Determining the strength of the wind by external signs. Wind Force: Measurement and Use

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Wind is the movement of air relative to earth's surface. As you know, the atmosphere is not static, the air in it constantly circulates, moves: it rises and falls.

Differences in the degree of heating of the air contribute to the occurrence of pressure drops in the air masses and set them in motion - air moves from areas of high pressure to areas low pressure. How more difference temperatures between air masses, the stronger the wind.

Wind speed is measured in meters per second, kilometers per hour or points (1 point equals 2 m/s). The average long-term wind speed near the earth's surface is 4-9 m/s, and the maximum average annual wind speed on the coast of Antarctica reaches 22 m/s. Wind speed of 5-8 m/s is considered moderate, above 14 m/s - strong, above 20-25 m/s - storm, above 30-35 m/s - hurricane.

The direction of air movement is determined by the interaction of several forces. These are the Coriolis force (taking into account the influence of the Earth's rotation on moving air), gravity, pressure gradient force and centrifugal force.

Since the cause of wind is pressure differences at different points on the earth's surface, if you stand with your back to the wind in the northern hemisphere, the high pressure area will be on the right, and the low pressure area will be on the left, that is, low pressure is located to the left of the direction of the air flow, and high pressure on the right. In the southern hemisphere, the opposite is true.

The direction of the wind in meteorology is determined by the side of the horizon from which it blows.

HURRICANE ENERGY

The collective name of hurricanes, storms, typhoons is tropical cyclones.

It's gigantic atmospheric vortices with air pressure decreasing towards the center and air circulation around the center counterclockwise in the Northern Hemisphere and clockwise in the Southern.

Wind speeds in deep cyclones with large baric gradients can reach storm and hurricane levels.

They occur in the oceans in tropical latitudes.

The main energy source of the cyclone is the release of heat during the condensation of water vapor.

A comparison of the amount of energy released during the rampant elements and atomic explosions showed that during a typical summer thunderstorm, thirteen times more energy is released than during the explosion of an atomic bomb dropped on Nagasaki.

During a medium-strength hurricane, it is released 500,000 times more.

An atomic explosion on the Bikini Atoll lifted 10 million tons of water into the air, and during a hurricane, 2,500 million tons of rain fell on Puerto Rico in a few hours, i.e. 250 times more.

BREEZES

Why is it quiet on the seashore in summer only early in the morning or in the evening?

This situation occurs quite often, but not always. The reason for this is the fact that water has a higher heat capacity, heats up more slowly and cools down more slowly.

A - Sea breeze (day), B - Coastal breeze (night)

In the early morning hours, when the sun slightly warms the earth, the temperatures of the sea surface and the land are equalized; during the day, the land turns out to be warmer than water, and by the evening, cooling down, it again becomes heated for a while, just like water. When there is no difference in the temperature of water and land, there is no movement of air, the wind subsides, the sea calms down.

During the day, the air that quickly warms up over land rises, and colder air comes to replace it from the sea - a sea breeze blows; at night, the situation changes: the wind blows from land to sea - a coastal breeze.

Pauses are observed in the morning and in the evening - short lulls during periods of change in the direction of the breeze winds. Such an alternation of day and night winds, or the so-called breeze circulation, takes place during the warm season with stable sunny weather and high atmospheric pressure. When a cyclone comes, it brings with it stormy weather and the breezes cease.

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Scale for determining the speed, strength and name of the wind (Beaufort scale)

Wind force in points	Wind speed m/s (km/h)	wind name	Local signs for determining the strength, speed and name of the wind
0-0,2 (0-0,72)	Calm (calm)	Land (C): leaves are still, smoke rises vertically. Sea (M): mirror sea
0,3-1,5 (1,1-5,4)	Quiet	C: the leaves are motionless, the smoke is deflected, the weather vane is motionless. M: ripples, no foam on the ridges.
1,6-3,3 (5,8-11,9)	Easy	C: the leaves rustle, a slight breath is felt on the face, the weather vane moves. M: short waves, crests do not tip over and appear glassy.
3,4-5,4 (12,2-19,4)	Weak	C: light flags and small branches of trees with leaves are waving. M: short, well-defined waves. The combs tip over, form a vitreous foam, occasionally small white lambs form.
5,5-7,9 (19,8-28,4)	Moderate	C: flags flutter, tree branches without leaves sway, dust and papers rise from the ground. M: the waves are elongated, white lambs are visible in many places.
8-10,7 (28,8-38,5)	Fresh	C: Large flags are raised, large, leafy branches, thin trunks sway. M: well developed in length, but not very large waves, white lambs are visible everywhere (splashes form in some cases)
10,8-13,8 (38,9-49,7)	Strong	S: thick tree branches sway, wind sounds are heard in the building, telegraph wires hum, it is difficult to use an umbrella. M: Large waves begin to form. White foamy ridges occupy large areas (splatter is likely).
13,9-17,1 (50-61,6)	Strong	C: tree trunks sway, it is difficult to go against the wind. M: waves pile up, crests break, foam falls in stripes in the wind.
17,2-20,7 (61,9-74,5)	Very strong	C: the wind breaks thin branches and dry branches of trees, it is noticeably difficult to move against the wind. M: moderately high long waves. On the edges of the ridges, spray begins to take off. Stripes of foam lie in rows in the direction of the wind.
20,8-24,4 (74,9-87,8)	Storm	C: the wind breaks branches on trees, rips off light objects, roofs, knocks down fences, slight damage is observed. M: -//-
24,5-28,4 (88,2-102,2)	Heavy storm	C: the wind bends the trees to the ground, weak trees uproots, destruction of buildings is observed. Rarely on dry land. M: very high waves with long downward curved crests. The resulting foam is blown by the wind in large flakes in the form of thick white stripes. The surface of the sea is white with foam. The strong roar of the waves is like blows. Visibility is poor.
28,5-32,6 (102,6-117,4)	Violent storm	C: the wind causes great destruction of buildings over a significant area, uproots trees. It is very rare on land. M: exceptionally high waves. Small to medium sized boats are sometimes out of sight. The sea is all covered with long white flakes of foam, spreading downwind. The edges of the waves are everywhere blown into foam. Visibility is poor.
32.7 (117.7) or more	Hurricane	S: Total destruction. It is very rare on land. M: The air is filled with foam and spray. The sea is all covered with strips of foam. Very poor visibility. How and why does wind speed change, wind force parameters

Distinguish smoothed speed over a short period of time and instant, speed in this moment time. Velocity is measured with an anemometer using a Wild board.

The highest average annual wind speed (22 m/s) was observed on the coast of Antarctica. The average daily speed there sometimes reaches 44 m / s, and at some moments reaches 90 m / s.

The wind speed has a diurnal variation. It is close to the diurnal variation of temperature. Max speed in the surface layer (100 m - in summer, 50 m - in winter) is observed at 13-14 hours, the minimum speed is at night. In higher layers of the atmosphere, the diurnal variation of the velocity is reversed. This is explained by the change in the intensity of vertical exchange in the atmosphere during the day. In the daytime, intense vertical exchange makes it difficult for the horizontal movement of air masses. At night, there is no such obstacle, and Bm move in the direction of the baric gradient.

The wind speed depends on the pressure difference and is directly proportional to it: the greater the pressure difference (horizontal baric gradient), the greater the wind speed. The average long-term wind speed at the earth's surface is 4-9 m/s, rarely more than 15 m/s. In storms and hurricanes (temperate latitudes) - up to 30 m/s, in gusts up to 60 m/s. In tropical hurricanes, wind speeds reach up to 65 m/s, and in gusts they can reach 120 m/s.

Instruments used to measure wind speed are called anemometers. Most anemometers are built on the principle of a windmill. So, for example, the Fuss anemometer has four hemispheres (cups) at the top, facing the same direction (Fig. 75).

This system of hemispheres rotates about a vertical axis, and the number of revolutions is noted by a counter. The device is exposed to the wind, and when the "mill of the hemispheres" acquires more or less constant speed, the counter is turned on for a precisely defined time. According to the plate, which indicates the number of revolutions for each wind speed, and the speed is determined by the number of revolutions found. There are more sophisticated instruments that have a device for automatically recording the direction and speed of the wind. Simple instruments are also used, which can simultaneously determine the direction and strength of the wind. An example of such a device is the Wild weather vane, which is common at all meteorological stations.

The direction of the wind is determined by the side of the horizon from which the wind is blowing. For its designation, eight main directions (rhumbs) are used: N, NW, W, SW, S, SE, B, NE. The direction depends on the pressure distribution and on the deflecting effect of the Earth's rotation.

Rose of Wind. Winds, like other phenomena in the life of the atmosphere, are subject to strong changes. Therefore, here we have to find average values.

To determine the prevailing wind directions for a given period of time, proceed as follows. Eight main directions, or rhumbs, are drawn from some point, and on each, according to a certain scale, the frequency of winds is postponed. In the resulting image, known as wind roses, clearly visible prevailing winds(Fig. 76).

The strength of the wind depends on its speed and shows what dynamic pressure the air flow exerts on any surface. Wind strength is measured in kilograms per square meter (kg/m2).

wind structure. The wind cannot be imagined as a uniform air current having the same direction and the same speed throughout its mass. Observations show that the wind blows gusty, as if in separate shocks, sometimes subsides, then regains its former speed. At the same time, the direction of the wind is also subject to change. Observations made in higher layers of air show that gustiness decreases with height. It is also noted that at different times of the year and even at different hours of the day, the gustiness of the wind is not the same. The greatest impetuousness is observed in the spring. During the day, the greatest weakening of the wind is at night. The gustiness of the wind depends on the nature of the earth's surface: the more irregularities, the greater the gustiness and vice versa.

Causes of winds. The air remains at rest as long as the pressure in a given area of the atmosphere is distributed more or less evenly. But as soon as the pressure in any area increases or decreases, air will flow from the place of greater pressure towards less. The movement of air masses that has begun will continue until the pressure difference is equalized and equilibrium is established.

Stable equilibrium in the atmosphere is almost never observed, and therefore winds are among the most frequently repeated phenomena in nature.

There are many reasons for disturbing the balance of the atmosphere. But one of the first causes of the pressure difference is the temperature difference. Let's consider the simplest case.

Before us is the surface of the sea and the coastal part of the land. During the day, the land surface heats up faster than the sea surface. Due to this, the lower layer of air over land expands more than over the sea (Fig. 77, I). As a result, an air current is immediately created at the top from a warmer area to a colder one (Fig. 77, II).

Due to the fact that part of the air from the warm region has flowed (above) towards the cold one, the pressure within the cold region will increase, and within the warm region it will decrease. As a result, an air current arises now in the lower layer of the atmosphere from the cold to the warm region (in our case, from the sea to land) (Fig. 77, III).

Such air currents usually occur on sea coast or along the shores of large lakes and are called breezes. In our example, the breeze is daytime. At night, the picture is completely opposite, because the surface of the land, cooling faster than the surface of the sea, becomes colder. As a result, in the upper layers of the atmosphere, the air will flow towards the land, and in the lower layers towards the sea (night breeze).

The rise of air from the warm area and the lowering in the cold unites the upper and lower currents and creates a closed circulation (Fig. 78). In these closed circuits, the vertical parts of the path are usually very small, while the horizontal ones, on the contrary, can reach enormous sizes.

Causes of different wind speeds. It goes without saying that the wind speed must depend on the pressure gradient (i.e., be determined primarily by the difference in pressure per unit distance). If, apart from the force due to the gradient, no other forces acted on the mass of air, then the air would move uniformly accelerated. However, this does not work, because there are many reasons that slow down the movement of air. This is primarily friction.

There are two types of friction: 1) the friction of the ground layer of air on the earth's surface and 2) the friction that occurs inside the moving air itself.

The first is directly dependent on the nature of the surface. So, for example, the water surface and the flat steppe create the least friction. Under these conditions, the wind speed always increases significantly. The surface, which has irregularities, creates large obstacles to moving air, which leads to a decrease in wind speed. Urban buildings and forest plantations especially strongly reduce the wind speed (Fig. 79).

Observations made in the forest showed that as early as 50 m from the edge of the wind speed decreases to 60-70% of the original speed, in 100 m up to 7%, in 200 m up to 2-3%.

The friction that occurs between adjacent layers of moving air masses is called internal friction.

Internal friction causes the transfer of motion from one layer to another. The surface layer of air as a result of friction on the earth's surface has the slowest movement. The overlying layer, in contact with the moving lower layer, also slows down its movement, but to a much lesser extent. Even less impact next layer etc. As a result, the speed of air movement gradually increases with height.

Wind direction. If the main cause of wind is pressure difference, then the wind must blow from an area of higher pressure to an area of lower pressure in a direction perpendicular to the isobars. However, this does not happen. In reality (as established by observations) the wind blows mainly along the isobars and only slightly deviates towards low pressure. This is due to the deflecting effect of the Earth's rotation. At one time we have already said that any moving body under the influence of the rotation of the Earth deviates from its original path in the northern hemisphere to the right, and in the southern hemisphere to the left. It was also said that the deviating force in the direction from the equator to the poles increases. It is quite clear that the movement of air, which has arisen due to the difference in pressure, immediately begins to experience the influence of this deflecting force. By itself, this power is small. But due to the continuity of its action, in the end the effect is very large. If there were no friction and other influences, then as a result of a continuously acting deflection, the wind could describe a closed curve close to a circle. In fact, due to the influence of various causes, such a deflection does not occur, but nevertheless it is still very significant. It suffices to indicate at least the trade winds, the direction of which, when the Earth is stationary, should coincide with the direction of the meridian. Meanwhile, their direction in the northern hemisphere is northeast, in the south - southeast, and in temperate latitudes, where the force of deviation is even greater, the wind blowing from south to north acquires a west-southwest direction (in the northern hemisphere).

Major systems of winds. The winds observed on the earth's surface are very diverse. Depending on the causes that give rise to this diversity, we will divide them into three large groups. The first group includes winds, the causes of which depend mainly on local conditions, the second - winds due to the general circulation of the atmosphere, and the third - the winds of cyclones and anticyclones. Let's start our consideration with the simplest winds, the causes of which depend mainly on local conditions. Here we include breezes, various mountain, valley, steppe and desert winds, as well as monsoon winds, which already depend not only on local causes, but also on general circulation atmosphere.

Winds are extremely diverse in origin, nature and significance. Thus, in temperate latitudes, where westerly transport dominates, westerly winds (NW, W, SW) prevail. These areas occupy vast spaces - from about 30 to 60 ° in each hemisphere. In the polar regions, winds blow from the poles towards the zones reduced pressure temperate latitudes. These areas are dominated by northeasterly winds in the Arctic and southeasterly winds in the Antarctic. At the same time, the southeast winds of the Antarctic, in contrast to the Arctic ones, are more stable and have high speeds.

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Signs by which the direction of the wind can be determined in flight are divided into direct and indirect. Direct signs directly indicate the speed and direction of the surface wind. By indirect evidence, one can only assume with some probability that the wind near the earth blows in one direction or another.

Direct indications include:

removal of smoke from fires or chimneys;
flags flying in settlements;
dust drift behind vehicles moving on country roads;
movement of waves and ripples on water bodies.

Rice. 161. Determination of wind direction by smoke, flags and dust.

On small ponds and lakes, the water surface is located below the surrounding land. Therefore, the shores can block the wind. As a result, there will be a calm on the water surface near the leeward shore, and then a strip of ripples expanding towards the windward shore ( see fig. 162).

Rice. 162. Determination of wind direction by ripples on water bodies.

In the absence of direct wind indicators, indirect ones should be used. However, remember: indications of indirect signs do not always correspond to reality.

The simplest indirect sign is the wind speed and direction at the start. If you have just begun to master thermal flights and were able to fly away from the launch site by only 5-10 km, then it is quite acceptable to assume that during your flight, which is no more than 10-15 minutes, the wind could not have had time to change significantly.

What determines the strength and speed of the wind?

In this case, you can well assume that the landing wind will not be much different from the one that blew at the start.

When flying on flat ground, you can also assume that the direction of the wind at altitude is roughly the same as the wind near the ground. You can determine the direction of the wind at a height and approximately estimate its speed by the following features:

the tops of cumulus clouds are shifted relative to their bases in the "downwind" direction;
wind at altitude can be estimated from the movement of cloud shadows;
if you put the paraglider in a gentle spiral, then the direction of the wind will show you the drift of the device.

WARNING
Do not try to use indirect indications of wind direction when flying in the mountains. Due to strong temperature contrasts, the speed and direction of the wind in the mountains change very significantly in heights, gorges and valleys.

Article source: http://firstep.ru/kulp/theory/lection-05-12.php

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 glasses the globe differently, air masses tend to spread over the earth's surface more evenly and fill the place where the atmosphere is not so dense.

Atmospheric pressure itself is the pressure of air on the 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 a high atmospheric pressure to the low area.

The air heats up extremely unevenly, 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 scale with twelve measurements, 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. Its observation time is all year round. On a 12-point scale, this wind blows with a force of 3-4.

Breeze – warm wind with less localization than, for example, a monsoon or a trade wind.

winds. What determines the speed and direction of the 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.

And finally boron- is a sharp wind, characterized by coldness. Its localization is the mountain ranges, from which it blows to the valleys. The wind can develop a fairly high speed (up to 9 points), but has a fickle nature.

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Wind Raz

Alexey Bakaldin

Lenya ran up to his ninth floor. The elevator in the building of the military camp worked, one might say, on holidays, but not for everyone and not every year. But it was a great boost. After all, at sea, submarine officer Leonid Bystrykin is not physically tense, but there are many “seas” (exits to the sea)! And now the boat has returned from a week-long voyage, and the commander released the senior lieutenant in order to prepare for the entry into service, the submarine duty officer.
The door of the apartment was opened by Antonina's wife, beloved Tonechka. And the three-year-old Verunchnik was delighted: “Daddy sat down!” - and hung on her leg.
— Hello, My, good ones! How I missed you! - taking his daughter in his arms and kissing her, the happy father of the family tried to hug Tonya. She somehow strangely pulled away, and on her face there was not a trace of the joy of her husband's return.
“Vera, go finish painting your cat,” said the wife, removing her daughter from her father’s arms, “are you making a gift for dad?”
- Meow! Kittens! - the daughter squealed and disappeared into the room.
- Something happened? - carefully studying the face of his wife, the husband asked, - do you have such a face, as if someone had died again?
The fact is that a month ago, Bystrykin's father died. Leonid had to fly to the funeral, and because of his sick daughter, he traveled alone on this trip. On his return, he went to sea on his ship the next day. About the death telegram loved one said Tonya. It was then that she had such a sad, tense face as she does today.
“Yes!” the answer was not loud. - I fell in love with another person. I cheated on you and I'm leaving you!
There were tears in her eyes. Leonid was taken aback! At some point, it began to seem that this was not reality!
- Wait a minute! Wait a minute! How come? And our family, and the daughter?
"I'll take my daughter with me!"
They went into the kitchen. The news was like a tub cold water! Thoughts fled, it is almost impossible to collect them together.
- Wait a minute! Tonya, Tonya, how are you? We are such a friendly, happy family! We are fine! – in fact it was true. They got married when he was in his fourth year of college. Both friends and parents admired the young couple. In love, a sweet daughter was born! Then there was a move to the place of service, to the North. Getting the long-awaited housing and happiness in a single officer's family!
- I've made up my mind! It's my fault, I'm sorry! - burst his wife, - I fell in love with him more than you and we have already slept. You won't forgive me! I'm leaving! She turned to the window.
— Wait! I have to go on duty now. We must prepare for the intercession. Let's move the conversation to tomorrow, after the shift, okay?
- It will not change anything!
- But still! - Bystrykin left the kitchen, his wife remained standing at the window.
As if in a fog, he began to prepare for duty. The time when it was necessary to arrive for a divorce, to enter the service, was already short, but here it flew at the speed of sound! Lenya went into the room to change, his uniform smelled like a boat. The daughter at the children's table diligently covered her drawing with a pen from her father.
- Draw, draw, baby, I'm not peeping!
He threw off his uniform, took a dressing gown and went to the bath. In the head, like a hammer beats the brain! “Leave! No! What's wrong?!" After a quick shower, he began to shave. Blood rushed to his face. "What to do?" Lenya covered his cheeks with foam. “We need to save the family, I can’t live without my daughter.” He makes a movement with a razor and a cut appears on his face. “I can’t do without Antonina” - a cut on my neck. Having shaved and stopped the blood, Leonid returned to the room. He began to dress in a fresh set of uniforms.
- Dad! Where are you going? The daughter had anxiety in her eyes.
- Bunny! My! I'll be back tomorrow and we'll play again. Here's a present for you. - He pulled out a bar of boat chocolate and handed it to Verunchik. He usually gave chocolate to his wife. And the wife gave it to the child in portions, fearing diathesis.
Today the rule could be broken.

§ 5. Wind. Wind direction and speed. The power of the wind.

- Thank you! - the girl rustled the wrapper.
- Smart girl! Goodbye! - pressing and kissing his daughter, the assembled dad went out into the corridor.

The wife did not leave the kitchen. She did not come out, and when Leonid fully gathered himself, he opened the door and, standing on the threshold, said loudly:
- I'm all gone! Bye!
- Bye! - a child's voice from the daughter's room. The wife was not heard.
Closing the door behind him, the officer quickly began to go downstairs. His face was on fire. All his thoughts were still in the apartment, in his World, which was collapsing!

Before the intercession, it was necessary to run into the boat. Get a service weapon - a pistol with equipment and two clips with cartridges. Bystrykin went to the piers where the boats were moored. As if sensing his mood, the weather began to deteriorate. The sky turned black and the wind blew. "This is not good!" - Lenya had time to think before he went down into the boat. On duty on the ship, his friend, Marat Batyev. Together they came to the fleet on the same boat as lieutenants and were friends!
- ABOUT! Change, creep! - cheerfully welcomed, Marat. After arriving from the sea, he took over on duty and, naturally, wanted to change as quickly as possible in order to also come home. Meet my wife and son. And also take a bath, wash off the boat load like that! Marat in anticipation of this action was in a very good mood.
- Come on trunk! Bystrykin muttered.
- Get out and sign in the magazine. - Marat pointed to the console where she lay
ammunition with prepared weapons and a carefully opened magazine for issuing weapons.
Weapons are always kept in a safe, but before the shift, so as not to delay, they usually always get it for their colleague.
- E! What is it, evil?
- Yes, so! - Checking the weapon, Lenya left the direct answer. His thoughts were far from the service.
Having signed for the weapon, he took the holster and met Marat's gaze.
“Your face is full of cuts and irritation. Why are you so shaved?
- I know!

I was nervous,” Bystrykin replied in a calm voice. - The wife left, changed.
He turned around and began to climb out of the central post along the ladder, to the top.
- How? - Marat was amazed. Their families were friends. And the first moments he could not drive in response to a friend. Believe in what is said. A good mood from the fact that he will change this hour, hand over his weapon, come home ... Stop! Weapon! Marat had cold sweat running down his back. He just gave out a pistol with cartridges to a man whose wife cheated! The hand reached for the shore telephone. You have to report to the commander.

Leonid did not think of shooting anyone. The routine and frequency of duty in the base did their job. He acted like a programmed automaton. Without thinking about divorce, he collected personnel sailors interceding with him, checked their knowledge and arrived at the place of construction. The brigade duty officer conducted a briefing and examination of the interceders. Routine as a whole, as usual. However, also at the divorce, it was noted that the wind is expected to increase, “Wind Two” has already been announced and possibly the announcement of “Wind Raz”. This meant that the navigator and one of the mechanics should already arrive on the boat. This was done so that in the event of a separation of the boat from the pier, the boat would have working navigation equipment and powered power point. If “Wind Raz” is announced, the entire composition of the ship must be in a strong hull.
In the head of the officer, a detached flash flashed: “Bad luck, guys. From the seas and again to the "iron".

Marat did not find a place for himself in the central post. He himself to a friend, in this state, put a pistol in his hands. He reported to the commander. He shortly replied: “Understood!” and hung up. Batiev ordered to report to the top watchman as soon as he saw the approaching shift. When a report was made on "Larch" (communication system):
I see a change!
- Who is leading? Marat asked almost immediately.
- Senior Lieutenant Bystrykin. - answered the top watchman.
- Wow! - Marat caught his breath.
With the arrival of the shift, the routine procedure for handing over the duty began. Leonid did not want to develop the theme of his family relations. All attempts by Marat, he interrupted. Like, none of your business. Leonid tried to get on duty as quickly as possible, stay with his subordinates and completely immerse himself in the duties of a submarine duty officer. The old shift has gone to base! The routine began. Checking the pressure hull for tightness, working off the watch, checking the compartments, filling out magazines. After dinner, the boat was informed that with the worsening weather, "Wind Raz" was announced.

Wind Raz. This is a storm warning. On the roadstead of the Kola flotilla, a cross of four red lights was lit. All personnel must arrive on the ship. All systems are being launched and the personnel should be ready at any moment for the actions prescribed according to the staffing table ..

Somewhere, after 21.00, everyone arrived on the boat, including the commander, captain of the second rank Zaletsky Vladimir Vladimirovich. Leonid reported, according to the form to the commander, about the measures taken. In the meantime, the personnel were stationed in the compartments according to their combat schedules. The officers and midshipmen, cut off from their families in the evening, frowned and scolded the North, for the winds, snowstorms, and cold. And so the rest is small between the "seas", and then at the pier you will have to spend the whole night on the "iron" and it's not a fact that you can get enough sleep. The exit to the service tomorrow half an hour before the flag was raised, no one, by the way, did not cancel! Yes, if "Wind Raz" is cancelled.

After the life of the ship entered the normal mode, the commander called Leonid to his cabin.
- Well, tell me, Lenya.
-What to tell, comrade commander?
-All! You to me, Greens podkilnaya! We need a full-fledged fighter! With a strong back! And not with thoughts about ... Fuck knows what! Zaletsky said sharply.
-Wife cheated, loves and goes to another! - Leonid tried to hold on.
-It's clear! - Cap, reached out to the "Larch" - Central, Senior Lieutenant Batyev, to me!
- There is! - answered central!
- Lenya! - forget it, - the cap put his hand on Leonid's shoulder!
-How? I have a daughter? I love them?
- Lenya! It hurts. You can't fix a broken plate! Remember, you can forgive a lot, but not betrayal. You will no longer have a life. You are a military man, your daughter will stay with her, and you will not do anything! Consider that both your wife and daughter have died for you today.
- No! Tears ran treacherously down her cheeks.
- Allow me!?? - Marat entered the cabin. Leonid turned away, wiping his tears.
- Come in, Batiev! - Vladimir Vladimirovich, took out a canister with an awl (nautical alcohol). His voice was harsh again - Marat! Hear the order!
Meanwhile, the cap filled two bottles of awl.
- The task, you and senior lieutenant Bystrykin, take it, this is the first bottle was in the hands of Marat, - stomp to, Zaletsky nodded towards Lenya, - to his apartment! Today he must get drunk! Take the third, a miner, it's useless, downwind, anyway! - The second bottle was in the hands of Marat.
-Comrade Commander! I'm on duty on the ship! Bystrykin remembered!
-What the hell!? Duty? Cap looked sternly! - carry a magazine and hand over your weapons! The captain of the second rank Zaletsky is on duty! All the same, everyone sit still for a long time! Yes, Bystrykin has a day off tomorrow, not you! - Cap killed Marat's smile with a look. “You tick-like creatures, don’t be late for raising the flag!”

Having taken Kostya, the miner, the company went to Bystrykin's house! Already from afar, it was clear that the light in Leonid's one-room apartment was not on ...

Five years have passed. Antonina filed for divorce and got married. Leonid, went to sea trying to forget himself in the service. Without which, he indulged in all the hard ... Time heals. Lieutenant Commander Bystrykin found his half. The date of the wedding was set, and at the appointed time, a red cross caught fire on the roadstead of the Kola Flotilla. Wind One! Of the guests, there were only Marat and the miner Kostya! True, the occasion was much happier! The family took place and this time very, very strong!

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Each natural phenomenon, which has different degrees of severity, is usually evaluated in accordance with certain criteria. Especially if information about it must be transmitted quickly and accurately. For wind strength, the Beaufort scale has become a single international benchmark.

Developed by the British rear admiral, a native of Ireland, Francis Beaufort (stress falls on the second syllable) in 1806, the system, improved in 1926 by adding information about the equivalence of wind strength in points of its specific speed, allows you to fully and accurately characterize this atmospheric process, while remaining relevant and to this day.

What is wind?

Wind is the movement of air masses parallel to the surface of the planet (horizontally above it). This mechanism is caused by pressure difference. The direction of movement always comes from the higher area.

To describe the wind, it is customary to use the following characteristics:

speed (measured in meters per second, kilometers per hour, knots and points);
wind strength (in points and m.s. - meters per second, the ratio is approximately 1:2);
direction (according to cardinal directions).

The first two parameters are closely related. They can be mutually denoted by each other's units of measurement.

The direction of the wind is determined by the side of the world from where the movement began (from the north - the north wind, etc.). Velocity determines the pressure gradient.

Baric gradient (otherwise - barometric gradient) - change in atmospheric pressure per unit distance along the normal to a surface of equal pressure (isobaric surface) in the direction of decreasing pressure. In meteorology, the horizontal barometric gradient is usually used, that is, its horizontal component (Great Soviet Encyclopedia).

The speed and strength of the wind cannot be separated. A large difference in indicators between atmospheric pressure zones generates a strong and rapid movement of air masses above the earth's surface.

Features of wind measurement

In order to correctly correlate the data of meteorological services with your real position or to make a measurement correctly, you need to know what standard conditions professionals use.

The measurement of the strength and speed of the wind takes place at a height of ten meters on an open flat surface.
The name of the wind direction is given by the cardinal direction from which it blows.

Managers of water transport, as well as lovers of spending time in nature, often purchase anemometers that determine the speed, which is easy to correlate with the wind force in points. There are waterproof models. For convenience, devices of various compactness are produced.

In the Beaufort system, the description of the height of the waves, correlated with a certain force of wind in points, is given for the open sea. It will be much less in shallow water areas and coastal zones.

From personal to global use

Sir Francis Beaufort not only had a high military rank in the navy, but was also a successful practical scientist who held important posts, a hydrographer and cartographer, who brought great benefits to the country and the world. One of the seas in the Arctic Ocean, washing Canada and Alaska, bears his name. An Antarctic island is named after Beaufort.

A convenient system for estimating wind strength in points, available for fairly accurate determination of the severity of the phenomenon "by eye", Francis Beaufort created for his own use in 1805. The scale had a gradation from 0 to 12 points.

In 1838, the system of visual assessment of weather and wind strength in points began to be officially used by the British Navy. In 1874 it was adopted by the international synoptic community.

In the 20th century, several more improvements were made to the Beaufort scale - the ratio of points and a verbal description of the manifestation of the elements with wind speed (1926), and five more divisions were added - gradation points for the strength of hurricanes (USA, 1955).

Criteria for estimating wind strength in Beaufort points

IN modern form The Beaufort scale has several characteristics that allow, in combination, to most accurately correlate a specific atmospheric phenomenon with his scores.

First, it is verbal information. Verbal description of the weather.
Average speed in meters per second, kilometers per hour and knots.
The impact of moving air masses on characteristic objects on land and sea is determined by typical manifestations.

Non-dangerous wind

Safe wind is determined in the range from 0 to 4 points.

Name	Wind speed (m/s)	Wind speed (km/h)	Description	Characteristic
Calm, complete calm (Calm)		less than 1 km/h	Smoke movement - vertically upwards, tree leaves do not move	The surface of the sea is immovable, smooth
Quiet wind (Light Air)			The smoke has a small angle of inclination, the weather vane is motionless	Light ripples without foam. Waves no higher than 10 centimeters
Light Breeze			Feel the breath of the wind on the skin of the face, there is a movement and rustle of leaves, a slight movement of the weather vane	Short low waves (up to 30 centimeters) with a glass-like crest
Weak (Gentle Breeze)			The continuous movement of foliage and thin branches on the trees, the waving of flags	Waves remain short but more noticeable. The ridges begin to tip over and turn into foam. Rare small "lambs" appear. The height of the waves reaches 90 centimeters, but on average does not exceed 60
Moderate (Moderate Breeze)			Dust, small debris begins to rise from the ground	The waves become longer and rise up to one and a half meters. "Lambs" appear often

A wind of 5 points, characterized as "fresh", or fresh breeze, can be called borderline. Its speed ranges from 8 to 10.7 meters per second (29-38 km/h, or 17 to 21 knots). Thin trees sway along with the trunks. Waves rise up to 2.5 (average up to two) meters. Sometimes there are splashes.

Wind that brings trouble

With a wind force of 6 points, strong phenomena begin that can cause damage to health and property.

Points	Name	Wind speed (m/s)	Wind speed (km/h)	Wind speed (sea streaks)	Description	Characteristic
	Strong (Strong Breeze)				The thick branches of the trees sway strongly, the hum of telegraph wires is heard	Formation of large waves, foam crests acquire significant volume, splashing is likely. The average wave height is about three meters, the maximum reaches four
	Strong (Moderate gale)				The trees are swinging whole	Active movement of waves up to 5.5 meters high overlapping each other, dispersion of foam along the line of wind movement
	Very strong (Gale)				Tree branches break from the pressure of the wind, it is difficult to walk against its direction	Waves of significant length and height: average - about 5.5 meters, maximum - 7.5 m. Moderately high long waves. Sprays fly up. Foam falls in stripes, the vector coincides with the direction of the wind
	Storm (Strong gale)				Wind damages buildings, begins to destroy roof tiles	Waves up to ten meters with an average height of up to seven. The streaks of foam become wider. Tilting combs splatter. Reduced visibility

Dangerous force of the wind

Wind force from ten to twelve points is dangerous and is characterized as a strong (storm) and severe storm (violent storm), as well as a hurricane (hurricane).

Wind uproots trees, damages buildings, destroys vegetation, destroys buildings. The waves make a deafening noise from 9 meters and above, long. At sea, they reach a dangerous height even for large ships - from nine meters and above. Foam covers the water surface, visibility is zero or close to such an indicator.

The speed of movement of air masses is from 24.5 meters per second (89 km / h) and reaches from 118 kilometers per hour with a wind force of 12 points. Violent storms and hurricanes (winds of magnitudes 11 and 12) are very rare.

Additional five points to the classical Beaufort scale

Since hurricanes are also not identical to each other in terms of intensity and degree of damage, in 1955 the United States Weather Bureau adopted an addition to the standard Beaufort classification in the form of five scale units. Wind strength from 13 to 17 points inclusive - these are clarifying characteristics for destructive hurricane winds and related phenomena environment.

How to protect yourself when the elements are raging?

If the storm warning of the Ministry of Emergency Situations catches in an open area, it is better to follow the advice and reduce the risk of accidents.

First of all, you should pay attention to warnings every time - there is no guarantee that atmospheric front will come to the area where you are, but you also cannot be sure that he will once again bypass it. All items should be removed or securely fastened, to protect pets.

If a heavy wind catches in a fragile structure - a garden house or other light structures - it is better to close the windows from the air movement side, and if necessary, strengthen them with shutters or boards. On the leeward, on the contrary, slightly open and fix in this position. This will eliminate the danger of an explosive effect from the pressure difference.

It is important to remember that any strong wind can bring unwanted precipitation - in winter it is snowstorms and snowstorms, in summer dust and sand storms are possible. It should also be borne in mind that strong winds can occur even in absolutely clear weather.

Scale for determining the speed, strength and name of the wind (Beaufort scale)

Distinguish smoothed speed over a short period of time and instant, speed at a given time. Velocity is measured with an anemometer using a Wild board.

The highest average annual wind speed (22 m/s) was observed on the coast of Antarctica. The average daily speed there sometimes reaches 44 m / s, and at some moments reaches 90 m / s.

The wind speed has a diurnal variation. It is close to the diurnal variation of temperature. The maximum speed in the surface layer (100 m - in summer, 50 m - in winter) is observed at 13-14 hours, the minimum speed is at night. In higher layers of the atmosphere, the diurnal variation of the velocity is reversed. This is explained by the change in the intensity of vertical exchange in the atmosphere during the day. In the daytime, intense vertical exchange makes it difficult for the horizontal movement of air masses. At night, there is no such obstacle, and Bm move in the direction of the baric gradient.

This system of hemispheres rotates about a vertical axis, and the number of revolutions is noted by a counter. The device is exposed to the wind, and when the "mill of the hemispheres" acquires a more or less constant speed, the counter is turned on for a precisely defined time. According to the plate, which indicates the number of revolutions for each wind speed, and the speed is determined by the number of revolutions found. There are more sophisticated instruments that have a device for automatically recording the direction and speed of the wind. Simple instruments are also used, which can simultaneously determine the direction and strength of the wind. An example of such a device is the Wild weather vane, which is common at all meteorological stations.

Rose of Wind. Winds, like other phenomena in the life of the atmosphere, are subject to strong changes. Therefore, here we have to find average values.

The strength of the wind depends on its speed and shows what dynamic pressure the air flow exerts on any surface. Wind strength is measured in kilograms per square meter (kg/m2).

Stable equilibrium in the atmosphere is almost never observed, and therefore winds are among the most frequently repeated phenomena in nature.

There are many reasons for disturbing the balance of the atmosphere. But one of the first causes of the pressure difference is the temperature difference. Let's consider the simplest case.

Such air currents usually occur on the coast or along the shores of large lakes and are called breezes. In our example, the breeze is daytime. At night, the picture is completely opposite, because the surface of the land, cooling faster than the surface of the sea, becomes colder. As a result, in the upper layers of the atmosphere, the air will flow towards the land, and in the lower layers towards the sea (night breeze).

There are two types of friction: 1) the friction of the ground layer of air on the earth's surface and 2) the friction that occurs inside the moving air itself.

Observations made in the forest showed that as early as 50 m from the edge of the wind speed decreases to 60-70% of the original speed, in 100 m up to 7%, in 200 m up to 2-3%.

The friction that occurs between adjacent layers of moving air masses is called internal friction. Internal friction causes the transfer of motion from one layer to another. The surface layer of air as a result of friction on the earth's surface has the slowest movement. The overlying layer, in contact with the moving lower layer, also slows down its movement, but to a much lesser extent. The next layer is even less affected, and so on. As a result, the speed of air movement gradually increases with height.

Wind direction. If the main cause of wind is pressure difference, then the wind must blow from an area of higher pressure to an area of lower pressure in a direction perpendicular to the isobars. However, this does not happen. In reality (as established by observations) the wind blows mainly along the isobars and only slightly deviates towards low pressure. This is due to the deflecting effect of the Earth's rotation. At one time we have already said that any moving body under the influence of the rotation of the Earth deviates from its original path in the northern hemisphere to the right, and in the southern hemisphere to the left. It was also said that the deviating force in the direction from the equator to the poles increases. It is quite clear that the movement of air, which has arisen due to the difference in pressure, immediately begins to experience the influence of this deflecting force. By itself, this power is small. But due to the continuity of its action, in the end the effect is very large. If there were no friction and other influences, then as a result of a continuously acting deflection, the wind could describe a closed curve close to a circle. In fact, due to the influence of various causes, such a deviation does not occur, but nevertheless it is still very significant. It suffices to indicate at least the trade winds, the direction of which, when the Earth is stationary, should coincide with the direction of the meridian. Meanwhile, their direction in the northern hemisphere is northeast, in the south - southeast, and in temperate latitudes, where the force of deviation is even greater, the wind blowing from south to north acquires a west-southwest direction (in the northern hemisphere).

Winds are extremely diverse in origin, nature and significance. Thus, in temperate latitudes, where westerly transport dominates, westerly winds (NW, W, SW) prevail. These areas occupy vast spaces - from about 30 to 60 ° in each hemisphere. In the polar regions, winds blow from the poles to low pressure zones of temperate latitudes. These areas are dominated by northeasterly winds in the Arctic and southeasterly winds in the Antarctic. At the same time, the southeast winds of the Antarctic, in contrast to the Arctic ones, are more stable and have high speeds.

Wind direction and speed are one of the best indicators of weather changes. There are 16 wind directions (rhumbs), indicated by the cardinal points. The names of these sixteen points, or directions from which the wind blows, are given in the following table:

Designation		Full name of the wind
international	Russian	international	Russian
N	WITH	North	Northern
NNE	CER	Nord-north-east	north northeast
NE	SW	Nord-ost	Northeastern
ENE	UTC	East-north-east	East Northeast
E	IN	Ost	Oriental
ESE	SEW	east-south-east	East Southeast
SE	SE	Zuid-ost	Southeastern
SSE	SSE	South-South-East	south southeastern
S	YU	South	Southern
SSW	SSW	South-South-West	south southwestern
SW	SW	Southwest	Southwestern
WSW	SW	West southwest	West southwestern
W	Z	West	West
WNW	ZSZ	West northwest	West Northwest
NW	NW	northwest	Northwestern
NNW	CVD	Nord-north-west	north northwestern

The wind is named after the part of the horizon from which it blows. Sailors say that the wind "blows into the compass". This expression will make it easier to remember the above table.

In addition to these names, there are also local ones. So, for example, on the coast of the White Sea and in the Murmansk region, local fishermen call the northeast wind "night owl", the south - "summer", the southeast - "lunch", the southwest - "shelovnik", the northwest - " seaside." There are also names of winds on the Black, Caspian Seas and on the Volga. Great importance to determine the weather have local winds that need to be known and taken into account.

To determine the direction of the wind, you need to moisten your index finger and raise it vertically upwards. It will feel cold on the side facing the wind.

The direction of the wind can also be determined by the pennant, smoke and compass. Facing the wind and holding a compass in front of you, the zero division of which is brought under the northern end of the arrow, they put a match or a thin straight stick on its center, pointing it in the direction in which the observer is facing, that is, towards the wind.

Pressing a match or stick in this position to the glass of the compass, you need to look at what division of the scale it falls on. This will be the part of the horizon where the wind blows from.

An indication of the direction of the wind is the landing of birds. They always land against the wind.

Wind speed is measured by the distance (in meters or kilometers) over which the mass of air moves in 1 second. (hours), as well as in points according to the twelve-point Beaufort system. The wind speed is constantly changing, and therefore more often take into account its average value over 10 minutes. The wind speed is determined by special instruments, but it can be determined quite accurately by eye, using the table below.

Determination of wind speed (according to K.V. Pokrovsky):

wind force (in Beaufort points)	Titles winds different strength	Features to evaluate	Speed wind (in m/s)	Speed wind (in km/h)
0	calm	The leaves on the trees do not sway, the smoke from the chimneys rises vertically, the fire from the match does not deviate	0	0
1	quiet	The smoke deviates somewhat, but the wind is not felt by the face	1	3,6
2	easy	The wind is felt in the face, the leaves on the trees sway	2 - 3	5 - 12
3	weak	The wind shakes small branches and shakes the flag	4 - 5	13 - 19
4	moderate	Branches of medium size sway, dust rises	6 - 8	20 - 30
5	fresh	Thin tree trunks and thick branches sway, ripples form on the water	9 - 10	31 - 37
6	strong	Thick tree trunks sway	11 - 13	38 - 48
7	strong	Big trees sway, it's hard to go against the wind	14 - 17	49 - 63
8	very strong	The wind breaks thick trunks	18 - 20	64 - 73
9	storm	The wind demolishes light buildings, knocks down fences	21 - 26	74 - 94
10	heavy storm	Trees uprooted, stronger buildings demolished	27 - 31	95 - 112
11	severe storm	The wind produces great destruction, knocks down telegraph poles, wagons, etc.	32 - 36	115 - 130
12	Hurricane	Hurricane destroys houses, overturns stone walls	Over 36	Over 120

The strength of the waves of the sea (lake) is determined according to the following table (according to A.G. Komovsky):

Points	signs
0	Completely smooth surface
1	Ripples appear, leaving no traces of foam
2	Large ripple. Short waves are formed. the crests of which begin to break. The remaining foam is transparent.
3	The waves are getting longer. White foam (lambs) appears on the surface of the sea. Waves produce a kind of rustle.
4	The waves are noticeably longer. The crests of the waves break with noise. Numerous lambs appear.
5	Water mountains begin to form. The surface of the sea is covered with lambs.
6	A ripple appears. The noise of breaking crests can be heard at some distance. Stripes of foam appear in the direction of the wind.
7	The height and wavelength increase noticeably. The breaking of the ridges resembles the rolls of thunder. White foam forms dense stripes in the direction of the wind.
8	The waves form high mountains with long and strongly overturning crests. The combs roll with a roar and jolts. The sea becomes completely white.
9	The mountains of waves become so high that visible ships are completely out of sight for a while. The rolling of the ridges makes a deafening noise. The wind begins to break the crests of the waves, and water appears in the air.

On April 10, 1996, the highest wind speed on Earth was recorded on Barrow Island in Australia. Then, during tropical cyclone Olivia, the wind accelerated to 408 kilometers per hour. This figure was confirmed by scientists from the World Meteorological Organization. How exactly they figured it out, Cryptus found out.

Usually, meteorologists find out the wind speed using a cup anemometer (another name is a wind meter). This is such a measuring device, on the vertical axis of which cups are fixed - hemispheres that rotate from any, even the lightest, wind. The stronger the wind, the faster the rotation occurs. From the axis of the device there is a transmission to the revolution counter. He determines what the wind speed is now - two, three or four meters per second. To understand the direction, weather vanes are installed next to the anemometers.

Now every person who wants to always be aware of wind speed can buy a digital anemometer. They are inexpensive and cost between 25-35 dollars.

By the way, before people learned to measure wind speed in meters per second, they used the Beaufort scale. This English admiral compiled a table in which the characteristics of different winds were reduced to a system of points - from zero (complete calm) to 12 points (hurricane wind reaching a speed of 117 km / h).

How to measure speed, wind strength and visibility range.

Determining the strength, speed and direction of the wind, visibility range, direction and speed of currents is extremely important when planning and performing dives in the open sea and coastal zone. Fighting the power of nature is pointless and sometimes extremely dangerous, so you should always take into account the influence natural phenomena such as current and wind when planning dives. The information below will help you evaluate the strength of some natural phenomena in order to take them into account when planning your dives.

Wind- this is the movement of an air flow parallel to the earth's surface, resulting from an uneven distribution of heat and atmospheric pressure, and directed from a high pressure zone to a low pressure zone.

The wind is characterized speed (force) And direction. Hmanagement determined by the sides of the horizon and measured in degrees. Wind speed measured in meters per second and kilometers per hour. wind force measured in points.

Beaufort scale - conditional scale for visual determination and recording of wind speed (strength) in points. It was originally developed by the English admiral Francis Beaufort in 1806 to determine the strength of the wind by the nature of its manifestation at sea. Since 1874, it has been accepted for widespread (on land and sea) use in international synoptic practice. In subsequent years, changed and refined. The state of complete calm at sea was taken as zero points. Initially, the system was thirteen-point (0-12). In 1946 the scale was increased to seventeen (0-17). The strength of the wind in the scale is determined by the interaction of the wind with various objects. IN last years wind strength is more often estimated by speed, measured in meters per second at the earth's surface, at a height of about 10 meters above an open, level surface.

Table 1 shows the Beaufort scale, adopted in 1963 by the World Meteorological Organization. The sea wave scale is nine-point (the wave parameters are given for a large sea area, in small areas the wave is less). There are no instruments for measuring the height of the wave, therefore, the sea state in points is determined rather conditionally.

Wind strength in points on the Beaufort scale and sea waves.

Short, well defined waves. The ridges, overturning, form a vitreous foam, occasionally small white lambs are formed. The average wave height is up to 0.6 m, length - 6 m.

The waves are elongated, white lambs are visible in many places. Wave height 1-1.5 m, length up to 15 m.

Well developed in length, but not very large waves, white lambs are visible everywhere (in some cases splashes are formed). Wave height 1.5-2 m, length - 30 m.

Large waves begin to form. White foamy ridges occupy large areas. Water mist is generated. Wave height - 2-3 m, length - 50 m.

Waves pile up, crests break, foam falls in strips in the wind. Wave height up to 3-5 m, length - 70 m.

Moderately high, long waves. On the edges of the ridges, spray begins to take off. Stripes of foam lie in rows in the direction of the wind. Wave height 5-7 m, length - 100 m.

Very high waves with long downward curved crests. The resulting foam is blown by the wind in large flakes in the form of thick white stripes. The surface of the sea is white with foam. The strong roar of the waves is like blows. Visibility is poor. Wave height - 8-11 m, length - 200 m.

Small to medium sized boats are sometimes out of sight. The sea is all covered with long white flakes of foam, which are located in the wind. The edges of the waves are everywhere blown into foam. Visibility is poor. Wave height up to 16 m, length up to 250 m.

The air is filled with foam and spray. The sea is covered with stripes of foam. Very poor visibility. Wave height >16 m, length - 300 m.

Visibility scale.

Visibility- this is the maximum distance at which objects are detected during the day, and navigation lights at night. Visibility is determined by the transparency of the atmosphere, depends on weather conditions and is characterized by the visibility range. Below is a table for determining the visibility range during daylight hours.

Anemometer - a device designed to measure wind speed

A device for measuring wind speed, its strength, as well as determining the direction of its movement in meteorology is called an anemometer. Few today know what it is, because the device has not become widespread, unlike, for example, a barometer, however, it is still used to measure wind parameters both at meteorological stations and in some sports, for example , in sailing.

It is also used in other scientific fields to measure the speed of gases or air, but its most popular use is still as a wind speed meter.

The principle of operation of the device

The principle of operation of most of these devices is as follows: some kind of rotational element is attached to the meter. When the wind blows moving part of the device comes into action and the parameters of the impact on the rotational element are transmitted to the measuring device. This is how mechanical anemometers work, which include two varieties: cup and vane anemometers.

There is also a thermal anemometer based on measuring the temperature shifts of the heating element relative to the initial value under the influence of wind (the higher the speed of air masses, the lower the temperature heating element) and ultrasonic, based on the measurement of shifts in terms of the speed of sound relative to the direction of air masses (if the speed of sound falls relative to its speed in still air, then it moves against the wind, if it grows - downwind).

Types of devices

The principle of operation is to measure the nature of the impact of air masses on special cups fixed on a vertical axis. When there is a breath of wind, the cups rotate around the axis. Meter fixes the number of revolutions around the axis in time and determines the wind speed. The data is transmitted to the wind speed scale, sometimes an electronic meter is used.

The principle of its operation is to measure the nature of the impact of wind on a miniature wheel (impeller), mounted on a vertical axis and protected by a metal ring to protect against mechanical damage. When the wind moves the impeller rotates, which is transmitted to the meter through a system of gear wheels. This device also has two types of meter: manual and electronic.

It is based on a change in the Nusselt number, that is, an increase in the heat loss of a heated body in proportion to an increase in the speed of movement of air masses. This phenomenon can be observed in life - at equal air temperatures in windy weather it becomes colder than in calm weather. This device represents heated to a temperature exceeding the temperature of the environment, a metal wire.

Depending on the current speed, its density and wind humidity, the wire releases a certain amount of energy, which makes it possible to maintain one or another temperature of the wire. The meter records the heat loss and displays the parameters of the wind movement on the screen. However, the device has 2 drawbacks:

Low strength thermal element, since it is represented by a very thin wire.
The error of indication increases over time due to contamination and oxidation of the wire.

In view of the above, they are usually used in aerodynamics in order to measure the parameters of the movement of air masses, because thermal anemometers, unlike mechanical ones, have no inertia, which is a necessary condition for conducting aerodynamic experiments.

The principle of operation lies in the nature of the change in the speed of sound when moving relative to the wind. So it is possible to measure not only the current force of the wind movement, but also the direction of its movement. Since the speed of sound also depends on the temperature of the air, this anemometer is equipped with also a thermometer, according to the readings of which corrections are made to the final results of the parameters of the movement of air masses issued by the anemometer.

To date, the ultrasonic anemometer is the most accurate and modern device of this category. Among other things, some electronic anemometers can also measure the temperature of the air at the time of the movement of air masses, as well as its humidity.

Conclusion

In Russia, multi-purpose devices of this category are also produced, combining the functions various kinds anemometers such as air temperature measurement(thermoanemometer), its humidity (gyrometer), as well as the calculation of the volumetric air flow. Such an anemometer is, for example, a meteometer MES200, difnamometer DMTs01M. These devices are used in the inspection, repair and verification of ventilation in buildings.

All produced on Russian territory are fixed in the state register of measuring instruments and are subject to mandatory verification. Therefore, in Russia there are no anemometers without verification.

Consideration of various types of instruments called anemometer, designed to measure wind speed

Description of anemometers, disclosure of this concept, as well as consideration of various types of anemometers, including Russian ones