Wind is a physical phenomenon. What is wind - types, how it arises, meaning

The wind always blows from places with high air pressure to those places where Atmosphere pressure less.

breezes

breezes(French "brise"- light wind) - these are winds blowing from the sea to land during the day, and from land to sea at night.

The surface of the earth is heated unevenly. On a summer day, for example, the land surface heats up more. When heated, the air expands and becomes lighter. Part of the heated air rises, and the colder air from the sea begins to move towards the land. Such a wind is called a daytime breeze (Fig. 113). If at this time atmospheric pressure is measured over land and over the sea, it turns out that over land it will be less.

If you measure atmospheric pressure in the evening, then it will be less over the sea, since the water in the sea is warmer at night, and the air also heats up from it. This means that the night breeze will blow from land to sea (Fig. 114).

tropical winds

• Trade winds.
• Monsoons are winds that blow from land to sea in winter and from sea to land in summer.

In order to correctly predict the weather, it is very important to know the direction and strength of the wind. The north wind brings cooling, the south - warming, the wind from the sea does not set moisture, dry winds blow from arid regions.

Direction of the wind

They call the wind according to the side of the horizon where it blows: if the wind blew from the northwest, then they say that it is northwest, if from the southwest - southwest.

Determination of wind direction

The direction of the wind can be determined by a waving flag, by the direction of the smoke coming from the pipes, but more accurately this can be done using a weather vane (Dutch "weather vane" - wing) - a device for determining the direction and strength of the wind.

The arrow of the weather vane (it is called a weather vane) rotates freely on the rod and with its sharp end is always directed against the wind. Below the arrow, eight rods are fixedly attached - indicators of the main and intermediate sides of the horizon.

wind force

The strength of the wind is not always the same. On some days the wind is barely noticeable, on others it is so strong that it will uproot the trees. Observations have shown that if between two places on the globe pressure difference is small, then the wind will be weak. If the difference in pressure is large, then the wind will be strong.

This means that the greater the pressure difference between two adjacent parts of the earth's surface, the faster the air moves from a place with high pressure to a place with less pressure, the stronger the wind will be.

Determining the strength of the wind

Together with the arrow of the weather vane, the frame, fixed above the weather vane, also rotates. In this frame, a metal plate hangs freely, attached to the upper end. The stronger the wind, the more the plate deviates from its usual position. By the deviation of the plate and judge the strength of the wind. The strength and speed of the wind can be determined approximately (Fig. 115).

Building a wind rose

In order to compile a wind rose (Figure 117), you must first draw a diagram showing the main and intermediate sides of the horizon. Starting from the center, set aside on the line showing the direction to the north as many segments of half a centimeter as in the studied period of days when the north winds were blowing, then on the line showing the direction to the northeast, set aside as many of the same segments as there were northeast winds. Do the same for all directions. Now connect the ends of the resulting segments in each direction, and you will get a drawing, from which you can immediately determine which winds prevailed in this period of time. material from the site

The wind plays an important role in our life. If there were no wind, the clouds would burst into rain in the place where they arose. Over the oceans, where there is already more than enough moisture, showers would not stop, and not a drop of rain would fall on land. This wind brings life-giving moisture to the fields and forests, thanks to the wind, rivers and lakes do not dry up. What about warm ocean currents? They also owe their origin to the wind. The wind purifies the air we breathe. Exhaust gases from automobile engines, smoke from factories and factories, carbon dioxide released during the breathing of humans and many other living organisms - all this greatly pollutes the air. The wind carries away this polluted air, and in return it brings clean.

wind turbines

Since ancient times, man began to use the power of the wind. Ancient Egypt already had wind turbines for grinding grain and for lifting water from the Nile to the fields. On sailing ships, brave sailors made long journeys.

In arid areas, wind turbines drive pumps that supply water to the fields, and where the area is swampy, wind turbines help drain it (Fig. 116).

Wind turbines are widely used at the stations of polar explorers wintering on the islands of the Arctic Ocean and in Antarctica. Despite the severe frosts, wind turbines work there without fail. They always give polar explorers light and warmth, feed their radio installations with current.

Every inhabitant of the planet probably knows what wind is. Going outside at any time of the year, you feel the air flow.

What is wind

it movement of a large volume of air in a horizontal direction.

Along with the movement of air, water vapor and dust follow. The air flow is also characterized by a certain temperature.

How wind is formed

Let's figure out where the air movement comes from. Sun rays, passing through the atmosphere, do not heat it. Air is heated from the earth's surface. Water and land heat up at different rates. Water mass absorbs heat more slowly, drying faster.

Above the earth's surface warm time year the air is always warmer. Where it is warm, low atmospheric pressure forms. High atmospheric pressure is established above the water surface.

Air moves towards areas with low atmospheric pressure. This movement is called wind.

Direction of the wind

It may have different directions. It is considered where the air mass is moving from, it has such a direction.

Do you know where on earth the south wind always blows? Of course, in the north, the north pole, where any side is south.

How to draw a diagram of wind formation

To explain how wind occurs, you can draw a schematic drawing. To do this, it is better to use the border area. We conditionally depict land, next to it is the sea.

Above the earth's surface, the air temperature is higher, the pressure is lower. The heated air is light, it spreads upwards. Over water, the air heats up for a long time. Having more low temperature, the air weighs heavier. High atmospheric pressure is set. Cold air moves from the sea towards the land.

AT winter time the opposite happens. Water cools very slowly. The air will be warmer over the sea, low pressure is established.

Above the earth's surface, the air is cold and the pressure is high. This means that the air will move to the sea. Such a scheme is understandable for children, it helps to deal with the question: “Why is the wind blowing?”.

Types of winds

There are on the planet different types movements air masses with different characteristics. Constant currents blow in the same direction all year round.

There are local movements, in a certain territory. All of them affect the climate. local winds bear various names.

Below are the most famous names of the winds with a short description:

Human use of the wind

The importance of moving air masses is great. They influence the climate.

Since ancient times, people have used the power of moving air for navigation, the operation of windmills. Now the strength of the wind is important for the development of some sports.

Air currents of great strength are alternative source energy. Wind turbines can generate electricity without fossil fuels.

What winds are seasonal and permanent

Seasonal air currents change their direction according to the seasons of the year. Monsoons are such air currents.

The constant movement of air does not depend on the seasons of the year. Both in winter and summer they move in the same direction. These include the trade winds and western transport, as well as the movement of air from the poles towards temperate latitudes.

Constant winds are related to the distribution of high and low pressure on the planet.

What determines the speed and strength of the wind

The wind has different speed and strength. Speed ​​is measured in m/s or km/h. To determine the strength of moving air, a scale in points has been developed.

Pressure drops in the atmosphere are different. The strength of the air flow depends on these differences. The airflow rate will be faster if the pressure difference is large.

The moving air acts on everything that it meets in its path. The larger one value, the larger the other will be.

Consider the main indicators:

1. Strong wind are valued at 6 points. The speed of gusts reaches 39-49 km/h. Large waves form on the sea, trees sway on land.
2. A very strong wind is estimated at 7-8 points. The speed of air gusts reaches 50-60 km / h. Tree branches break, tiles and slates can be torn off the roofs of houses.
3. The strongest wind is called a hurricane. On dry land, it is rare. Estimated 12 points. Gust speeds can reach over 100 km/h. This air current causes great destruction.
4. The maximum speed of gusts is associated with tornadoes. It is over 400 km/h.

What winds cause the formation of various currents

Air currents that constantly blow over the oceanic expanses form currents. Such movements of water form the western transport, trade winds, monsoons.

Conclusion

The movement of air masses is an inevitable process present in the atmosphere. They shape the climate. Sometimes such movements have destructive power. A person studies wind phenomena, gives them names, but cannot control the elements.

"Wind, wind! You are mighty ..." - every fifth grader knows this by heart. What is your power, where does it come from, how are you born yourself, wind-breeze-breeze? Time, as elusive as you, runs and changes century after century, and people all ask the same question: "What is the wind, where does it come from?" Others answer something to them, each in his own way. "The wind is born from the trees," someone says, "the trees sway and drive the air." This version is very cute, but is someone shaking the trees? "Like who? - answers the hero of the story - God!"

If this is idle curiosity - it sounded and was forgotten. The wind-breeze is blowing on the street - it means that it should be so. But what determines your strength and why are you sometimes light and playful, sometimes angry and cruel? This is already a serious question; it is not for nothing that the best scientific minds are constantly studying what wind is, and on what factors its intensity and direction depend. Thanks to their discoveries, a person today can predict in which direction, with what force you will blow. But you don't let yourself be deceived: isn't the effect of surprise your favorite game?

Sometimes it seems that there are no secrets here. After all, what is the wind? In short, the movement of the atmosphere. That is, the flow of air molecules from And what drives these molecules is a topic for a more detailed explanation. In places where warm air accumulates, atmospheric pressure is reduced. Air heated by the sun rises to the upper layers of the atmosphere and cools there, then, according to the principle of circulation, descends, carrying with it the region high pressure. These temperature differences create the movement of the atmosphere, called the wind. The stronger the drops, the stronger the wind.

Why is it always windy in the mountains and on the coasts? Because in places of contrasting atmospheric pressure, the circulation of warm and cold air currents occurs continuously, only its intensity changes. This is especially noticeable on the seashore, where you, the wind, frolic day and night. And all because the sun heats the land faster, while the water column warms up slowly. Warm wind rises above the ground in streams, giving way to a cold air stream from the side of the water. And the wind starts to blow. This is the wind from the sea that blows constantly. Although no, at night the reverse movement begins: the land cools faster, and the sea still stores heat, and now the wind changes direction - from the coast to the sea.

You are having fun, wind, because our knowledge is too narrow. There are other hypotheses about what the wind is. There is a so-called which also characterizes the movement of air currents during the rotation of the Earth. According to the French scientist Gaspard-Gustave Coriolis, our planet rotates at a higher speed than its atmospheric layer and is deflected, creating flows. And there are also eternal, or dominant winds blowing along the equator and from the poles of the Earth.

They say that a person knows three percent of things. Does he know? What do you think, wind-breeze-wind wind? Or we don’t need to know anything, it’s better to dwell on simple knowledge: there is a wind, because the trees sway, but God sways them ...

In the arsenal of the vagaries of the weather, one of the main places, of course, is reserved for the wind. It can be warm and gentle, or it can blow with such force that the air current tears roofs off houses and carries away household utensils.


He brings rain with him, or vice versa, disperses the clouds hanging over the city, returning blue sky and . The wind among all peoples symbolizes a free nature, not subject to attachments and obligations.

He obeys only his desires, is unpredictable and can turn out to be both a friend and an enemy. But what is the wind in fact, how does it arise and can it be subdued?

What is wind?

From a scientific point of view, wind is the movement of air mass from an area of ​​high pressure to an area reduced pressure. As a rule, these movements are directed horizontally.

Although there are ascending and descending air currents that form atmospheric pressure drops in different parts planets, they are not usually called winds. In addition to pressure drops, the speed and direction of the winds are somewhat influenced by ocean currents, the rotation of the Earth, terrain, and other factors.


Until now, meteorologists have not learned how to predict the behavior of atmospheric air masses, the origin of winds and their further behavior with sufficiently high reliability. Satellite imagery is of great help in this, but it only captures the ongoing processes.

People still have not learned to accurately guess the origin and direction, and even more so to control the "behavior" of winds and hurricanes, but the general patterns of movement of air masses have already been sufficiently studied.

How do winds appear?

During daylight hours The sun gives the Earth's surface a huge amount of thermal energy, heating the land and the thickness of the oceans. But this heating is extremely uneven and depends on many factors.

The most important of them is the distance to the Sun: the equatorial regions, due to the fact that the axis of rotation of the Earth is located vertically to its orbit, are a little closer to the star, and more energy gets to their share than the poles.

The land warms up during the day better than the body of water, but the water retains thermal energy better.

All this leads to atmospheric air, which heats up mainly from the surface of the planet, turns out to be warmer in some places than in others. The heated air rushes up, creating a rarefied space, more cold air from the neighboring area.


Colliding with each other, warm and cold air currents sometimes form squalls, whirlwinds and even tornadoes. These processes take place over the entire surface of the planet, which, when viewed from above, resembles a seething cauldron, where air currents collide and swirl in various directions, dragging the white foam of clouds with it.

Direction of the wind

If the surface of the Earth everywhere was heated equally, we would not have the whims of the weather. Air currents would move only in the vertical direction: cold - down, and warm - up. However, heating proceeds in different ways: in the equatorial region, the air is always well heated and rises, and cold masses from colder regions rush to replace it.

Collisions of these masses occur in different parts of the planet, but they always lead to the formation. Air currents choose different directions, depending on the accompanying circumstances.

The main factors influencing the direction of the winds are the rotation of the planet and the difference in atmospheric pressure. It has been established that in the regions of the poles, the dominant wind direction is east, and in temperate zone The northern and southern hemispheres are dominated by westerly winds.

The tropics are dominated by the winds east direction. Between these main zones of wind formation there are four belts of relative calm - two subpolar and two subtropical, where the air moves mainly vertically: the heated air goes up, and the cold one descends to the surface of the earth.


Winds play an important role in maintaining the planet's climate balance. They carry the moisture evaporated by the oceans to the land, irrigating its surface and providing the possibility of the existence of numerous animals and flora Earth.

Like some other planets solar system The earth is surrounded by a layer of gases. This layer is called the atmosphere. Earth atmosphere consists mainly of nitrogen and oxygen.

Individual gas molecules are constantly high speed moving in different directions. All together they are firmly attached to the Earth, by the force of its gravity.

What is wind?

Wind is the joint movement in one direction of large masses of atmospheric gas molecules. A stream of such molecules moving synchronously can whistle, blowing around a tall building, and tear off hats from passers-by, but if there is a whole river of molecules, and even several kilometers wide, then such a wind can fly around the entire planet.

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Why is there a rainbow?

In a closed room where the air barely moves, you can even forget about its existence. But if you put your hand outside the window of a moving car, it becomes clear that air exists, and although it is invisible, it exerts a noticeable pressure. Indeed, we constantly experience the pressure of air, which seems ephemeral and weightless. But in fact, the entire atmosphere of the Earth weighs no less than 5 quadrillion tons.

Winds happen because the atmospheric pressure in different parts of the atmosphere is somewhat different. Why does pressure difference cause wind? Imagine a dam. The height of the water level on one side is 6 meters, on the other - 3. If the locks of the dam are opened, the water will quickly flow in the direction where the water level is 3 meters, and will continue to flow until the water levels are equal. Something similar happens with air.

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Why does the wind blow from the sea to the land during the day, and vice versa at night?

The pressure in different parts of the atmosphere is different, because these parts have different temperatures. Molecules move faster in warm air and tend to spread apart. different sides, therefore warm air is more rarefied, its weight decreases, and the pressure it creates decreases. In cold air, the molecules gather in tighter clusters, the weight of such air is greater, which means that the pressure is higher than that of warm air.