Why are there strong winds? “Mom, what is the wind? Dad, why is the wind blowing? - we answer the baby. How wind is formed

Moving in a certain direction. On other planets, it is a mass of gases characteristic of their surface. On Earth, the wind moves mostly horizontally. Classification, as a rule, is carried out in accordance with the speed, scale, types of forces, their causes, places of distribution. Under the influence of flows are various natural phenomena and weather. The wind contributes to the transfer of dust, seeds of plants, promotes the movement of flying animals. But how does directional airflow come about? Where does the wind blow from? What determines its duration and strength? And why do the winds blow? About this and much more - later in the article.

Classification

First of all, winds are characterized by strength, direction and duration. Gusts are strong and short-term movements (up to several seconds) of air flows. If a strong wind of medium duration (about a minute) blows, then it is called a squall. Longer air currents are named according to their strength. So, for example, a light wind blowing on the coast is a breeze. There is also a typhoon. The duration of the winds can also be different. Some last a few minutes, for example. The breeze, which depends on the temperature difference on the relief surface during the day, can last up to several hours. The local and general circulation of the atmosphere is made up of trade winds and monsoons. Both of these types are classified as "global" winds. Monsoons are called seasonal changes in temperature and have a duration of up to several months. The trade winds are constantly moving. They are due to temperature differences at different latitudes.

How to explain to a child why the wind is blowing?

For children at an early age, this phenomenon is of particular interest. The child does not understand where the air flow is formed, which is why it is in one place and not in another. It is enough to simply explain to the baby that in winter, for example, it blows cold wind due to low temperature. How does this process take place? It is known that the air flow is a mass of atmospheric gas molecules moving together in one direction. A small air flow, blowing, can whistle, tear off hats from passers-by. But if the mass of gas molecules has a large volume and a width of several kilometers, then it can cover a fairly large distance. In closed rooms, air practically does not move. And you can even forget about its existence. But if, for example, you put your hand out of the window of a moving car, you can feel the air flow, its strength and pressure with your skin. Where does the wind blow from? The movement of the flow is due to the difference in pressure in different parts of the atmosphere. Let's consider this process in more detail.

Atmospheric pressure difference

So why does the wind blow? For children, it is better to cite a dam as an example. On the one hand, the height of the water column, for example, is three, and on the other, six meters. When the sluices are opened, the water will flow to the area where it is less. The same thing happens with air currents. Different parts of the atmosphere have different pressures. This is due to the difference in temperature. Molecules move faster in warm air. Particles tend to move away from each other different sides. In this regard, warm air is more discharged and weighs less. As a result, the pressure that is created in it decreases. If the temperature is lowered, then the molecules form closer clusters. Air therefore weighs more. As a result, the pressure rises. Like water, air has the ability to flow from one zone to another. So, the flow passes from the area with high pressure to the area with low pressure. That's why the winds blow.

The movement of streams near water bodies

Why does the wind blow from the sea? Consider an example. On a sunny day, the rays warm up both the shore and the pond. But the water heats up much more slowly. This is due to the fact that the surface warm layers immediately begin to mix with the deeper and therefore cold layers. But the coast heats up much faster. And the air above it is more discharged, and the pressure, respectively, is lower. Atmospheric flows rush from the reservoir to the shore - to a freer area. There they, heating up, rise up, again freeing up space. Instead, a cool stream appears again. This is how air circulates. On the beach, vacationers can periodically feel a light cool breeze.

The meaning of the winds

Having found out why the winds blow, it should be said about the effect they have on life on Earth. The wind has great importance for human civilization. The whirling currents inspired people to create mythological works, expanded the trade and cultural range, and influenced historical phenomena. The winds also acted as energy suppliers for various mechanisms and units. Due to the movement of air currents, they were able to overcome considerable distances across the oceans and seas, and balloons across the sky. For modern aircraft, winds are of great practical importance - they allow you to save fuel and increase it. But it should be said that air currents can also harm a person. So, for example, due to gradient wind fluctuations, control over the control of the aircraft can be lost. In small bodies of water, fast air currents and the waves they cause can destroy buildings. In many cases, winds contribute to the expansion of the fire. In general, the phenomena associated with the formation of air currents, different ways affect wildlife.

Global Effects

In many areas of the planet, air masses with a certain direction of movement predominate. In the region of the poles, as a rule, eastern winds prevail, and in temperate latitudes - western winds. At the same time, in the tropics, air currents again take an easterly direction. On the borders between these zones - the subtropical ridge and the polar front - there are so-called calm areas. There are practically no prevailing winds in these zones. Here the movement of air is carried out mainly vertically. This explains the appearance of high humidity zones (near the polar front) and deserts (near the subtropical ridge).

Tropics

In this part of the planet, trade winds blow in a westerly direction, approaching the equator. Due to the constant movement of these air currents, the atmospheric masses on Earth are mixed. This can manifest itself on a significant scale. So, for example, the trade winds moving over Atlantic Ocean, carry dust from the African desert territories to the West Indies and parts of North America.

Local effects of air mass formation

Finding out why the winds blow, it should be said about the influence of the presence of certain geographical objects. One of the local effects of the formation of air masses is the temperature difference between not too remote areas. It can be provoked by different coefficients of light absorption or different heat capacity of the surface. The latter effect is most pronounced between and land. The result is a breeze. Another local factor of importance is the presence of mountain systems.

Mountain influence

These systems can be a kind of barrier to the movement of air flows. In addition, mountains in many cases themselves cause wind formation. The air above the hills warms up more than the atmospheric masses above the lowlands at the same height. This contributes to the formation of low pressure zones over mountain ranges and wind formation. This effect often provokes the appearance of mountain-valley atmospheric moving masses. Such winds predominate in areas with rugged terrain.

An increase in friction near the valley surface leads to a deviation of the parallel directed air flow to the height of the nearby mountains. This contributes to the formation of a jet high-altitude current. The speed of this flow can exceed the strength of the surrounding wind up to 45%. As mentioned above, mountains can act as an obstacle. When bypassing the circuit, the flow changes its direction and strength. Changes in mountain ranges have a significant impact on wind movement. For example, if there is a pass in the mountain range that the atmospheric mass overcomes, then the flow passes it with a noticeable increase in speed. In this case, the Bernoulli effect works. It should be noted that even slight elevation changes cause fluctuations. Due to a significant air velocity gradient, the flow becomes turbulent and continues to remain so even behind a mountain on a plain at a certain distance. Such effects are in some cases of particular importance. For example, they are important for aircraft taking off and landing at mountain airfields.

General circulation of the atmosphere- a system of air currents on the globe, which contributes to the transfer of heat and moisture from one area to another. Air moves from areas of high pressure to areas of low . Areas of high and low pressure are formed as a result of uneven heating of the earth's surface. Under the influence of the rotation of the Earth, air flows deviate to the right in the Northern Hemisphere, and to the left in the Southern Hemisphere.

IN equatorial latitudes, due to high temperatures, a belt constantly exists low pressure with weak winds. The heated air rises and spreads at a height to the north and south. At high temperatures and upward movement of air, with high humidity, large clouds form. There is a lot of rainfall here.

Approximately between 25 and 30 ° N. and yu. sh. air descends to the surface of the Earth, where, as a result, belts are formed high pressure. Near the Earth, this air is directed towards the equator (where the pressure is low), deviating to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This is how trade winds. In the central part of the high-pressure belts, there is a calm zone: the winds are weak. Due to the downward currents of air, the air is dried and warmed up. The hot and dry regions of the Earth are located in these belts.

IN moderate latitudes centered around 60°N. and yu. sh. pressure low. The air rises and then rushes to the polar regions. In temperate latitudes, western air transport predominates (the deflecting force of the Earth's rotation acts).

Polar latitudes are different low temperatures air and high pressure. The air coming from temperate latitudes descends to the Earth and again goes to temperate latitudes with northeasterly (in the Northern Hemisphere) and southeasterly (in the Southern Hemisphere) winds. There are few rainfalls.

Winds

Wind- horizontal movement of air relative to the earth's surface. It results from uneven distribution atmospheric pressure and its movement is directed from areas of higher pressure to areas of lower pressure. The reason for the occurrence of wind is the difference in pressure between the territories, and the reason for the difference is the heterogeneity in heating. The direction of the wind is determined by the part of the horizon from which it blows (the north wind blows from north to south). The direction of the winds is affected by the deflecting force of the Earth's rotation.

The winds are varied origin, nature, meaning . The general circulation of winds, due to the difference in atmospheric pressure, includes: monsoons, zonal transfers, cyclones, anticyclones. The local circulation of the atmosphere is expressed in breezes.

Types of winds.

TO local winds include breezes, mountain-valley, hair dryers, bora, sirocco, simum, etc. IN equatorial belt low pressure prevails, in the subtropical - increased, so the winds blow towards the equator. Under the influence of the Coriolis force, they deviate in the northern hemisphere to the right and have a northeast direction, in the south - to the left and become southeast.

Föhn- warm, dry and gusty wind from the mountains. It blows when pressure is lower on one side of the ridge than on the other. Bora- a strong, cold, gusty wind, which is formed if the cold air crosses over low ridges to the warm sea.

trade winds– constant winds in the tropical regions of the Northern and Southern Hemispheres, blowing from high pressure zones (25-35 ° N and S) to the equator (into the low pressure zone). Under the influence of the rotation of the Earth around its axis, the trade winds deviate from their original direction. In the northern hemisphere they blow from the northeast to the southwest, in the southern hemisphere - from the southeast to the northwest. The trade winds are characterized by great stability of direction and speed.

In temperate latitudes of both hemispheres, westerly transfers dominate ( westerly winds). The temperate westerly winds are the prevailing winds blowing in temperate zone approximately between 35 and 65 degrees north and south latitude. These winds blow predominantly from west to east, more specifically from the southwest in the Northern Hemisphere and from the northwest in the Southern Hemisphere.

The land warms up during the day faster than the sea The air above it is warmer than above the water. An area of ​​low pressure forms above the ground, an area of ​​high pressure forms above the water, and the wind blows from the sea to land. This afternoon breeze. At night, the land cools faster than the sea, over which an area of ​​low pressure forms, and the wind blows in reverse side - night breeze.

The formation mechanism is similar monsoons- seasonal winds that change their direction twice a year: in summer they blow on land, in winter - on the sea. In winter, the air over land is colder, over the ocean - warmer. Therefore, the pressure is higher over the mainland, lower - over the ocean. Therefore, in winter, the air moves from the mainland (area of ​​​​higher pressure) to the ocean (over which the pressure is lower). In the warm season - on the contrary: monsoons blow from the ocean to the mainland. Therefore, in the areas of monsoon distribution, precipitation usually falls in the summer. Due to the rotation of the Earth around its axis, the monsoons deviate to the right in the Northern Hemisphere, and to the left in the Southern Hemisphere from their original direction.

Special systems of winds.

As a result of uneven heating of the earth's surface and the deflecting force of the Earth's rotation, huge (up to several thousand kilometers in diameter) atmospheric vortices are formed: cyclones and anticyclones. Cyclone - atmospheric vortex With reduced pressure in the center. Anticyclone- atmospheric vortex with high blood pressure in the center.

Cyclone – an ascending vortex in the atmosphere with a closed region of low pressure, in which winds blow from the periphery to the center (counterclockwise in the Northern Hemisphere, clockwise in the Southern Hemisphere). The average speed of the cyclone is 35-50 km/h, and sometimes up to 100 km/h. In a cyclone, the air rises, which affects the weather. With the appearance of a cyclone, the weather changes quite dramatically: winds increase, water vapor quickly condenses, giving rise to powerful clouds, and precipitation falls.

Anticyclone - a descending atmospheric vortex with a closed area of ​​high pressure, in which winds blow from the center to the periphery (in the Northern Hemisphere - clockwise, in the Southern - counterclockwise). The speed of movement of anticyclones is 30-40 km/h, but they can linger in one place for a long time, especially on the continents. In the anticyclone, the air descends, becoming drier when warmed up, since the vapors contained in it are removed from saturation. This, as a rule, excludes the formation of clouds in the central part of the anticyclone. Therefore, during the anticyclone, the weather is clear, sunny, without precipitation. In winter - frosty, in summer - hot.

Wind speed scale (Beaufort scale)

Lesson summary " Wind. wind systems". Next topic:

Irina Tulenkova
Cognitive experimentation session "Why does the wind blow?" (senior group)

Municipal state preschool educational institution

Kindergarten "Fairy tale".

cognitive experimentation.

Subject: « Why does the wind blow?»

Tulenkova Irina Yurievna

Educator II

qualifying

MKDOU d / s "Fairy tale"

Tyumen region,

Kondinsky district,

With. Leushi, st.

Volgograd. 56,

tel. (34677) 37-134

With. Leushi 2011

Target: introduce children with the cause of wind - the movement of air masses.

Tasks:

1. Clarify children's ideas about properties air: hot rises up - light; cold sinks down - it is heavy.

2. Consolidate children's knowledge of the air.

3. Develop skills for conducting experiments.

4. Improve breathing technique skills.

5. To lay in children the initial elements of ecological culture.

6. introduce children with such a natural phenomenon as wind, its role in the life of nature and man.

7. Cultivate a culture of communication, activate speech activity. Methodical tricks We: Experiments conducted by the teacher together with the children; art word (riddles, poems about the wind); breathing exercises; physical training; a game; surprise moment; result; analysis.

caregiver: Guys, let's close our eyes and listen, what do you hear? Children: (children's answers).

And I hear the rustle of leaves and imagine how our the breeze flies to the group, fresh, light. Do you hear?

Or maybe you and I will turn into trees and imagine that breeze shakes our branches.

Fizminutka: « The wind blows in our face» .

caregiver: Guys, while we were listening breeze he visited us in group and brought us a balloon. Let's see what is written there. (The teacher reads the note attached to the ball). Here is a riddle, carefully listen:

We need him to breathe To inflate the balloon With us every hour But he is invisible to us.

What is this? (air)

That's right, it's air. And today we will talk about air, we will conduct experiments like real scientists. And for this we have a laboratory of air transformations.

(go to the lab)

caregiver: Guys, who saw the air? Maybe it doesn't exist at all? (children's answers) Let's check it out with you now.

with BAGS Educator: What do we have in the bags?

Children: Air.

caregiver: What is he like? Do we see him? Why can't we see him? Why is he called invisible?

Children: The air is transparent, so you can see everything through it.

caregiver: Guys, look what I have?

Children: Cup.

caregiver Q: What is it made of?

Children: From glass.

caregiver: So the glass is glass. Look through it, you see

anything.

Children: Yes!

caregiver: So, what kind of glass?

Children: Transparent.

caregiver: Do you think this glass is empty? Is there anything in it?

(children's answers)

caregiver A: We'll check it out.

WITH GLASS

caregiver: There are bowls of water and glasses on the table. It is necessary to turn the glass upside down and slowly release it into the bowl. The glass must be held very evenly. What happened? Does water get into the glass? Why not. (children's answers) caregiver: We learned that there is air in the glass and releases water into it. And now we tilt the glass a little, what appears in the water?

Children: (bubbles)

caregiver: That's right, air comes out of the glass, and water takes its place. How else can you see the air?

(children's answers)

caregiver: Let's take a tube, dip it into the water and blow. What comes out of the water with bubbles?

Children: Air.

caregiver: Right. We exhaled air, because all people breathe air. When we simply inhale and exhale air, do we see it? Children: No!

caregiver: (takes a napkin). Can you see it with a napkin?

Children: Yes!

caregiver: And you can also see how we breathe in winter - what comes out of our mouths? Children: Steam.

caregiver: Let's show you how our noses breathe.

Breathing exercises:

1. "Breath" Breathe with one nostril and peace will come to you.

I. p. - standing, the body is straightened, but not tense; close the right nostril with the index finger right hand, take a long long breath with the left nostril, as soon as the breath is over, take a long breath through the nose (4 times,

The same exercise with the left nostril.

2. "Breath". Quiet. Quietly we will breathe, we will hear our heart.

I. p. - about. With. - slowly inhale through the nose, hold the breath for 4 seconds, exhale smoothly through the mouth (2 times).

3. « Air balloons» . Now let's check if we have a lot of air in our chest. Let's inflate balloons (children inflate balloons and hold them). Now let's let go a little, how do you feel?

Children: Wind.

caregiver: That's right, it's wind. Guys, do you know what wind?

(children's answers)

caregiver: Wind- this is the movement of air, it is around us, we do not see it, but it is necessary for all living beings. The wind has power. He knows how to move ships, inflate sails, rotate mills, bend trees. Can it wind hurt a person?

(children's answers)

caregiver: Right, the wind is different: hurricane, tornado, dry wind, can harm people, and easy calm breeze brings coolness. yj over the seas the wind is rushing,

The sails fly like birds.

And salty, like a whim It is called - (breeze).

The wind is strong and mighty,

He gathered clouds over the house,

The rain beats like a drum

Conductor -

(Hurricane).

If the wind blows hot,

He calls -

(dry wind)

He drives sand and dust

Oppression to the ground in the steppe feather grass.

This wind, everyone needs to know

It's called - (tornado) He captured everyone with a whirlwind He twisted from all sides.

Ellie in a fairy tale he sped away

And suddenly fell silent.

caregiver: Do you want to become the wind for a few minutes?

WITH KARABLIK.

caregiver: Our bowls turn into the sea. And you will be the winds. Let's get on the water. What happens?

Children: Waves.

caregiver: The stronger The wind's blowing, the more waves (but in everything you need to know the measure). Now let go sailing ships ki, if you blow on it, what will happen?

Children: The boat is sailing.

caregiver: Likewise, large sailing ships move due to the wind. What happens to the boat if there is no wind? And if the wind is very strong?

Children: Starts wind and the ship may be wrecked.

caregiver: And now let's take a fan and wave it over the water. Why did the waves appear? The fan moves and pushes the air. The air also starts to move. Means wind is the movement of air. Why does air move? Let's do one more experiment.

WITH A CANDLE.

caregiver: Hold the candle and put it on a stand on the table. Let's place it in the lamp glass, under which we put the bars. Hold your hand over the lamp glass. What do you feel about it?

Children: Air comes out of the lamp glass.

caregiver: Now let's hold a piece of paper cut into thin strips under the lamp glass. What will happen?

Children: The strips are tilted up.

caregiver: So the air is heated and the heated air rises. Guys, what do you think, if we open the door, will the breeze?

(children's answers)

caregiver: Let's check.

WITH A CANDLE.

caregiver: We bring a lit candle to the ajar door. If you hold the candle over the top edge of the door, then the flame of the candle will deviate towards the street.

If the candle is placed on the floor, then the flame will deviate to the side. groups. This means warm air is light, it flows out of our groups on the street, and its place is taken by a cold one.

So it is on the street. Our Earth is heating unevenly. Where it heats up more, streams of warm air form, which rush upwards, and streams of cold air rush in their place. And so it turns out wind. Or maybe it happens that all the air in the yard heats up and flies away, and we will have nothing to breathe?

(children's answers)

Leading: That's right, this will not happen if the sun warms us, then at the same time the weather is cold somewhere. And the air is colder there, which means heavier. Therefore, cold air rushes to where it is warmer, and warm air has already made room, rising up. This is how it turns out wind

(show diagram.)

It's clear now who's pushing wind who makes the air fly from place to place? Didn't guess? Then I'll tell you - it's the sun. It warms the earth (evenly) the same, always somewhere colder. And if the Earth had the same temperature, then there would be no breeze. The clouds would stop. If there were no rain, there would be a drought. Smoke from cars and factories would hang over the cities. So bad weather is not so bad. Indeed, at this time, the sun is shining merrily for other children far from us.

caregiver: And how can we determine if the street wind?

Children: Through the trees, with the help of a ribbon, a weather vane on the house, a turntable. caregiver: Well done guys, we learned a lot of interesting things, let's remember what we are with today met?

What experience did you like best?

What can you praise yourself for?

caregiver: To consolidate our knowledge, I give you a turntable and, going out into the street, we will determine if there is the wind outside and how it blows.

The relationship between man and the wind has always been extremely closely related to each other. It is from this natural phenomenon in prehistoric times (as, indeed, even now), human life often directly depended. With its help, mankind was able to develop crafts and make their lives much easier, which can be observed even in such a banal example as a windmill. There is nothing surprising in the fact that as long as mankind has existed, so many people have asked and still ask themselves and each other the question, why does the wind blow?

This riddle is still extremely difficult not only for understanding a child, but also an adult. Scientists who study inanimate nature are still arguing about why the wind blows, where the wind blows from and where the wind blows.

The Scientific and Technical Encyclopedic Dictionary defines wind as a stream of air masses (a mixture of gases whose particles fly freely in space), which quickly moves parallel to the Earth's surface. Another interpretation of the wind suggests that the wind is a natural phenomenon that causes air masses to move due to certain changes that occur in the environment.

Wind is generated due to the uneven distribution of pressure in the atmosphere. As soon as it appears, it immediately begins to move from the high pressure zone to the low pressure zone. To put it simply, why the wind blows, then we can safely say that if it were not for the Sun, land and the World Ocean of our planet, then the air after a rather short time would begin to have the same temperature and humidity everywhere, which is why the wind did not blow would never.

How air masses move

Throughout the day, the surface of our planet heats up unevenly. This applies not only to objects that are at a distance from each other, but also to those that are located very close. For example, over the same period of time, things of a darker color heat up (absorb heat) much more than light ones. The same can be said when comparing water with land (the latter reflects less of the sun's rays).

In turn, heated objects unevenly transfer heat to the air that surrounds them. For example, since the earth heats up much more than water, during the day air from the earth rises, and colder air from the sea goes to its place. At night, the reverse process occurs - while the earth has cooled, the waters of the sea remain warm. Accordingly, the warm air above the sea goes up, and the air from the land goes to its place.

Warmer air rises where it collides with colder air. This happens because the heated air becomes light and tends to rise, while the cold one, on the contrary, becomes heavier and rushes down. The greater the difference between the temperatures of the cold and warm stream, the stronger the wind usually blew. Thus, not only a light breeze arises, but also small whirlwinds, hurricanes and even tornadoes.

The air itself tends to be the same everywhere. When a certain heterogeneity is formed (it is warmer in one place, colder in another, in the third - there are more particles of gases, in the fourth - less), it moves horizontally, trying to eliminate the "inequality".

A similar process is taking place throughout the globe. Most warm place on our planet is the equator. It is here that the heated warm air goes up all the time, and from there it goes either to the North or South Poles. After that, at certain latitudes, it descends again to the earth and begins to move. Where exactly the wind blows - depending on the circumstances. Maybe further to the poles, or maybe return to the equator.

Earth rotation

The rotation of our planet affects the flow of air masses. It is because of him that all the winds that blow in the Northern Hemisphere shift to the right, and in the South - to the left.

Atmosphere pressure

Our body, without even knowing it, all the time feels the pressure of air on itself - despite the fact that it seems to us absolutely weightless. According to the latest scientific data, the entire atmosphere of our Earth (in other words, a layer of gases), consisting mainly of nitrogen and oxygen, weighs five quadrillion tons.

Atmospheric pressure in different parts of the Earth is different. Gas molecules strive to compensate for this, and constantly move at great speed in different directions (these particles, due to the Earth's gravity, are completely attached to it, and cannot fly into space in any way).

This is how it turns out that the wind is the movement of a huge number of atmospheric gas molecules in one direction. air masses usually flow from a zone of high pressure (when the air is cold - an anticyclone) to an area of ​​low pressure (when it is warm - a cyclone), thereby filling the voids of rarefied air.

Wind classification

Strong winds that have an average duration (one minute) are squalls. There are such types of winds:

• Breeze - a warm wind near the sea, where you can observe a light wind blowing on the coast. Wind direction changes twice a day. Day (or sea) often blew from the sea to the shore, night (or coastal) - vice versa. The breeze speed is usually between 1 and 5 m/s;
• A storm is an extremely strong wind with a speed of 16 to 20 m/s.
• Storm - occurs during a cyclone, speed - from 15 to 32 m / s;
• A hurricane is a very strong storm caused by air masses moving in different directions at great speed, the speed of which is from 32 m/s;
• A typhoon is a hurricane of enormous destructive power that blew and blows mainly off the east coast of Asia, on Far East as well as the Western Pacific.

Wind gusts are short-term (several seconds) and strong (several hours or even months) movements of air masses. For example, for a tropical climate, the following types of winds are distinguished:

• Monsoons - winds, characteristic mainly for tropical areas, blow for several months, sometimes changing the direction of the wind. In summer - from the ocean to land, in winter - vice versa. The summer monsoons are characterized by high humidity.
• Trade winds - such a wind usually blew and blows in tropical latitudes throughout the whole year, in the Northern Hemisphere - from the northeast direction, in the South - from the southeast. A windless strip separates them from each other.

Due to the constant change in pressure, the direction of the wind is constantly changing. But in any case, the wind always moves from an area of ​​high pressure to an area of ​​low pressure.

For thousands of years, people have been watching the winds, drawing certain conclusions, putting forward hypotheses, and drawing up graphs in order to use this amazing phenomenon as best as possible in their activities. inanimate nature. So, the so-called Wind Rose appeared - a drawing, more precisely, a diagram that depicts exactly how the wind blows in a particular area.

The Wind Rose is composed in this way: eight straight lines are drawn from the center at a distance of 45 ° from each other, on which marks are applied with a length proportional to either the frequency of the winds or their speeds. After that, the ends of the marks are connected and two polygonal figures are obtained - the Rose of the frequency of winds, and the Rose of the speed of the winds.

The wind rose makes it possible to determine the direction, strength, and duration of the prevailing wind, as well as the frequency of air currents. The wind rose is drawn both in order to determine the average indicators, and to determine the maximum values. You can create a complex drawing on which diagrams will be plotted, consisting of several parameters at once, which will also show which direction the wind is blowing.

The drawings are extremely necessary for a person– during construction, to solve various economic problems (for example, in Lately thanks to the wind, it became possible to receive electricity), etc. After all, the wind may well be both a friend and an enemy - if you do not pay attention to it and do not take into account its influence on environment, he is quite capable of causing irreparable damage, destroying the creation created by man. Although the wind is a phenomenon uncontrollable by man, since he blew and will blow wherever he wants, but now humanity can predict its approximate direction and strength, which can save many lives.

What is wind? It's complicated atmospheric phenomenon that occurs under certain conditions. Why is this atmospheric phenomenon? Because the area of ​​occurrence of this phenomenon is the lowest atmospheric layer - the troposphere (8-12 km above the earth's surface).

The concept of wind and its features

Wind is the movement of air, and not just movement, but its movement in a horizontal direction above the earth's surface. When the pressure in different points of the globe is different, the air masses tend to be distributed over the earth's surface more evenly and fill the place where the atmosphere is not so dense.

Atmospheric pressure itself is the air pressure on earth's surface by the attraction of air masses to the Earth. In this case, the gravitational force acts, which keeps the air near the surface of the Earth, and allows people and objects to come into close contact with the earth, and not fly away into space.

Based on the foregoing, we can conclude that the wind moves not only horizontally above the Earth's surface, but also from the area of ​​high atmospheric pressure to the area of ​​low pressure.

The air heats up extremely unevenly - this is partly due to the constant presence of winds on the planet.

Most air masses warm up at the Equator - the central latitude of the Earth. From there, the winds are already distributed over the entire earth's surface.

Strength and speed of the wind

The wind cannot be seen, but it can be felt, for example, its strength or the speed with which the wind blows off a hat from the head or ruffles the leaves on the trees. It is not for nothing that the verbal expression "wind knocked down" is sometimes used, meaning that the wind was very strong.

Wind speed is expressed in terms of "meter per second", "kilometer per hour", and its speed can also be expressed on a point scale.

There is a so-called Beaufort scale- a twelve-dimensional scale developed by the World Meteorological Organization to measure wind speed by the waves it creates in open water spaces (most often at sea) and the force of impact on ground objects.

With the Beaufort scale indicator "0", the wind speed reaches about 0-0.2 m/s and is characterized by calmness. The leaves of the trees do not move.

With a Beaufort scale indicator of "4", the wind is considered moderate at a speed of 5.5-7.5 m/s. On the ground, the strength of such a wind is seen as follows: a strong air current raises dust and debris and rolls them along the road, and also sets the branches of trees in motion.

A storm with wind speed on the Beaufort scale occurs at the number "9": trees begin to uproot on the ground and rooftops collapse.

Varieties of wind

There are several types of winds as currents of air masses over giant areas: monsoons, trade winds, foehn, breeze, bora.

Monsoon is a wind with clearly defined periods of activity. Air masses under this name blow from land to sea in winter, and from sea to land in summer. The wind is rich in moisture. Its localization is mainly Asia.

trade wind A type of wind that blows between the tropics. The time of his observation all year round. On a 12-point scale, this wind blows with a force of 3-4.

Breeze- a warm wind with less localization than, for example, a monsoon or a trade wind. The breeze mainly blows at night from the shore to the sea, during the day from the sea to the shore. The direction can change several times a day.