is heat transfer from water to air and latent heat released by cloud condensation, and because their spiral cloud bands are somewhat similar to tropical cyclones. Polar cyclones often form quickly, sometimes in less than 24 hours, and are difficult to predict in advance.

An anticyclone is an area of ​​high pressure where air masses descend towards the ground. This usually indicates good weather. Winds in an anticyclone blow clockwise in the northern hemisphere and counterclockwise in the southern hemisphere. Air masses in the center of the anticyclone move downwards, being replaced by a downward flow of air from high altitudes. As it moves down, the air compresses and heats up, which reduces its humidity and leads to a decrease in the number of clouds inside the anticyclone, dry and cloudless weather.

As you know, winds blow from a high pressure system to a low pressure system. In the case of an anticyclone, the wind blows and diverges from the center of the high pressure system. However, it does not flow straight out. Due to the Earth's rotation, air tends to move in a spiral. In the Northern Hemisphere, air currents in areas of high pressure move clockwise, and in the Southern Hemisphere, they move counterclockwise. This pattern ensures that winds to the east of an anticyclone in the Northern Hemisphere will bring cold air from the north, while winds to the west will bring warm air from the south. In the Southern Hemisphere this picture is reversed.

An anticyclone brings stable weather conditions corresponding to the time of year. In summer the weather is windless and hot, in winter it is frosty. It is characterized by few or no clouds.

Anticyclones form in certain areas. For example, they are most often found over large bodies of ice: in Antarctica, Greenland and the Arctic. They also sometimes appear in the tropics.

Anticyclones also carry danger and unpleasant consequences. They can contribute to fires and prolonged drought. With a long absence of wind in large cities, harmful substances and gases accumulate, which is especially important for people with respiratory diseases.

Smog in China. In some cities, it is almost impossible to go outside without a mask. The smog is even visible from space. Scientists have calculated that walking the streets without a mask is equivalent to smoking a pack of cigarettes.

Igor Kibalchich (Kharkov) Published: 10/20/2013

1. AIR TEMPERATURE 1.1 Absolute maximum air temperatures by continent

1.2 Absolute minimum air temperatures by continent

1.3 Other temperature records

• The lowest atmospheric temperature (-143 °C) was recorded at an altitude of 80 – 96 km during a night observation of clouds over Kronogard, Sweden, from July 27 to August 7, 1963[15];

• The lowest average annual temperature was recorded in 1958 in Antarctica, near the South Pole (-57.8 °C) [16];

• The highest average annual air temperature (for the period: October 1960 - November 1966) is +34.4 °C in Dallol, Ethiopia [17];

• The lowest average monthly air temperature (-75.3 °C) was recorded at Vostok station, Antarctica in August 1987 [18];

• The largest average annual temperature amplitude is observed in Verkhoyansk, Russia and is 61.9 °C, the absolute amplitude in this place is 107.1 °C [19];

• The most equable climate is observed in the town of Garapan on the island of Saipan (Mariana Islands), Pacific Ocean. For 9 years from 1927 to 1935. the lowest temperature here was +19.6 °C on January 30, 1934, and the highest was on September 9, 1931 (+31.4 °C), which gives a difference of only 11.8 °C [20]. According to other data, the record holder for the minimum temperature amplitude is the Fernando de Noronha islands off the coast of Brazil. There from 1911 to 1966. the lowest temperature was recorded on November 17, 1913 (+18.6 °C), and the highest was on March 2, 1965 (+32 °C), which is a temperature difference of only 13.4 °C;

The most dramatic warmings:

• In 2 minutes at 27.2 °C. In Spearfish, South Dakota, on January 22, 1943 at 7:30 am the temperature was -20 °C, and just 2 minutes later the temperature rose to +7.2 °C! Such a sharp warming was caused by a sudden warm wind - Chinook [21]; • In 12 hours at 46.1 °C. In the town of Granville, North Dakota (USA) on February 21, 1918, during the day the air temperature rose from -36.1 °C to +10 °C [22];

The most intense cold snaps:

• In 27 minutes at 32.2 °C. In Spearfish, South Dakota, on January 22, 1943, at 9 a.m., the air temperature was +12.2 °C, and at 9:27 it dropped to -20.0 °C [23]; • During the day at 55.6 °C. In the town of Browning, Montana (USA), during January 23-24, 1916, the temperature dropped from +6.7 °C to -48.9 °C [24];

• In Marble Bar, Western Australia, temperatures exceeded 100 °F (+37.8 °C) for 160 days from October 31, 1923 to April 7, 1924 [25];

• The highest dew point (+35 °C) was recorded at 15:00 on July 8, 2003 in the town of Dhahran, Saudi Arabia. The air temperature at this time was +42.2 °C. With a wind of 1 m/s, the effective temperature reached +115 °C![28]

1.4 Water temperature

• On August 8, 1920, the USS Titat recorded a temperature of 100 °F (+37.8 °C) in the Red Sea. The water temperature in the Persian Gulf in July-August usually stays around +31 °C, and on August 5, 1924 it reached a value of +35.6 °C (according to measurements from the Frankenfels ship)[26];

• The hottest river is a tributary of the Amu Darya, Tairsu. Once on this river the temperature of the surface layer of water was recorded at +45.2 °C [27]. On the Tiligul River in the Odessa region, which flows into the Tiligulsky estuary, a temperature of 39.4°C was recorded near the village of Novo-Ukrainka [27]. And the Caspian Sea can be considered the hottest lake. On Biryucha Spit the water temperature was recorded at +37.2 °C.

2. PRECIPITATION 2.1 Highest average annual precipitation by continent [29]

2.2 Lowest average annual precipitation by continent [30]

2.3 Maximum precipitation for different periods of time [33]

• On Mount Waialeale on the Hawaiian Islands, there are on average 330 - 360 rainy days a year [34];

• In Arica (Chile) for 14 years - from October 1903 to January 1918, not a single rain was recorded [33];

• The driest uninhabited place on Earth is located in Antarctica - the Dry Valleys. As calculations show, in this place there has been no precipitation at all over the past 2 million years [35]

2.4 Hail

• Large hail fell in Coffeyville, Kansas, USA on September 3, 1970. The diameter of the hailstones reached 14 cm and weighed 750 g. By calculation, it was established that the hailstones crashed into the ground at a speed of about 47 m/s [37];

• Officially, the heaviest hailstone in the world fell in Gopalganj, Bangladesh on April 14, 1986. Its mass was 1.02 kg [38];

• On April 30, 1888, the deadliest hailstorm in human history occurred in the Indian regions of Moradabad and Beheri. Then 246 people died [38];

• In Europe, the heaviest hailstone is considered to be the one that fell during a thunderstorm in Strasbourg, France on August 11, 1958, weighing 971 grams [38];

• A hailstone with a maximum diameter of 20 cm was discovered in Vivian, South Dakota, USA on July 23, 2010 [96];

• There is information that on May 30, 1879, in Kansas, USA, during the passage of a tornado, hailstones up to 38 cm in diameter were observed. As they fell to the ground, holes were formed measuring 43 x 51 cm [39];

• According to eyewitnesses, in April 1981, hailstones weighing 7 kg were observed in Guangdong Province (China). As a result of this hailstorm, 5 people. about 10,500 buildings were killed and destroyed [40];

• On May 11, 1894, in the town of Bovina, Mississippi, USA, a hailstone was discovered, inside of which there was... a turtle measuring 15 x 20 cm [41];

• In the city of Sheki, Azerbaijan, the largest hail was observed in 1850: individual hailstones weighed about 10 kg. This event was recorded in the journal of the Ministry of Internal Affairs, published in Tbilisi [42];

• In western Kenya, in the Kericho region (where extensive tea plantations are located), there are an average of 132 hail days per year [43];

• In 1965, hail fell in the Kislovodsk region, covering the surface of the earth in some places with a layer of 75 centimeters [44];

• On July 6, 1958, hailstones weighing up to 2 kilograms 200 grams fell in the village of Achikulak, Stavropol Territory. Houses and trees were damaged by the hail, and 90 lambs were killed in the field [44];

• On August 9, 1843, a hailstorm of incredible force and size hit eastern England (from Oxford to Norfolk). Ice blocks up to 25 cm in diameter were recorded, and the layer of hail on the ground in some places reached 1.5 meters [45];

• In 1961, a hailstone weighing 3 kg killed an elephant in northern India [57];

• In October 1985, in the state of Sergipe (Brazil), hailstones killed 20 people and left more than 4,000 homeless. In some places, the thickness of the hail layer exceeded 1.5 meters [57].

2.5 Snow

• On the slopes of Mount Rainier in Washington state, a total of 16.6 m of snow falls on average per year [46]. And in one year from February 19, 1971 to February 18, 1972, 31.11 m of snow fell in the Paradise region (altitude 1646 m above sea level), which is an absolute record for the height of snow cover [47];

• A record snow depth of 11.46 m was recorded in March 1911 in Tamarac, pcs. California, USA [47];

• On February 14, 1927, on Mount Ibuki in Japan (Honshu Island), a snow depth of 11.8 meters was measured! [47];

• In just 19 hours on April 5-6, 1959, 1.7 m of snow fell at the Bessans station in the French Alps [50];

• The heaviest one-day snowfall was recorded in Silver Lake, PC. Colorado, April 14-15, 1921, when 1.93 m of snow fell in one day [48];

• Over 2 days (December 29-30), 1955, 3.1 meters of snow fell in the area of ​​Mile Camp 47 (Alaska) [48];

• The largest snowflake was recorded during a snowfall in the town of Fort Keogh. Montana (USA) January 28, 1887. Its diameter was 38 cm, and its thickness reached 20 cm [49];

3. THUNDERSTORMS Top 5 most thunderstorm places on Earth[52]

• The small village of Kifuka in DR Congo (Africa) is the place with the maximum thunderstorm activity in the entire World. Here, every year there are an average of 158 cloud-to-ground lightning strikes per 1 km2 of territory [53];

• On average, about 2000 thunderstorms thunder on Earth every second and about 100 lightning flashes every second; per day this figure is about 8.6 million flashes, and per year it reaches 3.14 x 109 lightnings [54];

• The lightning recorded by instruments on July 31, 1947 at the University of Pittsburgh, USA is considered the most powerful. The current reached 345,000 A [55];

• The longest lightning strike occurred on October 13, 2001, between Dallas and Fort Worth (Texas). Its length was 193 km (120 mi) [56];

• According to unofficial data, during satellite observations of a strong thunderstorm in the area of ​​the Japanese Islands, the instruments recorded a lightning flash with a power of 1013 W. Such super-powerful discharges are called “superlightning” [57];

• The deadliest strike of all time was a lightning strike on June 26, 1807 in the town of Kirchberg, Luxembourg. On that day, due to a lightning strike, a powerful explosion occurred in a small gunpowder factory, resulting in the death of 300 people [58];

4. WIND 4.1 Tropical cyclones

• The greatest distance – 13,280 km – was covered during the existence of Typhoon “John” in 1994 in the Pacific Ocean [59]. This typhoon also holds the world record for duration of existence - 31 days (from August 10 to September 10) [60];

• The highest horizontal pressure gradient recorded in tropical cyclone Tracy (near Darwin, Australia) on December 24, 1974 was 5.5 hPa/1 km. Also, a gradient of 5 hPa/1 km was observed in Hurricane Inez in the North Atlantic on September 28, 1966 [61];

• Typhoon “Tip” is considered the largest in the northwest Pacific Ocean. On October 12, 1979, a storm wind with a speed of more than 17 m/s was observed within a radius of 1110 km from the center [62];

• The smallest tropical cyclone is considered to be Tropical Storm Marco on October 7, 2008 in the Gulf of Mexico. The zone of storm winds (more than 17 m/s) extended only 16 km from the center [63]. Thus, it is 69 times smaller than Typhoon Type!

• The highest surge wave was observed during the passage of cyclone “Mahina” off the coast of Australia (Queensland) in March 1899. Its height was 13 meters [64];

• The largest “eye of the storm”—90 km in diameter—was observed near tropical cyclone “Kerry” (Coral Sea, February 21, 1979), and the smallest—6.7 km—was recorded near cyclone “Tracy” on December 24, 1974 [65] ;

• The fastest intensification was observed for Typhoon Forest in September 1983 in the northwestern Pacific Ocean. Then, within 24 hours, the pressure in the center of the typhoon dropped by 100 hPa from 976 to 876 hPa, i.e. at a rate of 4.2 hPa/hour [66];

• The highest surface wind speeds were observed in Cyclone Olivia on April 10, 1996 on Barrow Island, Australia. Then, for 3 seconds, the wind blew at a speed of 113.2 m/s (407 km/h) [65];

• According to unofficial data, the sustained maximum wind speed for 1 minute in super typhoon Nancy on September 12, 1961 was 345 km/h (96 m/s) [72];

• The deadliest was tropical cyclone Bhola, which hit Bangladesh on November 12, 1970. According to various estimates, it claimed the lives of 300 to 500 thousand people [67];

• The warmest “eye of the storm” was observed during Typhoon Nora (October 1973) in the western Pacific Ocean. The air temperature at 700 hPa (altitude about 3 km) reached 30 °C [68];

• The most costly was Hurricane Katrina, which struck the United States in August 2005 as a Category 3 hurricane. The damage from it amounted to 108 billion dollars [69];

• Typhoon Nancy (west Pacific) for 5.5 days from September 9 to 14, 1961 was continuously at the stage of maximum category 5 in accordance with the Saffir-Simpson scale [70];

• On December 26, 2001, Tropical Storm Vamei (South China Sea) formed at just 1.4°N latitude. from the equator [71].

List of the most intense tropical cyclones in various regions of the Earth [95]

4.2 Smerchi (Tornado)

• The maximum officially recorded wind speed of the tornado (about 135 m/s) was remotely measured using a rover Doppler radar on May 3, 1999, near Oklahoma City at an altitude of 32 meters above the ground. This value is the world record for surface wind speed [73];

• The tallest waterspout of which there is reliable information was observed on May 16, 1898 at Eden, PC. New South Wales, Australia. Using a theodolite, its height was determined to be 1528 m [74];

• The widest tornado in the world was an EF5 tornado that occurred near El Reno, Oklahoma (USA) on May 31, 2013. Its width reached 4180 meters [73];

• The largest number of tornadoes per month in the USA – 758 – was recorded in April 2011 [77];

• The largest number of tornadoes per year in the USA (1819) was recorded in 2004 [75];

• The most deadly was the tornado that hit the cities of Saturia and Manikgank Sadar, Bangladesh on April 26, 1989. It took the lives of 1,300 people and injured more than 12,000 [33];

• A record number of tornadoes per day - 148 - swept through the southern and midwestern states of the United States on April 3-4, 1974 [76];

• The most costly tornado was the one that hit Joplin, Missouri on May 22, 2011. The total damage is estimated at $2.8 billion [78];

• The highest altitude tornado was recorded on July 7, 2004 in a national park in California (USA). The height of the area where it touched the surface is 3658 m [79];

• The highest speed (117 km/h) was recorded in the Tri-State Tornado on March 18, 1925 [80];

4.3 Other wind records

• The strongest gust of wind on record (without the influence of a tornado or tropical cyclone) occurred on April 12, 1934 at Mount Washington (elevation 1917 meters) in New Hampshire. On that day, instruments recorded a wind speed of 103 m/s [81];

• The windiest place in the world is considered to be Port Martin (Antarctica), where the average annual wind speed is 17 m/s [30]. The highest average annual wind speed in this place was recorded in 1995 and amounted to 22.4 m/s [82]. The highest average monthly wind speed was also recorded here - 29.1 m/s (in March 1951) and average daily wind speed - 48.3 m/s (March 21 - 22, 1951) [51].

5. OTHER WEATHER RECORDS 5.1 Atmospheric pressure

• The highest atmospheric pressure at the earth's surface, normalized to sea level, was recorded on December 19, 2001 in Tosontsengel (Mongolia) and amounted to 1084.8 hPa [85]. The height of this point is 1725 m above sea level. On the plain, the highest pressure was recorded in Agata (Russia) on December 31, 1968 - 1083.3 hPa [86];

• The lowest pressure on Earth was recorded in Typhoon “Tip” in the northwest Pacific Ocean on October 12, 1979 - 870 hPa[87]. In an extratropical cyclone, the lowest pressure (914 hPa) was recorded in the storm “Braer” in the north Atlantic on January 10, 1993 [88];

• The sharpest drop in pressure was observed during the passage of an EF4 tornado near Manchester, South Dakota (USA) on June 24, 2003. Using a special setup, a pressure jump of 100 hPa was measured for about 40 seconds (from 950 to 850 hPa) [89]. The value of 850 hPa can be considered the lowest pressure on the Earth's surface during meteorological observations.

5.2 Sunshine

• The sunniest place is considered to be the town of Yuma, Arizona (USA), where the average annual sunshine is 4019 hours out of 4456 possible [90];

• In St. Petersburg, pcs. Florida, USA, from February 9, 1967 to March 17, 1969 there were 768 completely sunny days in a row [30]

5.3 Ice

• A severe ice storm swept through the southeastern regions of Canada and the northeastern United States on January 4–10, 1998. Then 44 people died, almost 1000 towers of high-voltage power lines were toppled. The thickness of ice deposits in some places reached 12 cm! The total damage is estimated at 5-7 billion dollars [93][94].

5.4 Rainbow

• In the city of Sheffield (UK), the most persistent rainbow was observed: on March 14, 1994, a rainbow was visible for 6 hours: from 09:00 in the morning to 15:00 in the afternoon [92].

5.5 Fog

• The region of the Grand Banks of Newfoundland in the North Atlantic is considered the foggiest place in the World. Another record foggy place is Argentia (Newfoundland, Canada) - 206 days a year with fog [84].

5.6 Dampness

• The Prince Edward Islands in the southern Indian Ocean are the wettest and cloudiest place on earth. The average annual sunshine here is only 800–1300 hours, and it rains about 320 days a year [91].

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How does atmospheric pressure change with altitude?

Atmospheric pressure is directly related to altitude. The higher, the lower the pressure and vice versa. If you rise 12 m above sea level, the mercury column in the barometer will decrease by 1 mm.

Near the Earth's surface, pressure decreases with height at a rate of about 3.5 millibars for every 30 meters. However, in the case of cold air, the decrease in pressure can be much faster because its density is greater than that of warmer air.

At sea level, the atmospheric pressure is about 1000 mb (100 kPa). At the summit of Everest (8848 meters) the pressure drops to about 300 mb (30 kPa).

The pressure at an altitude of 270,000 meters is 10-6 mb, which is comparable to the pressure in the best vacuum ever artificially created by man. At altitudes between 1,500 and 3,000 meters the pressure is so low that it can cause altitude sickness and serious physiological problems if careful acclimatization is not undertaken.

Pressure is most often displayed in hectopascals (1 hPa = 102 Pa) rather than in millimeters of mercury: 1 mmHg. Art. = 133.3 Pa = 1.333 hPa. The relationship between height and pressure is easy to obtain using a simple formula:

∆h /∆P = 12 m/mm Hg. Art. or ∆h/∆P = 9 m/hPa,

where ∆h is the change in height,

∆P - change in pressure.

Thus, with an increase of 9 meters, the pressure level decreases by 1 hPa (100 Pa). This indicator is called the pressure level. Standard atmospheric pressure is 1013 hPa (can be rounded to 1000).

How to calculate the change in pressure at a different altitude using this data? For example, when rising 90 m, the pressure will decrease by 10 hPa. In this case, it turns out that when ascending 900 m, the pressure will drop to 0.

But, since air density also changes with altitude, when it comes to greater distances (starting from 1.5-2 km), all calculations must be carried out taking this parameter into account.

Height versus pressure graph

A graph of changes in atmospheric pressure with altitude clearly displays all of the above. It looks like a curved line rather than a straight line. Due to the fact that the density of the atmosphere is not the same, with increasing altitude the pressure begins to decrease more and more slowly. However, it will never reach zero, because there is a certain amount of particles of matter everywhere - there is no absolute vacuum in the Universe.

Sea pressure

Three quarters of the earth's surface is occupied by water, which forms the Earth's hydrosphere. To determine the physical characteristics of water at great depths, you need to use special methods, and here's why. As it dives to great depths, the layer of water puts more and more pressure on the body being submerged. With a dive of 10 meters, the pressure increases by 100,000 Pa (almost the value of normal atmospheric pressure). This means that when diving to a depth of 1 km, the water pressure will be 100 times greater than atmospheric pressure. The average depth of the World Ocean is 3704 m. The greatest depth is 11034 m in the Mariana Trench, which is located in the Pacific Ocean. At such depths there are enormous pressures.

Mariana Trench on the map

Water is poorly compressible, so its density increases only slightly as it sinks. This means that depth has a greater influence on pressure calculations, i.e. height of the liquid column.

It is interesting that there is life at such depths. Luminous and unusually shaped fish inhabit the seabed. And the sperm whale, the record holder among animals for diving, reaches a depth of 3 km.

Red-lipped pipistrelle[1] Toothed whale sperm whale

A person can dive to great depths, but only experienced divers - pearl divers - can reach a depth of about 85 m. At great depths, water pressure can crush a person's chest. Using diving suits, a person can descend to a depth of 300 m. Divers lay an underwater cable or pipeline along the bottom, build bridges, hydroelectric power stations and locks - a very necessary profession for real men.

But a diver's suit slows down a person's movement. It is connected to the surface of the ship by a cable and a hose through which air flows. This also interferes with movement underwater.

Therefore, the sea explorer Frenchman Cousteau invents scuba gear - new equipment for divers. Scuba divers take with them a supply of air mixture in cylinders. Using the device, it is possible to reach depths of 90 m underwater.

Diver Scuba Diver

According to historians, the first diver was Alexander the Great, who in the 4th century BC descended into the sea in a diving bell. Only in the 20th century did humanity begin to explore the great depths of the World Ocean. Bathyspheres and bathyscaphes are used for this. Bathyspheres are lowered from the ship on a strong cable to a depth of more than 900 m. Bathyscaphes have their own engine and move near the very bottom. From them, observers explore the underwater world. The strong spherical walls of underwater vehicles withstand gigantic pressures.

Bathyscaphe

One of the first submarines was built according to the ideas of J. Verne (the novel “80,000 Leagues[2] Under the Sea”) in 1899. Modern submarines now ply the ocean underwater.

Submarine

Atmospheric pressure in the mountains

In the mountains, the atmospheric pressure will somehow be lower than at the edge of the sea. How a person will feel depends on the altitude and some additional conditions. For example, with normal humidity, climbing 3000 m can cause weakness and decreased performance. This occurs due to lack of oxygen.

In a humid climate, such sensations arise already at an altitude of 1000 m. The fact is that water molecules displace oxygen molecules - there is less oxygen in humid air. And in a dry climate you can climb 5000 m with almost no problems.

The temperature and pressure of the earth's atmosphere change with altitude. Temperatures, indicated by the yellow line, fall with altitude in some zones but rise in others. The pressure, indicated by the black line on the right, decreases greatly with altitude. Encyclopædia Britannica, Inc.

The influence of different altitudes on humans:

- 5 km - there is a lack of oxygen;

— 6 km is the highest altitude at which permanent human settlements exist;

— 8.9 km — the height of Everest. Water at this altitude boils at a temperature of + 68 ℃. Experienced, trained climbers may not be able to stay at this altitude for long;

- 13.5 km - you can only be safe here with a supply of pure oxygen. This is the maximum permissible height at which you can be without special equipment;

— 20 km is a height unacceptable for humans. It is safe only if you are in a hermetically sealed cabin.

A climber stands on the top of Mount Everest, Nepal. Mount Everest is so high that the amount of oxygen there is too low for breathing. Many climbers need oxygen tanks to reach the summit safely.

Atmospheric pressure today:

Journey to the Center of the Earth

The Earth's equatorial radius is 21 kilometers greater than its polar radius. Therefore, the shape of our planet is an oblate ball from the poles. This shape is called an ellipsoid. The average radius of the Earth is usually considered: 6370 km. It was first calculated by the Greek Eratosthenes in the third century BC and the Arab Biruni in the second century BC.

The earth is divided into three main zones:

• core (two parts);
• mantle;
• bark

Structure of the Earth

The thickness of the earth's crust varies from 5 km in the ocean region to several tens of kilometers in mountainous regions. The age of the Earth is approximately 4.5 billion years. Many, many years ago, the earth’s interior was in a molten state, so light elements from the depths floated to the upper layers and formed the crust, and heavy elements, remaining at depth, formed the core. Below the crust to a depth of 2800-2900 km is the mantle. The density of the mantle increases with depth from 3300 kg/m3 to 5000 kg/m3.

The core, consisting of molten iron with admixtures of other dense substances, is divided into external and internal. The outer core reaches a depth of 5000 km and has a density from 10600 kg/m3 to 11500 kg/m3. In the inner core, the density continues to increase towards the center and at a depth of 6370 km (the average radius of the Earth) reaches a maximum value of 12500 kg/m3. From the given figures it is clear that the density does not change systematically, but in discontinuities at the boundaries of the crust - mantle and mantle - core, which was the reason for the identification of three zones of the planet’s structure.

Layers of the lithosphere

The solid rocky (Greek “lithos” - stone) shell of the earth’s crust and upper part of the mantle is called the lithosphere (studied in more detail in geography).

At such depths and densities, it is not difficult to imagine enormous pressure values ​​inside the planet. Using modern instruments, it is calculated that the pressure at a depth of 50 km is 400 times greater than atmospheric pressure. A person can endure pressure three times greater than normal atmospheric pressure. This pressure already exists at a depth of 9 km. Therefore, without special camera devices, a person does not descend deep into the Earth.

At the depths of the Earth

The pressure at the center of the Earth is 353 GPa. This is 350 thousand times more than normal atmospheric pressure.

As you approach the center of the Earth, not only density and pressure increase, but also temperature. At a depth of 10 km, it is about 180o C, at the conventional crust-mantle boundary (about 33 km) - 420o C. The temperature in the center of the core is more than 6100o C.

So:

• The atmosphere exerts pressure on the Earth and bodies located on and near its surface. With altitude the pressure decreases;
• hydrosphere is the watery shell of the Earth. With descent to the bottom of the World Ocean, pressure increases to gigantic values ​​(several tens of millions of Pascals);
• lithosphere - the solid shell of the Earth. At great depths, the pressure is hundreds of times greater than atmospheric pressure.