Cyclone. What is a cyclone? Tropical cyclone in the Southern Hemisphere. Cyclones and anticyclones - characteristics and names What is a cyclone definition

More recently, before the invention of satellites, meteorologists could not even imagine that about 150 cyclones and about 60 anticyclones occur annually in the earth's atmosphere.


Now scientists know not only their number, but also the process of formation, as well as the impact on the Earth. What are these natural phenomena? How do they arise and what role do they play in the Earth's climate?

What is a cyclone?

In the troposphere (lower atmospheric layer), atmospheric vortices constantly appear and disappear. Many of them are quite small, but some are huge and reach several thousand kilometers across.

If such a vortex moves counterclockwise in the northern hemisphere or clockwise in the southern, and inside there is an area of ​​low pressure, then it is called a cyclone. It has a colossal supply of energy and leads to negative weather events such as thunderstorms, strong winds, and squalls.

Depending on the place of formation, cyclones are tropical and extratropical. The former occur in tropical latitudes and are small in size (several hundred kilometers in diameter). In their center there is usually an area with a diameter of 20–25 km with sunny weather, and storms and winds rage along the edges.


Extratropical cyclones formed in polar and temperate latitudes reach gigantic proportions and simultaneously cover large areas of the earth's surface. In different areas they are called differently: in America -, in Asia - typhoon, and in Australia - willy-willy. Each powerful cyclone gets its own name, such as Katrina, Sandy, Nancy.

How does a cyclone form?

The reason for the occurrence of cyclones lies in the rotation of the globe and is associated with the Coriolis force, according to which, when moving counterclockwise, the vortices deviate to the left, and clockwise go to the right. Cyclones form when warm equatorial air masses meet dry arctic currents. When they collide, a barrier arises between them - an atmospheric front.

In an attempt to overcome this boundary, cold flows push aside part of the warm layers, and those, in turn, collide with the cold masses following them and begin to rotate along an ellipsoidal trajectory. Gradually, they capture the enclosing air layers, draw them into their movement and move along the Earth's surface at a speed of up to 50 kilometers per hour.

What is an anticyclone?

Anticyclones, as the name implies, are the exact opposite of cyclones and bring good weather to certain areas.


In their inner part there is an area of ​​high pressure, and the speed of movement varies from 30 to 40 kilometers per hour, depending on the hemisphere. Quite often, anticyclones hover in a stationary state, keeping a small cloud cover, calmness and lack of precipitation for a long time in a particular region.

In summer, anticyclones lead to heat, in winter, on the contrary, to severe frosts. They arise in subpolar or subtropical latitudes, and when formed over a thick ice cover (for example, in Antarctica) they become more pronounced.

Anticyclones are characterized by sharp temperature changes throughout the day, which explains the absence of precipitation, which, as a rule, affects the temperature and makes the difference in degrees not so noticeable. Sometimes, during their movement, fogs or stratus clouds appear above the earth's surface.

How do anticyclones develop?

Anticyclones have a more complex structure than cyclones. In the northern hemisphere they move clockwise, in the southern - against. The formation of anticyclones leads to the invasion of cold air currents into warmer ones.


As a result, pressure rises in the collision area and a so-called high-altitude ridge is formed, under which the center of the vortex begins to form. As they grow, anticyclones reach sizes up to several thousand kilometers in diameter and move from west to east, deviating to lower latitudes.

Atmospheric phenomena have been an object of study for centuries because of their significance and influence on all spheres of life. Cyclones and anticyclones are no exception. The concept of these weather phenomena is given at school by geography. Cyclones and anticyclones, after such a brief study, remain a mystery to many. and fronts are key concepts that will help capture the essence of these weather events.

air masses

It often happens that for many thousands of kilometers in a horizontal direction, the air has very similar properties. This mass is called air mass.

Air masses are divided into cold, warm and local:

A cold mass is called if its temperature is lower than the temperature of the surface over which it is located;

Warm - this is such an air mass, the temperature of which is higher than the temperature of the surface that is under it;

The local air mass does not differ in temperature from the surface below it.

Air masses form over different parts of the Earth, which leads to peculiarities in their properties. If the mass is formed over the Arctic, then, accordingly, it will be called Arctic. Of course, such air is very cold, it can bring thick fogs or light haze. Polar air considers temperate latitudes to be its deposit. Its properties may vary depending on what time of the year it is. In winter, the polar masses are not much different from the Arctic ones, but in summer such air can bring very poor visibility.

Tropical masses that came from the tropics and subtropics have a high temperature and increased dust content. They are responsible for the haze that covers objects when viewed from a distance. Tropical masses formed on the continental part of the tropical belt lead to dust whirlwinds, storms and tornadoes. Equatorial air is very similar to tropical air, but all these properties are more pronounced.

Fronts

If two air masses with different temperatures meet, a new weather phenomenon is formed - a front, or interface.

According to the nature of the movement, the fronts are divided into stationary and mobile.

Each existing front divides the air masses among themselves. For example, the main polar front is an imaginary mediator between polar and tropical air, the main arctic front is between arctic and polar air, and so on.

When a warm air mass moves over a cold air mass, a warm front occurs. For travelers, the entrance to such a front may herald either heavy rain or snow, which will significantly reduce visibility. When cold air is wedged under warm air, a cold front is formed. Ships entering the cold front suffer from squalls, downpours and thunderstorms.

It happens that air masses do not collide, but catch up with one another. In such cases, an occlusion front is formed. If the role of the catching-up is performed by the cold mass, then this phenomenon is called the front of cold occlusion, if vice versa, then the front of warm occlusion. These fronts bring torrential weather with strong gusts of wind.

Cyclones

To understand what an anticyclone is, you need to understand, This is an area in the atmosphere with a minimum indicator in the center. It is generated by two having different temperatures. Very favorable conditions for their formation are created in the fronts. In a cyclone, air moves from its edges, where the pressure is higher, to the center. In the center, the air seems to be thrown upwards, which makes it possible to form ascending flows.

By the way the air moves in a cyclone, it is easy to determine in which hemisphere it was formed. If its direction coincides with the movement of the hour hand, then this is definitely the Southern Hemisphere, if it is against it, this is

Cyclones provoke such weather phenomena as the accumulation of cloud masses, heavy precipitation, wind and temperature changes.

tropical cyclone

From cyclones formed in temperate latitudes, cyclones are separated, which owe their origin to the tropics. They have many names. These are hurricanes (West Indies), and typhoons (east of Asia), and simply cyclones (Indian Ocean), and arcana (south of the Indian Ocean). The dimensions of such vortices range from 100 to 300 miles, and the diameter of the center is from 20 to 30 miles.

The wind here accelerates to 100 km / h, and this is typical for the entire area of ​​​​the vortex, which radically distinguishes them from cyclones formed in temperate latitudes.

A sure sign of the approach of such a cyclone is ripples on the water. Moreover, it goes in the opposite direction to the blowing wind or the wind that blew shortly before.

Anticyclone

The area of ​​high pressure in the atmosphere with a maximum in the center is the anticyclone. The pressure at its edges is lower, which allows air to rush from the center to the periphery. The air located in the center constantly descends and diverges towards the edges of the anticyclone. This is how downward flows are formed.

An anticyclone is the opposite of a cyclone also because in the Northern Hemisphere it follows the hour hand, in the Southern Hemisphere it goes against it.

After re-reading all the above information, we can say with confidence what an anticyclone is.

An interesting property of anticyclones of temperate latitudes is that they seem to follow cyclones. In this case, the sedentary state fully characterizes the anticyclone. The weather formed by this vortex is slightly cloudy and dry. There is practically no wind.

The second name of this phenomenon is the Siberian maximum. Its life expectancy is about 5 months, namely the end of autumn (November) - the beginning of spring (March). This is not one anticyclone, but several, which very rarely give way to cyclones. The height of the winds reaches 3 km.

Due to the geographical environment (mountains of Asia) cold air cannot disperse, which leads to even more cooling, the temperature near the surface drops to 60 degrees below zero.

Speaking about what an anticyclone is, we can say with confidence that this is an atmospheric vortex of enormous size, bringing clear weather without precipitation.

Cyclones and anticyclones. Similarities and differences

In order to understand better what an anticyclone and a cyclone are, you need to compare them. We have clarified the definitions and main aspects of these phenomena. The question of how cyclones and anticyclones differ remains open. The table will show this difference more clearly.

Thus, we see how cyclones and anticyclones differ. The table shows that these are not just opposites, the nature of their occurrence is completely different.

air masses- these are large air masses of the troposphere and lower stratosphere, which are formed over a certain territory of land or ocean and have relatively uniform properties - temperature, transparency. They move as one unit and in the same direction in the atmosphere system.

Air masses occupy an area of ​​thousands of square kilometers, their thickness (thickness) reaches up to 20-25 km. Moving over a surface with different properties, they heat up or cool down, or become drier. Warm or cold air mass is called, which is warmer (colder) than its environment. There are four types of air masses depending on the areas of formation: equatorial, tropical, temperate, arctic (Antarctic) air masses (Fig. 13). They differ primarily in temperature and humidity. All types of air masses, except for equatorial ones, are divided into maritime and continental, depending on the nature of the surface over which they formed.

The equatorial air mass is formed in the belt. It has rather high temperatures and humidity close to the maximum, both over land and over the sea. Continental tropical air mass is formed in the central part of the continents in. It has high temperature, low humidity, high dust content. Marine tropical air mass is formed over the oceans in tropical latitudes, where rather high air temperatures prevail and high humidity is noted.

Continental moderate air mass is formed over the continents in, dominates the Northern Hemisphere. Its properties change with the seasons. In summer, the temperature and humidity are quite high, precipitation is typical. In winter, low and extremely low temperatures and low humidity. Marine temperate air mass forms over oceans with warm currents in temperate latitudes. It is cooler in summer, warmer in winter, and has significant humidity.

The continental Arctic (Antarctic) air mass is formed over the ice of the Arctic and has extremely low temperatures and low humidity, high transparency. Marine Arctic (Antarctic) air mass is formed over periodically freezing seas and oceans, its temperature is slightly higher, humidity is higher.

Air masses are in constant motion; when they meet, transition zones, or fronts, are formed. - the border zone between two having different properties. The width of the atmospheric front reaches tens of kilometers. Atmospheric fronts can be warm or cold, depending on what kind of air is moving into the territory and what is being displaced (Fig. 14). Most often, atmospheric fronts occur in temperate latitudes, where cold air from polar latitudes and warm air from tropical latitudes meet.

The passage of the front is accompanied by changes in . The warm front moves towards the cold air. It is associated with warming, nimbostratus clouds, bringing drizzling precipitation. The cold front moves towards the warm air. It brings abundant short-term heavy rainfall, often with squally and, and cooling.

Cyclones and anticyclones

In the atmosphere, when two air masses meet, large atmospheric vortices arise -. They are flat air vortices covering thousands of square kilometers at a height of only 15-20 km.

Cyclone- an atmospheric vortex of huge (from hundreds to several thousand kilometers) diameter with reduced air pressure in the center, with a system of winds from the periphery to the center against in the Northern Hemisphere. In the center of the cyclone, ascending air currents are observed (Fig. 15). As a result of ascending air currents, powerful clouds form in the center of cyclones and precipitation falls.

In summer, during the passage of cyclones, the air temperature decreases, and in winter it rises, a thaw begins. The approach of a cyclone causes cloudy weather and a change in wind direction.

Tropical cyclones occur in tropical latitudes from 5 to 25° in both hemispheres. Unlike cyclones of temperate latitudes, they occupy a smaller area. Tropical cyclones occur over the warm sea surface in late summer - early autumn and are accompanied by powerful thunderstorms, heavy rainfall and storm-force winds, which have tremendous destructive power.

In tropical cyclones they are called, in the Atlantic -, off the coast of Australia - willy-willy. Tropical cyclones carry a large amount of energy from tropical to temperate latitudes, which makes them an important component of global atmospheric circulation processes. For their unpredictability, tropical ones are given female names (for example, "Catherine", "Juliet", etc.).

Anticyclone- an atmospheric vortex of huge diameter (from hundreds to several thousand kilometers) with an area of ​​high pressure near the earth's surface, with a system of winds from the center to the periphery clockwise in the Northern Hemisphere. Downdrafts of air are observed in the anticyclone.

Both in winter and in summer, the anticyclone is characterized by a cloudless sky and calmness. During the passage the weather is sunny, hot in summer and very cold in winter. Anticyclones form over the ice sheets of Antarctica, over, over the oceans in tropical latitudes.

The properties of air masses are determined by the areas of their formation. When they move from their places of formation to others, they gradually change their properties (temperature and humidity). Due to cyclones and anticyclones, heat and moisture are exchanged between latitudes. The change of cyclones and anticyclones in temperate latitudes leads to sharp changes in the weather.

Then the air flow rapidly turns into a powerful whirlwind, the wind speed increases significantly and penetrates into the upper layers of the atmosphere. The cyclone captures the adjacent layers of air, dragging them at a speed of up to 50 km / h. On the distant fronts, a greater speed is achieved than in the center. During this period, due to low pressure, there is a sharp change in the weather.

A developed cyclone passes into the fourth stage and acts for four days or more. The cloud vortex closes in the center and then shifts to the periphery. At this stage, the speed decreases, heavy precipitation falls.

The phenomenon of a cyclone is characterized by a lack of air. Cold currents come in to replenish it. They push warm air up. As it cools, the water condenses.

Clouds appear, from which heavy precipitation falls. Here is what a cyclone is and why the weather changes dramatically when it occurs.

Types of cyclones

The duration of the vortex is from several days to weeks. In an area of ​​low pressure, it can last up to a year (for example, the Icelandic or Aleutian cyclone). According to their origin, the types of cyclones differ depending on the place of its occurrence:

• eddies in temperate latitudes
• tropical vortex
• equatorial
• arctic

In the Earth's atmosphere, the movement of masses is constantly formed. Whirlwinds of various sizes are destroyed all the time in it. Warm and cold air currents collide in temperate latitudes and form areas of high and low pressure, which leads to the formation of vortices.

A tropical cyclone poses a great danger. It forms where the surface temperature of the ocean is at least twenty-six degrees. Increased evaporation contributes to an increase in humidity. As a result, vertical air masses rush upward.

With a strong impulse, new volumes of air are captured. They have already warmed up enough and become wet above the surface of the ocean. Rotating at great speed, the air currents turn into hurricanes of destructive force. Of course, not every tropical cyclone brings destruction. When they move to land, they quickly subside.

Movement speed in different stages

1. movement not exceeding 17 m/s is characterized as a disturbance
2. at 17-20 m/s there is some depression
3. when the center reaches 38 m/s, a storm is coming
4. when the forward movement of the cyclone exceeds 39 m/s, a hurricane is observed

In the center of the cyclone, an area of ​​calm weather prevails. Inside, a warmer temperature is formed than in the rest of the air flow, less humidity is observed. The tropical cyclone is the southernmost one, it is smaller and has a higher wind speed.

For convenience, the phenomena of anticyclones and cyclones were first called numbers, letters, etc. Now they have received female and male names. When exchanging information, this does not create confusion and reduces the number of errors in forecasts. Each name contains certain data.

The phenomena of anticyclone and cyclone that form over the ocean differ in their properties from those that have arisen over the mainland. Marine air masses are warm in winter and cold in summer compared to continental air.

Tropical cyclones

Tropical cyclones mainly capture areas of the southeast coast of Asia, the eastern part of the island of Madagascar, the Antilles, the Arabian Sea and the Bay of Bengal. More than seventy powerful cyclones are observed per year.

They are called differently, depending on the place of origin:

• North and Central America - Hurricane
• West coast of Mexico in the Pacific Ocean - cordonaso
• East Asia - typhoon
• Philippines - Baruyo / Baguyo
• Australia - Willy Willy

The properties of temperate, tropical, equatorial and arctic air masses are easily identified by name. Each tropical cyclone has its own name, such as "Sarah", "Flora", "Nancy", etc.

Conclusion

Vertical-horizontal movements of air masses move in space. The atmosphere is an ocean of air, the winds are its course. Their boundless energy carries heat and moisture across all latitudes, from the oceans to the continents and back. Moisture and heat on Earth is redistributed due to the constant movement of air masses.

If it were not for the phenomenon of anticyclones and cyclones, then the temperature at the poles would be lower, and at the equator it would be hotter.

The phenomenon of anticyclone and cyclone is a powerful force that can destroy, deposit and transfer rock particles from one place to another.

At first, mills worked from the wind, where they ground grain. On sailboats, he helped to overcome long distances of the seas and oceans. Later, wind turbines appeared, with the help of which people receive electricity.

A cyclone and an anticyclone is a natural “mechanism” that carries air masses and affects weather changes. More and more delving into the secrets of what cyclones and anticyclones are, perhaps people will learn to use these natural phenomena with maximum benefit and benefit for humanity.

Anticyclone

The Hydrometeorological Center of Russia decided to give names to cyclones, anticyclones and other weather systems with high intensity and increased risk operating on the territory of the Russian Federation.

According to the weather service, every Russian who wishes will be able to participate in the choice of names.

The hydrometeorological center believes that a unified authoritative system for naming weather systems (cyclones, anticyclones) that affect the weather and can cause dangerous weather events can work on the territory of the Russian Federation when it is necessary to issue appropriate storm warnings.

For example, in Germany for the second decade names have been given to cyclones and anticyclones, including cyclones Godard, Edwin, Kirill.

Australian meteorologist Clement Ruggom named the typhoons after MPs who refused to vote for weather research loans.

During World War II, US Air Force and Navy meteorologists monitored typhoons in the Pacific Northwest and named typhoons after their wives or girlfriends. By what principle they will give names to natural phenomena in Russia is not yet known.

Svetlana Suvorina, School of the Investor.

What else?

Have you ever seen huge atmospheric vortices?

The zones of high and low pressure can form large atmospheric vortices, which are called cyclones and anticyclones. These atmospheric vortices are usually formed when powerful air currents collide.

Let's imagine such a picture. A powerful air current passes along the western coast of Africa. At a certain point, the coastline turns sharply to the right, but the flow continues its way in the same direction.

In the open sea, he meets another atmospheric current, which moves across it, along the northern coast of Africa. The Nord Stream begins to sag, experiencing strong pressure from the side. And the southern current, moving along the formed gutter, begins to wrap in a circle and turn into an atmospheric vortex.

A cyclone usually brings bad weather with it, since the atmospheric pressure inside it is lower than outside. He draws in the clouds. In an anticyclone, the opposite is true. The pressure in its center is higher than on the outside.

Cyclones and anticyclones

Therefore, the clouds do not fall into the middle of the anticyclone.

But it would be wrong to think that in the entire region of the cyclone the entire sky is covered with clouds and there are continuous rains. If you look at the cyclone from above, from space, it turns out that the cloudiness inside this giant vortex is distributed in the form of elongated oval bands that tend to the center of the cyclone. These areas of cloudiness are called atmospheric fronts. Usually, after the appearance of one cyclone, others are formed. There can be up to 5 vortices in total.

Cyclones move at an average speed of 30-40 kilometers per hour, and sometimes they accelerate to 100 kilometers per hour. These whirlwinds are so huge that they often reach 1500-2000 kilometers in diameter.

CYCLONE (Greek kyklon - rotating) - an area of ​​​​low atmospheric pressure that occurs in a warm air mass when it collides with a cold one, that is, when an atmospheric front occurs. With an uneven front boundary, dense cold air in some area pushes some of the warm air back. Turning back and opposing the general movement of the warm air mass, this part, with an increase in atmospheric pressure, is forced to deviate to the side and swirl. There is an ellipsoidal rotation of the air, compacted along the periphery, in the inner part with an increased temperature. This vortex covers the entire frontal part of the warm air mass, gradually drawing it all into rotation. The cyclone moves at a speed of 30-50 km / h, in most cases from west to east, according to the rotation of the Earth. In the northern hemisphere, its rotation is counterclockwise, and in the southern hemisphere in its direction. Before the complete destruction of the cyclone, it takes from several days to several weeks. The diameter of the cyclone is usually 1000-2000 km, and the height is from 2 to 20 km.

With the onset of a cyclone, the weather changes dramatically. The wind is picking up as there is low pressure at the center of the cyclone and hence the winds will blow there. A cyclone is necessarily accompanied by the formation of clouds and precipitation. This is due to the fact that in its center the air is warm, and the surrounding cold air tries to suppress it. The ring of cold contracts, forcing warm air up where it cools, water vapor condenses into water droplets, clouds form, and precipitation falls. Cyclones usually occur in a year up to several hundred, and they become the main link in the general circulation of the atmosphere, most often in polar and temperate latitudes. Originating over the ocean, due to the reduced atmospheric pressure in the central part, cyclones contribute to the rise of deep cool waters to the surface, and hence their enrichment with plankton.

Cyclones originating over the North Atlantic have the greatest influence on the climate of Russia. Due to the constant influx of warm waters from the North Atlantic Current, moderate sea air masses are formed here and a low pressure area is maintained - the so-called Iceland Low. On the outskirts of it, cyclones constantly arise.

What is a cyclone and anticyclone?

They are transported from west to east over Europe and penetrate even into Western Siberia. The effect of these cyclones is felt throughout the north of the East European Plain. They fade only on the Taimyr Peninsula. The passage of these cyclones causes cloudy, rainy weather, mitigates the heat in summer and the cold in winter.

The East of Russia is under the influence of the Aleutian Low, which manifests itself only in winter. It causes intense cyclones with heavy snowfalls and winds in Kamchatka, the Kuril Islands.

In the 8th grade geography course, a number of topics are studied on various processes in the atmosphere. They need to be studied and understood, as they reveal the causes and methods of weather formation and change, its prediction, which is of practical value for every person.

What are cyclones and anticyclones

One of the most interesting mechanisms is a kind of "air pumps" - huge atmospheric vortices, the main role of which is the formation of weather over large areas of the earth's surface.

Their height is up to 20 km, and their diameter can reach 4-5 thousand km.

Rice. 1. Giant atmospheric vortex.

In this case, the cyclone is an air vortex that collects and ejects air upwards from its own center. An anticyclone, on the contrary, draws in air from the upper layers of the atmosphere and distributes it near the surface.

This is because the cyclone is an area of ​​low pressure, the air rushes to where the pressure is the lowest, that is, to the center of the cyclone. There are rising air currents.

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An anticyclone is an atmospheric vortex characterized by high pressure. On the contrary, it “accelerates” air masses from its own center, drawing them in from higher layers of the atmosphere. In its center, descending flows are formed, which are distributed spirally from the center over the earth's surface.

Atmospheric vortices are often formed in the areas of atmospheric fronts, the main reason for their formation is the rotation of the Earth.

Rice. 2. Scheme of the structure of a cyclone and an anticyclone.

Similar phenomena are observed in the atmosphere of other planets. An extraterrestrial long-lived cyclone is the Little Dark Spot in the atmosphere of Neptune, and an anticyclone is the Great Red Spot on Jupiter.

Comparison of features of atmospheric vortices

Cyclones and anticyclones have features of difference and similarity. Their similarities are:

• vortex structure;
• an important role in shaping the weather over large regions.

The appearance of an anticyclone is influenced by the formation of cyclones nearby - excess air emitted by a low pressure vortex accumulates and provokes the development of an area of ​​high pressure, anticyclones.

The features of differences in atmospheric vortices are presented in the table of comparative characteristics:

On synoptic maps, letters are used to designate cyclones and anticyclones: H - means an area of ​​low pressure, B - an area of ​​high pressure.

Rice. 3. Synoptic map.

Types of cyclones and anticyclones

There are several types of cyclones, named after the place of formation:

• arctic;
• temperate latitudes;
• southern extratropical;
• tropical.

Most of the cyclones passing through the territory of Russia form over the Atlantic, move from west to east and are classified as arctic or temperate. These are large atmospheric vortices.

Tropical cyclones are the most dangerous - they are characterized by relatively small sizes of only hundreds of kilometers, anomalously low pressure in the center, and, consequently, very high wind speeds reaching storm winds. It is these cyclones that cause the greatest destruction in the coastal countries of Asia and North America. They arise only over the sea and quickly fade when moving to land.

Anticyclones and cyclones have an average lifetime of 3-10 days until the atmospheric pressure equalizes. However, there are also permanent ones that exist for years, for example: the Icelandic and Aleutian cyclones, the Indian and Siberian anticyclones.

What have we learned?

The formation of atmospheric vortices depends on the distribution of air pressure in the atmosphere and the Coriolis forces that arise during the rotation of the Earth. With some similarities, they are much different from each other: they rotate in different directions, provide different weather, and arise in different conditions.

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