Geography cyclone and anticyclone designations. Symbols on domestic facsimile cards. Cyclone born over the tropics

Some time ago, scientists could not even think that about two hundred cyclones and about fifty anticyclones were formed on the surface of the planet, because many of them remained invisible due to the lack of weather stations in the areas where they occur. But now there are satellites that capture the emerging changes. What is a cyclone and anticyclone, and how do they arise?

First, what is a cyclone

The cyclone is a huge atmospheric vortex with low air pressure. In him air masses always shuffle counterclockwise in the north and clockwise in the south.

They say that a cyclone is a phenomenon that is observed on different planets, including the Earth. It comes from the rotation celestial body. This phenomenon has great power and brings with it the strongest winds, precipitation, thunderstorms and other phenomena.

Anticyclone

In nature, there is such a thing as an anticyclone. It is not difficult to guess that this phenomenon is the opposite of a cyclone. It is characterized by the movement of air masses counterclockwise in the southern hemisphere and clockwise in the northern hemisphere.

Anticyclones are able to stabilize the weather. Calm calm weather sets in over the territory after them: in summer it is hot, and in winter it is frosty.

Cyclones and anticyclones

So what is a cyclone and anticyclone? These are two phenomena that occur in the upper atmosphere and carry different weather. The only thing these phenomena have in common is that they arise over certain territories. For example, anticyclones most often occur over ice fields. And the larger the area of ​​ice, the stronger the anticyclone.

For centuries, scientists have tried to determine what a cyclone is, what its significance is and what it affects. The key concepts of this atmospheric phenomenon are air masses and fronts.

air masses

Over many thousands of kilometers, horizontal air masses have the same properties. They are divided into cold, local and warm:

1. Cold ones have a lower temperature than on the surface above which they are located.
2. Warm ones have more than on the surface where they are located.
3. The local mass is air, the temperature of which is no different from the territory that is located under it.

Air masses form over the most different sections Earth, which determines their features and various properties. The area over which air masses form gives them their name.

For example, if they arise over the Arctic, then they are given the name Arctic. Such air is cold, with fogs, haze. Tropical air masses bring heat and lead to the formation of whirlwinds and tornadoes, storms.

Cyclones

An atmospheric cyclone is an area reduced pressure. It occurs due to two air currents with different temperatures. The center of the cyclone has minimal atmospheric indicators: the pressure in its central part is lower, and along the edges it is high. It seems that the air masses are thrown upwards, thereby forming ascending air currents.

In the direction of movement of air masses, scientists can easily determine in which hemisphere it was formed. If its movement coincides with the hour hand, then it originated in the Southern Hemisphere, and if the air moves against it, the cyclone came from the Northern Hemisphere.

In the zone of action of the cyclone, phenomena such as accumulations of cloud masses, sudden changes in temperature, precipitation, thunderstorms, whirlwinds can be observed.

Cyclone born over the tropics

Tropical cyclones are different from those that occur over other areas. Such types of phenomena are the most different names: hurricanes, typhoons, arcana. Usually tropical eddies are large - up to three hundred miles or more. They are able to drive wind at speeds of over 100 km/h.

A distinctive feature of this atmospheric phenomenon from others is that the wind accelerates throughout the territory of the cyclone, and not only in certain zones, as is the case with cyclones that occur in temperate zone. The main sign of the approach of a tropical cyclone is the appearance of ripples on the water. Moreover, she goes to opposite side from the wind.

In the 70s of the last century, tropical cyclone Bhola hit Bangladesh, which was assigned the third category of the existing five. He had a small wind speed, but the accompanying rain caused the Ganges to overflow the banks, which flooded all the islands, washing away all the settlements. More than 500 thousand people died as a result of this disaster.

Cyclone scales

Any cyclone action is rated on the hurricane scale. It indicates the category, wind speed and storm tide:

1. The first category is considered the easiest. With it, a wind of 34-44 m / s is observed. The storm tide does not exceed two meters.
2. Second category. It is characterized by winds of 50-58 m/s and storm surge up to 3 m.
3. Third category. Wind strength can reach 60 meters per second, and storm tide - no more than 4 m.
4. Fourth category. Wind - up to 70 meters per second, storm tide - about 5.5 m.
5. The fifth category is considered the strongest. It includes all cyclones with a wind force of 70 meters per second and with a storm surge of more than 5.5 meters.

One of the most notorious Category 5 tropical hurricanes is Katrina, which has killed nearly 2,000 people. Also, the fifth category received hurricanes: "Wilma", "Rita", "Ivan". During the passage of the latter through the territory of America, more than one hundred and seventeen tornadoes formed.

Stages of cyclone formation

The characteristic of a cyclone is determined during its passage through the territory. At the same time, its stage of formation is specified. There are four in total:

1. First stage. It is characterized by the beginning of the formation of a vortex from air flows. At this stage, deepening occurs: this process usually takes about a week.
2. young cyclone. A tropical cyclone in a young stage may go into different directions or move in the form of small air masses over short distances. A pressure drop occurs in the central part, a dense ring begins to form around the center, with a radius of about 50 km.
3. maturity stage. It is characterized by the cessation of pressure drop. At this stage, the wind speed reaches its maximum and stops increasing. The storm wind radius is placed on the right side of the cyclone. This stage can be observed from several hours to several days.
4. Attenuation. When the cyclone makes landfall, the attenuation stage begins. During this period, the hurricane can go in two directions at once, or it can gradually fade, turning into lighter tropical eddies.

snake rings

Cyclones (from the Greek "serpent ring") are gigantic eddies, whose diameter can reach thousands of kilometers. They usually form in places where air from the equator collides with cold currents going towards it. The boundary formed between them is called the atmospheric front.

During a collision, warm air does not allow cold air to pass through. In these areas, pushing occurs, and the air mass is forced to rise higher. As a result of such collisions between the masses, the pressure rises: part of the warm air is forced to deviate to the side, yielding to the pressure of the cold one. So there is a rotation of air masses.

The resulting vortices begin to capture new air masses, and they begin to move. Moreover, the movement of the cyclone in its central part is less than along the periphery. In those zones where the vortex moves sharply, there are strong jumps in atmospheric pressure. In the very center of the funnel, a lack of air is formed, and in order to somehow make up for it, cold masses enter the central part. They begin to displace warm air upward, where it cools, and the water droplets in it condense and form clouds, from which precipitation then falls.

Vortices can live for several days or several weeks. In some regions, cyclones were recorded, almost a year old. This phenomenon is typical for areas with low pressure.

Types of cyclones

There are the most different types whirlwinds, but not every one of them brings destruction. For example, where cyclones are weak but very windy, the following phenomena can be observed:

• Perturbations. With this phenomenon, the wind speed does not exceed seventeen meters per second.
• Storm. In the center of the cyclone, the speed of movement is up to 35 m/s.
• Depression. In this form, the speed of the cyclone is from seventeen to twenty meters per second.
• Hurricane. With this option, the cyclone speed exceeds 39 m/s.

Scientists about cyclones

Every year, scientists around the world record the strengthening of tropical cyclones. They become stronger, more dangerous, their activity grows. Because of this, they are found not only in tropical latitudes, but also in European countries and at an unusual time for them. Most often this phenomenon is observed in late summer and early autumn. So far, cyclones are not observed in spring.

One of the most powerful whirlwinds that swept over the countries of Europe was Hurricane Lothar in 1999. He was very powerful. Meteorologists could not fix it due to the failure of sensors. This hurricane caused the death of hundreds of people and caused serious damage to the forests.

Record cyclones

In 1969, Hurricane Camila struck. In two weeks, he reached from Africa to America and reached a wind force of 180 km / h. After passing through Cuba, his strength weakened by twenty kilometers, and scientists believed that by the time he reached America, he would weaken even more. But they were wrong. After crossing the Gulf of Mexico, the hurricane again gained strength. "Camila" was assigned the fifth category. More than 300 thousand people were missing, thousands were injured. Here are some more sad records:

1. Cyclone "Bhola" in 1970, which claimed more than 500 thousand lives, became the record for the number of victims. The potential number of victims could reach a million.
2. In second place is Hurricane Nina, which killed more than a hundred thousand people in China in 1975.
3. In 1982 in Central America Hurricane Paul raged, killing thousands of people.
4. In 1991, Cyclone Thelma hit the Philippines, killing several thousand people.
5. The worst was Hurricane Katrina in 2005, which claimed nearly 2,000 lives and caused almost $100 billion in damage.

Hurricane Camila is the only hurricane to make landfall in full force. Wind gusts reached 94 meters per second. Another record holder for wind strength is registered on the island of Guam. The typhoon had a wind force of 105 meters per second.

Among all the recorded eddies, the largest diameter was "Type", spread over more than 2100 kilometers. The smallest typhoon is Marco, which has a wind diameter of only 37 kilometers.

Judging by the lifespan of the cyclone, “John” raged the longest in 1994. It lasted 31 days. He also holds the record for the longest distance traveled (13,000 kilometers).

On domestic synoptic maps of the low pressure zone - cyclones (Low Pressure Systems, Cyclones)- are denoted by the letter H (low). On foreign maps the letter L is used (Low, low pressure).

In the northern hemisphere, due to the Coriolis force, the air masses deviate to the right in the course of their movement and twist around the area of ​​high pressure clockwise, and around the area low pressure- counterclock-wise:

In the southern hemisphere, the opposite is true.

It is cyclones that bring us the main troubles - giant air vortices with warm and cold fronts. At the time of the cyclone temperate latitudes has a size of about 500 nautical miles in diameter.

Let's look at how a typical cyclone of temperate latitudes arises, develops and ceases to exist in the northern hemisphere.

1. As we already know, in the region of 60 ° latitude, warm air masses that came from the subtropics and cold polar air coexist side by side. Imagine that on the boundary of these masses there is an oncoming local movement.

2. The warm wind is directed to the north, the cold wind is directed to the south, from the area of ​​contact of these winds the air is blown in different directions and an area of ​​low pressure is formed.

3. Due to the action of the Coriolis force, the air masses begin to twist around the formed area of ​​low pressure counterclockwise and mix. The fronts of warm and cold air begin to rotate.

4. The front is the boundary zone between the masses of warm and cold air. If a mass of warm air moves over a mass of cold air, it is warm front(Warm Front), if vice versa - cold (Cold Front). On the synoptic map, a warm front is indicated by red semicircles, a cold front is indicated by blue triangles in the direction of travel. Since a warm front is decelerated by denser and heavier cold air, a cold front always moves faster than a warm one. The warm air zone between the warm and cold fronts is called the Warm Sector. In the end, the cold front catches up with the warm front and an occlusion front is formed at the place of their contact.

5. cold front continues to catch up with the warm one, there is an active mixing of air masses on the occluded front, the warm sector goes into the upper layers of the atmosphere, the pressure in the cyclone core increases. The cyclone gradually ceases to exist.

We looked at the process of cyclone formation from above, let's see what a cyclone looks like in the middle phase of its development in a cross section, what are the signs of an approaching cyclone and the characteristics of a cyclone as a whole:

As a whole formation, at the height of its development, the cyclone moves in the direction of the wind blowing in the warm sector, i.e. moves in the direction of the isobars of the warm sector.

The air plays extremely important role in the life of not only a person, but the whole planet. Atmospheric phenomena have been studied by scientists since the beginning of centuries and continue to be actively investigated today. It is worth saying that, in fact, this is not just a continuous opaque substance, it is divided into masses and fronts, which, moving over various parts, play key role in the formation of air vortices. Consider what a cyclone and anticyclone are, their main differences.

In contact with

Cyclone

A cyclone is an air mass that has the form of a vortex, gigantic in diameter (from 100 to many 1000 km). The cyclone is characterized by low pressure and the movement of air flows clockwise or counterclockwise, in the center, in different directions, depending on the hemisphere in which the vortex operates.

A cyclone differs from an anticyclone by the process of formation. The first has nature occurrence: the planet Earth rotates, due to which the air around it moves and forms vortices. Considering the physics of the occurrence of these phenomena, we can distinguish two main theories in the formation of the air flow:

• Coriolis force;
• fixed point theorem.

Thanks to these theories, it is possible to explain the appearance of such vortices in the earth-air space and also in the atmospheres of others.

Kinds

There are two main types of vortices that differ in their characteristics.

extratropical

Characteristic of polar or temperate climatic zones . Their diameter usually starts from 1000 km at the beginning and several thousand at the end. They, in turn, are divided into:

• southern - they are characteristic of temperate climatic zones, or rather their southern parts. These include cyclones in the Balkans, the Mediterranean and the Black Sea coast;
• northern;
• northeastern.

Of these, only the southern ones carry a colossal amount of energy, which usually results in heavy precipitation, winds, lightning storms and other unpleasant natural phenomena.

extratropical cyclone

tropical

Occur only over tropical zones and are small in size. Their diameter is usually estimated at several hundred kilometers (rarely over 1000 km), but they are characterized by strong winds. Because of this, they often become stormy and are distinguished by the “eye of the storm” - this is the central part of the vortex, which is about 30 km in diameter, in which clear weather remains without winds and precipitation.

Important! and the nearest territory to it are the territory in which such natural phenomena never occur.

A cyclone is low pressure in the atmosphere and all that it entails. Meteorologists can timely predict the imminent onset of such an air vortex. What kind of weather does a cyclone bring: with showers and destructive storms, but warm temperature air is conserved.

tropical cyclone

Anticyclone

What is an anticyclone - this is part of the air flows in which there is high pressure and wind movement in certain directions. Such an area is distinguished by the fact that the wind is directed clockwise in the territory of the upper hemisphere and counter-clockwise in the lower one.

Anticyclones are divided into two types:

• low ones are predominantly cold air flows, in which up to 1.5 km of the troposphere there are closed isobars, and above there is no high pressure at all;
• high - in such air masses, air is warm and high pressure is present throughout the entire troposphere involved. In such vortices there can be several main centers.

An anticyclone is clear weather without clouds. Moreover, low-lying stratus clouds and fogs with frosts at night in autumn and winter can form, and in summer - cumulus clouds and lack of precipitation, which often leads to forest fires. Such eddies do not exceed several thousand kilometers in diameter and move from west to east at a speed of 30-40 km/h, leaning toward low latitudes.

Signs of the presence of an anticyclone are as follows:

• clear sky;
• little or no clouds;
• no wind and rain with snow;
• sunny stable weather.

The formation of such air currents over areas where the soil is covered with ice is reflected in their strength and characteristics. So, over Antarctica it will be extremely strong, and over Greenland it will be much weaker. The same goes for tropical climates.

Anticyclone

Comparison

The prefix anti itself indicates that an anticyclone is an atmospheric phenomenon that is opposite to a cyclone in its characteristics. If a cyclone is low Atmosphere pressure, then the anticyclone is high. This is the most significant difference, drastically changing the weather in the area under these eddies. Their difference lies in the different movements of air currents. How else are they different.

The characteristics of the cyclone and anticyclone are given below.

Thus, the approach of a cyclone indicates that weather is approaching with devastating consequences: heavy rains, winds and snow storms. There will be many clouds and clouds in the sky, strong gusts of wind. In general, the weather will be unstable. Unlike such vortices, anticyclones will bring stability: calm weather will be established, calmness and cloudlessness, it will be warm for a long time.

atmospheric fronts. Cyclones and anticyclones

Cyclone (low pressure area)

Conclusion

Weather-sensitive people often feel the approach of one or another atmospheric phenomenon on themselves: when an anticyclone approaches, atmospheric pressure is high, and blood pressure drops, so dizziness and headaches appear. When a cyclone approaches, the opposite is true: atmospheric pressure decreases, and blood pressure rises.

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 the fronts are key concepts, which will help to display the essence of these weather phenomena.

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 high temperature and increased dustiness. They are responsible for the haze that covers objects when viewed from a distance. Tropical masses formed on the continental part tropical zone, 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, entering such a front may portend either pouring 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 played by a cold mass, then such a 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 temperature. 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 conditions like 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.