What is considered a strong wind. Storms, squalls, hurricanes, their characteristics, damaging factors
The movement of air above the Earth's surface in a horizontal direction is called by the wind. The wind always blows from an area of high pressure to an area of low pressure.
Wind characterized by speed, force and direction.
Wind speed and strength
Wind speed measured in meters per second or points (one point is approximately equal to 2 m/s). The speed depends on the pressure gradient: the greater the pressure gradient, the higher the wind speed.
The strength of the wind depends on the speed (Table 1). The greater the difference between neighboring areas of the earth's surface, the stronger the wind.
Table 1. Wind strength at the earth's surface according to the Beaufort scale (at a standard height of 10 m above an open, flat surface)
Beaufort points |
Verbal definition of wind force |
Wind speed, m/s |
Wind action |
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Calm. Smoke rises vertically |
Mirror smooth sea |
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The direction of the wind is noticeable from the direction of the smoke, but not from the weather vane |
Ripples, no foam on the ridges |
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The movement of the wind is felt on the face, the leaves rustle, the weather vane moves |
Short waves, crests do not capsize and appear glassy |
The leaves and thin branches of the trees sway all the time, the wind flutters the upper flags |
Short, well defined waves. The ridges, overturning, form a glassy foam, occasionally small white lambs are formed |
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Moderate |
The wind raises dust and pieces of paper and moves thin tree branches. |
The waves are elongated, white caps are visible in many places |
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Thin tree trunks sway, waves with crests appear on the water |
Well developed in length, but not very large waves, white caps are visible everywhere (in some cases splashes are formed) |
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Thick tree branches sway, telegraph wires hum |
Large waves begin to form. White foamy ridges occupy significant areas (splashes are likely) |
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The tree trunks are swaying, it’s difficult to walk against the wind |
The waves pile up, the crests break off, the foam lies in stripes in the wind |
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Very strong |
The wind breaks tree branches, it is very difficult to walk against the wind |
Moderately high long waves. Spray begins to fly up along the edges of the ridges. Strips of foam lie in rows in the direction of the wind |
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Minor damage; the wind tears off smoke hoods and tiles |
High waves. The foam falls in wide dense stripes in the wind. The crests of the waves begin to capsize and crumble into spray, which impairs visibility |
Heavy storm |
Significant destruction of buildings, trees are uprooted. Rarely happens on land |
Very high waves with long, downward-curving crests. The resulting foam is blown away 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 |
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Fierce Storm |
Large destruction over a large area. Very rarely observed on land |
Exceptionally high waves. Small and medium-sized vessels are sometimes hidden from view. The sea is all covered with long white flakes of foam, located downwind. The edges of the waves are blown into foam everywhere. Visibility is poor |
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32.7 or more |
The air is filled with foam and spray. The sea is all covered with stripes of foam. Very poor visibility |
Beaufort scale— a conventional scale for visually assessing the strength (speed) of the wind in points based on its effect on ground objects or on sea waves. It was developed by the English admiral F. Beaufort in 1806 and at first was used only by him. In 1874, the Standing Committee of the First Meteorological Congress adopted the Beaufort scale for use in International Synoptic Practice. In subsequent years, the scale was changed and refined. The Beaufort scale is widely used in maritime navigation.
Direction of the wind
Direction of the wind is determined by the side of the horizon from which it blows, for example, the wind blowing from the south is south. The direction of the wind depends on the pressure distribution and the deflecting effect of the Earth's rotation.
On the climate map, the prevailing winds are shown by arrows (Fig. 1). The winds observed at the earth's surface are very diverse.
You already know that the surface of land and water heats up differently. On a summer day, the land surface heats up more. When heated, the air over land expands and becomes lighter. At this time, the air above the reservoir is colder and, therefore, heavier. If the body of water is relatively large, on a quiet hot summer day on the shore you can feel a light breeze blowing from the water, above which it is higher than above the land. Such a light breeze is called a daytime breeze breeze(from the French brise - light wind) (Fig. 2, a). The night breeze (Fig. 2, b), on the contrary, blows from land, since the water cools much more slowly and the air above it is warmer. Breezes can also occur at the edge of the forest. The breeze diagram is shown in Fig. 3.
Rice. 1. Distribution diagram of the prevailing winds on the globe
Local winds can occur not only on the coast, but also in the mountains.
Föhn- a warm and dry wind blowing from the mountains to the valley.
Bora- a gusty, cold and strong wind that appears when cold air passes over low ridges to the warm sea.
Monsoon
If the breeze changes direction twice a day - day and night, then seasonal winds - monsoons- change their direction twice a year (Fig. 4). In summer, the land quickly warms up, and the air pressure above its surface increases. At this time, cooler air begins to move inland. In winter, the opposite is true, so the monsoon blows from land to sea. With the change from the winter monsoon to the summer monsoon, there is a change from dry, partly cloudy weather to rainy.
The effect of monsoons is strongly manifested in the eastern parts of the continents, where they are adjacent to vast expanses of oceans, so such winds often bring heavy precipitation to the continents.
The unequal nature of atmospheric circulation in different regions of the globe determines differences in the causes and nature of monsoons. As a result, a distinction is made between extratropical and tropical monsoons.
Rice. 2. Breeze: a - daytime; b - night
Rice. 3. Breeze pattern: a - during the day; b - at night
Rice. 4. Monsoons: a - in summer; b - in winter
Extratropical monsoons - monsoons of temperate and polar latitudes. They are formed as a result of seasonal pressure fluctuations over the sea and land. The most typical zone of their distribution is the Far East, Northeast China, Korea, and, to a lesser extent, Japan and the northeastern coast of Eurasia.
Tropical monsoons - monsoons of tropical latitudes. They are caused by seasonal differences in heating and cooling of the Northern and Southern Hemispheres. As a result, pressure zones shift seasonally relative to the equator to the hemisphere in which it is summer at a given time. Tropical monsoons are most typical and persistent in the northern Indian Ocean basin. This is greatly facilitated by the seasonal change in atmospheric pressure over the Asian continent. The fundamental features of the climate of this region are associated with the South Asian monsoons.
The formation of tropical monsoons in other areas of the globe occurs less characteristically, when one of them is more clearly expressed - the winter or summer monsoon. Such monsoons are observed in Tropical Africa, northern Australia and the equatorial regions of South America.
Constant winds of the Earth - trade winds And westerly winds- depend on the position of the atmospheric pressure belts. Since low pressure prevails in the equatorial belt, and near 30° N. w. and Yu. w. - high, at the surface of the Earth throughout the year the winds blow from the thirties latitudes to the equator. These are trade winds. Under the influence of the Earth's rotation around its axis, trade winds deviate to the west in the Northern Hemisphere and blow from northeast to southwest, and in the Southern Hemisphere they are directed from southeast to northwest.
From high pressure belts (25-30° N and S latitude), winds blow not only towards the equator, but also towards the poles, since at 65° N. w. and Yu. w. low pressure prevails. However, due to the rotation of the Earth, they gradually deviate to the east and create air currents moving from west to east. Therefore, in temperate latitudes, westerly winds predominate.
In 1963, the World Meteorological Organization clarified Beaufort scale and it was adopted to approximate the speed of wind from its effect on objects on land or from waves on the open sea. Average wind speed is indicated at a standard height of 10 meters above an open, level surface.
The smoke (from the captain's pipe) rises vertically, the leaves of the trees are motionless. Mirror smooth sea.
Wind 0 - 0.2m/s
The smoke deviates from the vertical direction, there are slight ripples in the sea, there is no foam on the ridges. Wave height up to 0.1 m.
You can feel the wind on your face, the leaves rustle, the weather vane begins to move, and there are short waves at sea with a maximum height of up to 0.3 m.
Wind 1.6 - 3.3 m/s.
The leaves and thin branches of the trees are swaying, light flags are swaying, there is a slight disturbance on the water, and occasionally small whitecaps form.
Average wave height 0.6 m. Wind 3.4 - 5.4 m/s.
The wind raises dust and pieces of paper; Thin tree branches are swaying, whitecaps on the sea are visible in many places.
Maximum wave height up to 1.5 m. Wind 5.5 - 7.9 m/s.
Branches and thin tree trunks sway, you can feel the wind with your hand, white lambs are visible everywhere.
Maximum wave height 2.5 m, average - 2 m. Wind 8.0 - 10.7 m/s.
In such weather we tried to leave Darlowo across the Baltic Sea. (Poland) against the wave. In 30 minutes only approx. 10km. and got very wet from the splashes. We were returning along the way - very good. funny.
Thick tree branches sway, thin trees bend, telephone wires hum, umbrellas are difficult to use; white foamy ridges occupy large areas, and water dust is formed. The maximum wave height is up to 4m, the average is 3m. Wind 10.8 - 13.8 m/s.
We encountered this kind of weather on boats in front of Rostock. The navigator was afraid to look around, the most valuable things were stuffed into his pockets, the walkie-talkie was tied to his vest. The splashes from the side waves constantly covered us. For a vodka-motor fleet, not to mention a simple motorboat, this is probably the maximum...
Tree trunks sway, large branches bend, it is difficult to walk against the wind, wave crests are torn off by the wind. The maximum wave height is up to 5.5 m. wind 13.9 - 17.1 m/s.
Thin and dry branches of trees break, it is impossible to speak in the wind, it is very difficult to walk against the wind. Strong seas.
Maximum wave height is up to 7.5 m, average - 5.5 m. Wind 17.2 - 20.7 m/s.
Large trees are bending, the wind is tearing tiles off the roofs, very rough seas, high waves. It is observed very rarely. Accompanied by destruction over large areas. The sea has exceptionally high waves (maximum height - up to 16m, average - 11.5m), small vessels are sometimes hidden from view.
Wind 28.5 - 32.6 m/s. Fierce storm.
The sea is all covered with stripes of foam. The air is filled with foam and spray. Visibility is very poor. Complete p...ts for small vessels, yachts and other ships - it’s better not to hit them.
Wind 32.7 m/s or more...
Wind- this is horizontal movement (air flow parallel to the earth's surface), resulting from uneven distribution of heat and atmospheric pressure and directed from a high pressure zone to a low pressure zone
Wind is characterized by speed (strength) and direction. Direction is determined by the sides of the horizon from which it blows, and is measured in degrees. Wind speed measured in meters per second and kilometers per hour. Wind strength is measured in points.
Wind in boots, m/s, km/h
Beaufort scale- a conventional scale for visual assessment and recording of wind force (speed) in points. Initially, it was 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, this classification has been adopted for widespread (on land and at sea) use in international synoptic practice. In subsequent years it changed and was refined (Table 2). A state of complete calm at sea was taken as zero points. Initially, the system was thirteen-point (0-12 bft, on the Beaufort scale). In 1946 the scale was increased to seventeen (0-17). The strength of the wind on the scale is determined by the interaction of the wind with various objects. In recent years, wind strength is more often assessed by speed, measured in meters per second - at the earth's surface, at a height of about 10m above an open, flat surface.
The table shows the Beaufort scale, adopted in 1963 by the World Meteorological Organization. The sea wave scale is nine-point (parameters are given for a large sea area; in small water areas the waves are less).
Descriptions of the effects of the movement of air masses are given “for the conditions of the earth’s atmosphere near the earth’s or water surface,” with an air density of about 1.2 kg/m3 and above-zero temperatures. On the planet Mars, for example, the ratios will be different.
Wind strength in Beaufort scale and sea waves
Table 1 | Points | Wind speed, m/s | Verbal indication of wind force | Wind action |
|
Wind speed km/h |
on the land |
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0 | at sea (points, waves, characteristics, height and wavelength) | 0-0,2 | Calm | Less than 1 | Complete absence of wind. The smoke rises vertically, the leaves of the trees are motionless.
0. No excitement |
1 | Mirror smooth sea | 0,3-1,5 | 2-5 | Quiet | The smoke deviates slightly from the vertical direction, the leaves of the trees are motionless
1. Weak excitement. |
2 | There are light ripples on the sea, no foam on the ridges. Wave height is 0.1 m, length - 0.3 m. | 1,6-3,3 | 6-11 | Easy | You can feel the wind on your face, the leaves rustle faintly at times, the weather vane begins to move,
2. Low excitement |
3 | The ridges do not tip over and appear glassy. At sea, short waves are 0.3 m high and 1-2 m long. | 3,4-5,4 | 12-19 | Weak | Leaves and thin branches of trees with foliage continuously sway, light flags sway. The smoke seems to be licked from the top of the pipe (at a speed of more than 4 m/sec).
3. Slight excitement |
4 | Short, well defined waves. The ridges, overturning, form a glassy foam, and occasionally small white lambs are formed. The average wave height is 0.6-1 m, length - 6 m. | 5,5-7,9 | 20-28 | The wind raises dust and pieces of paper. Thin branches of trees sway without leaves. The smoke mixes in the air, losing its shape. This is the best wind for operating a conventional wind generator (with a wind wheel diameter of 3-6 m) | 4.Moderate excitement
The waves are elongated, white caps are visible in many places. Wave height is 1-1.5 m, length - 15 m. Sufficient wind thrust for windsurfing (on a board under sail), with the ability to enter planing mode (with a wind of at least 6-7 m/s) |
5 | Fresh | 8,0-10,7 | 29-38 | Branches and thin tree trunks sway, the wind can be felt by hand. Pulls out big flags. Whistling in my ears. | 4. Rough seas
The waves are well developed in length, but not very large; white caps are visible everywhere (in some cases, splashes form). Wave height 1.5-2 m, length - 30 m |
6 | Strong | 10,8-13,8 | 39-49 | Thick tree branches sway, thin trees bend, telegraph wires hum, umbrellas are difficult to use | 5. Major disturbance
Large waves begin to form. White foamy ridges occupy large areas. Water dust is formed. Wave height - 2-3 m, length - 50 m |
7 | Strong | 13,9-17,1 | 50-61 | Tree trunks sway, large branches bend, it is difficult to walk against the wind. | 6. Strong excitement
The waves pile up, the crests break off, the foam lies in stripes in the wind. Wave height up to 3-5 m, length - 70 m |
8 | Very strong |
17,2-20,7 | 62-74 | Thin and dry branches of trees break, it is impossible to speak in the wind, it is very difficult to walk against the wind. | 7. Very strong excitement
Moderately high, long waves. Spray begins to fly up along the edges of the ridges. Strips of foam lie in rows in the direction of the wind. Wave height 5-7 m, length - 100 m |
9 | Storm | 20,8-24,4 | 75-88 | Big trees bend, big branches break. The wind tears tiles off the roofs | 8.Very strong excitement
High waves. The foam falls in wide dense stripes in the wind. The crests of the waves begin to capsize and crumble into spray, which impairs visibility. Wave height - 7-8 m, length - 150 m |
10 | Strong storm |
24,5-28,4 | 89-102 | Rarely happens on land. Significant destruction of buildings, wind knocks down trees and uproots them | 8.Very strong excitement
Very high waves with long, downward-curving crests. The resulting foam is blown away 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. Height - 8-11 m, length - 200 m |
11 | Cruel storm |
28,5-32,6 | 103-117 | It is observed very rarely. Accompanied by great destruction over large areas. | 9. Exceptionally high waves.
Small and medium-sized vessels are sometimes hidden from view. The sea is all covered with long white flakes of foam, located downwind. The edges of the waves are blown into foam everywhere. Visibility is poor. Height - 11m, length 250m |
12 | Hurricane | >32,6 | More than 117 | Devastating destruction. Individual wind gusts reach speeds of 50-60 m.s. A hurricane may occur before a severe thunderstorm | 9. Exceptional excitement
The air is filled with foam and spray. The sea is all covered with stripes of foam. Very poor visibility. Wave height >11m, length - 300m. |
To make it easier to remember(compiled by: website author)
3 - Weak - 5 m/s (~20 km/h) - leaves and thin tree branches sway continuously
5 - Fresh - 10 m/s (~35 km/h) - pulls out large flags, whistles in ears
7 - Strong - 15 m/s (~55 km/h) - telegraph wires are humming, it is difficult to go against the wind
9 - Storm - 25 m/s (90 km/h) - wind knocks down trees, destroys buildings
* The length of the wind wave on the surface of water bodies (rivers, seas, etc.) is the shortest horizontal distance between the tops of adjacent ridges.
Dictionary:
Breeze– weak onshore wind, with force up to 4 points.
Normal wind- acceptable, optimal for something. For example, for sport windsurfing, you need sufficient wind thrust (at least 6-7 meters per second), and for parachute jumping, on the contrary, it is better to have calm weather (excluding lateral drift, strong gusts near the earth's surface and dragging of the canopy after landing).
Storm is called a long-lasting and stormy wind to a hurricane, with a force greater than 9 points (gradation on the Beaufort scale), accompanied by destruction on land and strong waves at sea (storm). Storms are: 1) squalls; 2) dusty (sandy); 3) dust-free; 4) snowy. Squalls begin suddenly and end just as quickly. Their actions are characterized by enormous destructive power (such wind destroys buildings and uproots trees). These storms are possible everywhere in the European part of Russia, both at sea and on land. In Russia, the northern border of the distribution of dust storms passes through Saratov, Samara, Ufa, Orenburg and the Altai mountains. Snow storms of great force occur on the plains of the European part and in the steppe part of Siberia. Storms are usually caused by the passage of an active atmospheric front, deep cyclone or tornado.
Squall- a strong and sharp gust of wind (Peak gusts) with a speed of 12 m/sec and above, usually accompanied by a thunderstorm. At a speed of more than 18-20 meters per second, gusty wind demolishes poorly secured structures, signs, and can break billboards and tree branches, cause power lines to break, which creates a danger for people and cars nearby. Gusty, squally wind occurs during the passage of an atmospheric front and with a rapid change in pressure in the baric system.
Vortex– an atmospheric formation with rotational movement of air around a vertical or inclined axis.
Hurricane(typhoon) is a wind of destructive force and considerable duration, the speed of which exceeds 120 km/h. A hurricane “lives,” that is, moves, usually for 9–12 days. Forecasters give it a name. The hurricane destroys buildings, uproots trees, demolishes light structures, breaks wires, and damages bridges and roads. Its destructive power can be compared to an earthquake. The homeland of hurricanes is the ocean, closer to the equator. Cyclones saturated with water vapor move from here to the west, more and more twisting and increasing speed. The diameters of these giant vortices are several hundred kilometers. Hurricanes are most active in August and September.
In Russia, hurricanes most often occur in the Primorsky and Khabarovsk territories, Sakhalin, Kamchatka, Chukotka, and the Kuril Islands.
Tornadoes– these are vertical vortices; squalls are often horizontal, part of the structure of cyclones.
The word "smerch" is Russian, and comes from the semantic concept of "twilight", that is, a gloomy, stormy situation. A tornado is a giant rotating funnel, inside of which there is low pressure, and any objects that are in the path of the tornado's movement are sucked into this funnel. As he approaches, a deafening roar is heard. A tornado moves above the ground at an average speed of 50–60 km/h. Tornadoes are short-lived. Some of them “live” for seconds or minutes, and only a few - up to half an hour.
On the North American continent, a tornado is called tornado, and in Europe – thrombus. A tornado can lift a car into the air, uproot trees, bend a bridge, and destroy the upper floors of buildings.
The tornado in Bangladesh, observed in 1989, was included in the Guinness Book of Records as the most terrible and destructive in the entire history of observations. Despite the fact that residents of the city of Shaturia were warned in advance about the approach of the tornado, 1,300 people became its victims.
In Russia, tornadoes occur more often in the summer months in the Urals, the Black Sea coast, the Volga region and Siberia.
Forecasters classify hurricanes, storms and tornadoes as emergency events with a moderate speed of spread, so most often it is possible to issue a storm warning in time. It can be transmitted through civil defense channels: after the sound of sirens " Attention everyone!"You need to listen to local television and radio reports.
Symbols on weather maps for wind-related weather events
In meteorology and hydrometeorology, the direction of the wind (“from where it blows”) is indicated on the map as an arrow, the type of plumage of which shows the average speed of air flow. In air navigation, the name of the direction is the opposite. In navigation on water, the unit of speed (knot) of a ship is taken to be equal to one nautical mile per hour (ten knots corresponds to approximately five meters per second).
On a weather map, a long feather of a wind arrow means 5 m/s, a short one - 2.5 m/s, in the shape of a triangular flag - 25 m/s (follows a combination of four long lines and 1 short one). In the example shown in the figure, there is a wind of 7-8 m/s. If the wind direction is unstable, a cross is placed at the end of the arrow.
The picture shows the symbols of wind direction and speed used on weather maps, as well as an example of applying icons and fragments from a hundred-cell matrix of weather symbols (for example, drifting snow and a blowing snow, when previously fallen snow rises and is redistributed in the ground layer of air).
These symbols can be seen on the synoptic map of the Hydrometeorological Center of Russia (http://meteoinfo.ru), compiled as a result of analysis of current data on the territory of Europe and Asia, which schematically shows the boundaries of zones of warm and cold atmospheric fronts and the directions of their movements along the earth's surface.
What to do if there is a storm warning?
1. Close and secure all doors and windows tightly. Apply strips of plaster crosswise to the glass (to prevent fragments from scattering).
2. Prepare a supply of water and food, medicine, a flashlight, candles, a kerosene lamp, a battery-powered receiver, documents and money.
3. Turn off gas and electricity.
4. Remove items from balconies (yards) that could be blown away by the wind.
5. Move from light buildings to stronger ones or civil defense shelters.
6. In a village house, move to the most spacious and durable part of it, and best of all, to the basement.
8. If you have a car, try to drive as far as possible from the epicenter of the hurricane.
Children from kindergartens and schools must be sent home in advance. If a storm warning arrives too late, children should be placed in basements or central areas of buildings.
It is best to wait out a hurricane, tornado or storm in a shelter, a previously prepared shelter, or at least in a basement. However, often, a storm warning is given only a few minutes before the storm arrives, and during this time it is not always possible to get to shelter.
If you find yourself outside during a hurricane
2. You must not be on bridges, overpasses, overpasses, or in places where flammable and toxic substances are stored.
3. Hide under a bridge, reinforced concrete canopy, in a basement, cellar. You can lie down in a hole or any depression. Protect your eyes, mouth and nose from sand and soil.
4. You cannot climb onto the roof and hide in the attic.
5. If you are driving a car on the plain, stop, but do not leave the car. Close its doors and windows tightly. During a snow storm, cover the radiator side of the engine with something. If the wind is not strong, you can shovel the snow from your car from time to time to avoid being buried under a thick layer of snow.
6. If you are in public transport, leave it immediately and seek shelter.
7. If the elements catch you in an elevated or open place, run (crawl) towards some kind of shelter (rocks, forest) that could dampen the force of the wind, but beware of falling branches and trees.
8. When the wind has died down, do not immediately leave the shelter, as the squall may recur in a few minutes.
9. Stay calm and don’t panic, help the victims.
How to behave after natural disasters
1. When leaving the shelter, look around to see if there are any overhanging objects, parts of structures, or broken wires.
2. Do not light gas or fire, do not turn on electricity until special services check the condition of communications.
3. Don't use the elevator.
4. Do not enter damaged buildings or go near downed electrical wires.
5. The adult population assists the rescuers.
Devices
The exact wind speed is determined using a device - an anemometer. If such a device does not exist, you can make a homemade wind measuring “Wild board” (Fig. 1), with sufficient measurement accuracy for wind speeds of up to ten meters per second.
Rice. 1. Homemade wind vane board Wilda:
1 - vertical tube (600 mm long) with a welded pointed upper end, 2 - front horizontal rod of the weather vane with a counterweight ball; 3 - weather vane impeller; 4 - upper frame; 5 - horizontal axis of the board hinge; 6 - wind measuring board (weighing 200 g). 7 - lower fixed vertical rod with cardinal directions mounted on it, in eight directions: N - north, S - south, 3 - west, E - east, NW - northwest, NE - northeast, SE - southeast, SW - southwest; No. 1 - No. 8 - wind speed indicator pins.
The weather vane is installed at a height of 6 - 12 meters, above an open, flat surface. Under the weather vane there are arrows indicating the direction of the wind. Above the weather vane, to tube 1 on the horizontal axis 5, a wind measuring board 6 measuring 300x150 mm is hinged to frame 4. Board weight - 200 grams (adjusted using a reference device). Moving back from frame 4 is a segment of an arc attached to it (with a radius of 160 mm) with eight pins, of which four are long (140 mm each) and four are short (100 mm each). The angles at which they are fixed are with the vertical for pin No. 1-0°; No. 2 - 4°; No. 3 - 15.5°; No. 4 - 31°; No. 5 - 45.5°; No. 6 - 58°; No. 7 - 72°; No. 8-80.5°.
Wind speed is determined by measuring the angle of deflection of the board. Having determined the position of the wind measuring board between the pins of the arc, turn to the table. 1, where this position corresponds to a certain wind speed.
The position of the board between the pegs gives only a rough idea of the wind speed, especially since the wind strength changes quickly and frequently. The board never remains in any one position for long, but constantly fluctuates within certain limits. By observing the changing slope of this board for 1 minute, its average slope is determined (calculated by averaging the maximum values) and only after that the average minute wind speed is judged. For high wind speeds exceeding 12-15 m/sec, the readings of this device have low accuracy (this limitation is the main drawback of the considered scheme)....
Application
Average wind speed on the Beaufort scale in different years of its use
table 2
Point | Verbal characteristic |
Average wind speed (m/s) according to recommendations | ||||
Simpson | Köppen | International Meteorological Committee | ||||
1906 | 1913 | 1939 | 1946 | 1963 | ||
0 | Calm | 0 | 0 | 0 | 0 | 0 |
1 | Quiet wind | 0,8 | 0,7 | 1,2 | 0,8 | 0,9 |
2 | Light breeze | 2,4 | 3,1 | 2,6 | 2,5 | 2,4 |
3 | Light wind | 4,3 | 4,8 | 4,3 | 4,4 | 4,4 |
4 | Moderate wind | 6,7 | 6,7 | 6,3 | 6,7 | 6,7 |
5 | Fresh breeze | 9,4 | 8,8 | 8,7 | 9,4 | 9,3 |
6 | Strong wind | 12,3 | 10,8 | 11,3 | 12,3 | 12,3 |
7 | strong wind | 15,5 | 12,7 | 13,9 | 15,5 | 15,5 |
8 | Very strong wind | 18,9 | 15,4 | 16,8 | 18,9 | 18,9 |
9 | Storm | 22,6 | 18,0 | 19,9 | 22,6 | 22,6 |
10 | Heavy storm | 26,4 | 21,0 | 23,4 | 26,4 | 26,4 |
11 | Fierce Storm | 30,0 | 27,1 | 30,6 | 30,5 | |
12 | Hurricane | 29,0 | 33,0 | 32,7 | ||
13 | 39,0 | |||||
14 | 44,0 | |||||
15 | 49,0 | |||||
16 | 54,0 | |||||
17 | 59,0 |
The Hurricane Scale was developed by Herbert Saffir and Robert Simpson in the early 1920s to measure the potential damage of a hurricane. It is based on numerical values of maximum wind speed and includes an assessment of storm surges in each of five categories. In Asian countries, this natural phenomenon is called a typhoon (translated from Chinese as “great wind”), and in North and South America it is called a hurricane. When quantifying wind flow speed, the following abbreviations are used: km/h / mph- kilometers / miles per hour, m/s- meters per second.
table 3
№ | Category | Maximum wind speed | Storm waves, m | Effect on ground objects | Effect on the coastal zone |
1 | Minimum | 119-153 km/h 74-95mph 33-42 m/s |
12-15 | Trees and bushes damaged | Minor damage to the piers, some small vessels in the anchorage were torn from their anchors |
2 | Moderate | 154-177 km/h 96-110mph 43-49 m/s |
18-23 | Significant damage to trees and bushes; some trees were downed, prefabricated houses were badly damaged | Significant damage to piers and marinas, with small vessels at anchor torn from their anchors |
3 | Significant | 178-209 km/h 111-129 mph 49-58 m/s |
27-36 | Large trees were downed, prefabricated houses were destroyed, and some small buildings had windows, doors and roofs damaged. | Severe flooding along the coastline; small buildings on the shore were destroyed |
4 | Huge | 210-249 km/h 130-156 mph 58-69 m/s |
39-55 | Trees, bushes and billboards were toppled, prefabricated houses were destroyed to the ground, windows, doors and roofs were badly damaged | Areas located at an altitude of up to 3 meters above sea level are flooded; floods extend 10 km inland; damage from waves and debris carried by them |
5 | Catastrophe | >250 km/h >157 mph > 69 m/s |
More than 55 | All trees, bushes and billboards have been knocked down and many buildings have been seriously damaged; some buildings were completely destroyed; prefabricated houses demolished | Severe damage was caused to the lower floors of buildings up to 4.6 meters above sea level in an area extending 457 meters inland. Mass evacuations of the population from coastal areas are necessary |
Tornado scale
The tornado scale (Fujita-Pearson scale) was developed by Theodore Fujita to classify tornadoes by the degree of wind damage caused. Tornadoes are characteristic mainly of North America.
table 4
Category | Speed, km/h | Damage |
F0 | 64-116 | Destroys chimneys, damages tree crowns |
F1 | 117-180 | Tears prefabricated (panel) houses from the foundation or overturns them |
F2 | 181-253 | Significant destruction. Prefabricated houses are destroyed, trees are uprooted |
F3 | 254-332 | Destroys roofs and walls, scatters cars, overturns trucks |
F4 | 333-419 | Destroys fortified walls |
F5 | 420-512 | Lifts houses and moves them a considerable distance |
Glossary of terms:
Leeward side object (protected from the wind by the object itself; an area of high pressure, due to strong deceleration of the flow) faces where the wind is blowing. In the picture - on the right. For example, on the water, small ships approach larger ships from their leeward side (where they are protected from waves and wind by the larger ship's hull). “Smoking” factories and enterprises should be located in relation to residential urban areas - on the leeward side (in the direction of the prevailing winds) and separated from these areas by sufficiently wide sanitary protection zones.
Windward side object (hill, sea vessel) - on the side from which the wind blows. On the windward side of the ridges, upward movements of air masses occur, and on the leeward side, a downward airfall occurs. The greatest part of precipitation (in the form of rain and snow), caused by the barrier effect of the mountains, falls on their windward side, and on the leeward side the collapse of colder and drier air begins.
In meteorology, when indicating the direction of the wind, the circle is divided into sixteen parts, according to 16-ray rose of rhumbs(after 22.5 degrees). For example, north-northeast is designated as NNE (the first letter is the main direction to which the bearing is closer). Four main directions: North, East, South, West.
Approximate calculation of dynamic wind pressure per square meter of advertising board (perpendicular to the plane of the structure) installed near the roadway. In the example, the maximum storm wind speed expected in a given location is assumed to be 25 meters per second.
Calculations are carried out according to the formula:
P = 1/2 * (air density) * V^2 = 1/2 * 1.2 kg/m3 * 25^2 m/s = 375 N/m2 ~ 38 kilograms per square meter (kgf)
Notice that the pressure increases as the square of the speed. Take into account and include in the construction project sufficient margin of safety, stability (depending on the height of the support stand) and resistance to strong gusts of wind and precipitation, in the form of snow and rain.
At what wind strength are civil aviation flights canceled?
The reason for disruption of flight schedules, delays or cancellations of flights may be a storm warning from weather forecasters at the departure and destination airfields.
The meteorological minimum required for the safe (normal) take-off and landing of an aircraft is the permissible limits for changes in a set of parameters: wind speed and direction, line of sight, condition of the airfield runway and the height of the lower cloud limit. Bad weather, in the form of intense precipitation (rain, fog, snow and blizzards), with extensive frontal thunderstorms, can also cause the cancellation of flights from the airport.
The values of meteorological minimums may vary for specific aircraft (by their types and models) and airports (by class and the availability of sufficient ground equipment, depending on the characteristics of the terrain surrounding the airfield and the high mountains present), and are also determined by the qualifications and flight experience of the crew pilots , the ship's commander. The worst minimum is taken into account and for execution.
A flight ban is possible in case of bad weather at the destination airfield, if there are not two alternate airports nearby with acceptable weather conditions.
In strong winds, planes take off and land against the air flow (taxiing, for this purpose, to the appropriate runway). In this case, not only safety is ensured, but also the takeoff run distance and landing run distance are significantly reduced. Limitations on the lateral and tailwind components of wind speed, for most modern civil aircraft, are approximately 17-18 and 5 m/s, respectively. The danger of a large roll, drift and turn of an airliner during its takeoff and landing is represented by an unexpected and strong gusty wind (squall).
https://www.meteorf.ru - Roshydromet (Federal Service for Hydrometeorology and Environmental Monitoring). Hydrometeorological Research Center of the Russian Federation.
Www.meteoinfo.ru - new website of the Hydrometeorological Center of the Russian Federation.
Http://193.7.160.230/web/losev/osad.gif - Watch a video animation with a forecast synoptic weather map - precipitation, dynamics of cyclones and anticyclones for the coming days, showing horizontal movements of isobars (atmospheric pressure isolines) of the calculated weather model.
Http://ada.ru/Guns/ballistic/wind/index.htm - For hunters about the effect of wind on the flight of a bullet, a ballistic calculator.
Directory ru.wikipedia.org/wiki/Climate_Moscow - metropolitan weather stations and statistical data on average monthly values of the main weather parameters (temperature, wind speed, cloudiness, precipitation in the form of rain and snow), days when absolute temperature records were recorded, as well as the coldest and warmest years in Moscow and the region.
Https://meteocenter.net/weather/ - Russian weather from the Meteorological Center.
Https://www.ecomos.ru/kadr22/postyMeteoMoskwaOblast.asp - Meteorological network (stations and posts) in the Moscow region. and in neighboring regions (Vladimir, Ivanovo, Kaluga, Kostroma, Ryazan, Smolensk, Tver, Tula and Yaroslavl regions)
Https://www.ecomos.ru/kadr22/sostojanieZagrOSnedelia.asp - environmental reports on the state of environmental pollution in Moscow (weather stations VDNH, Balchug and Tushino) and the region over the past week.
Accepted for use in international synoptic practice. It originally did not include wind speed (added in 1926). In 1955, to distinguish between hurricane winds of different strengths, the US Weather Bureau expanded the scale to 17 points.
It is worth noting that the wave heights in the scale are given for the open ocean, not the coastal zone.
Beaufort points | Verbal definition of wind force | Average wind speed, m/s | Average wind speed, km/h | Average wind speed, knots | Wind action | |
---|---|---|---|---|---|---|
Wind speed km/h | on the sea | |||||
0 | at sea (points, waves, characteristics, height and wavelength) | 0-0,2 | < 1 | 0-1 | Calm. Smoke rises vertically, tree leaves are motionless | Mirror smooth sea |
1 | Mirror smooth sea | 0,3-1,5 | 1-5 | 1-3 | The direction of the wind is noticeable from the drift of the smoke, but not from the weather vane. | There are no ripples, no foam on the crests of the waves. Wave height up to 0.1 m |
2 | There are light ripples on the sea, no foam on the ridges. Wave height is 0.1 m, length - 0.3 m. | 1,6-3,3 | 6-11 | 3,5-6,4 | The movement of the wind is felt by the face, the leaves rustle, the weather vane is set in motion | Short waves with a maximum height of up to 0.3 m, the crests do not overturn and appear glassy |
3 | The ridges do not tip over and appear glassy. At sea, short waves are 0.3 m high and 1-2 m long. | 3,4-5,4 | 12-19 | 6,6-10,1 | The leaves and thin branches of the trees sway all the time, the wind flutters light flags | Short, well defined waves. The ridges, overturning, form glassy foam. Occasionally small lambs are formed. Average wave height 0.6 m |
4 | Short, well defined waves. The ridges, overturning, form a glassy foam, and occasionally small white lambs are formed. The average wave height is 0.6-1 m, length - 6 m. | 5,5-7,9 | 20-28 | 10,3-14,4 | The wind raises dust and debris and moves thin tree branches | The waves are elongated, whitecaps are visible in many places. Maximum wave height up to 1.5 m |
5 | Fresh | 8,0-10,7 | 29-38 | 14,6-19,0 | Thin tree trunks sway, the movement of the wind is felt by the hand | Well-developed in length, but not large waves, maximum wave height 2.5 m, average - 2 m. Whitecaps are visible everywhere (in some cases splashes are formed) |
6 | Strong | 10,8-13,8 | 39-49 | 19,2-24,1 | Thick tree branches sway, telegraph wires hum | Large waves begin to form. White foamy ridges occupy large areas and splashes are likely. Maximum wave height - up to 4 m, average - 3 m |
7 | Strong | 13,9-17,1 | 50-61 | 24,3-29,5 | Tree trunks sway | The waves pile up, the crests of the waves break off, the foam lies in stripes in the wind. Maximum wave height up to 5.5 m |
8 | Very strong | 17,2-20,7 | 62-74 | 29,7-35,4 | The wind breaks tree branches, it is very difficult to walk against the wind | Moderately high long waves. Spray begins to fly up along the edges of the ridges. Strips of foam lie in rows in the direction of the wind. Maximum wave height up to 7.5 m, average - 5.5 m |
9 | Storm | 20,8-24,4 | 75-88 | 35,6-41,8 | Minor damage, the wind begins to destroy the roofs of buildings | High waves (maximum height - 10 m, average - 7 m). The foam falls in wide dense stripes in the wind. The crests of the waves begin to capsize and crumble into spray, which impairs visibility |
10 | Heavy storm | 24,5-28,4 | 89-102 | 42,0-48,8 | Significant destruction of buildings, wind uproots trees | Very high waves (maximum height - 12.5 m, average - 9 m) with long crests curving down. The resulting foam is blown away by the wind in large flakes in the form of thick white stripes. The surface of the sea is white with foam. The strong crash of the waves is like blows |
11 | Fierce Storm | 28,5-32,6 | 103-117 | 49,0-56,3 | Large destruction over a large area. It is observed very rarely. | Visibility is poor. Exceptionally high waves (maximum height - up to 16 m, average - 11.5 m). Small and medium-sized vessels are sometimes hidden from view. The sea is all covered with long white flakes of foam, located downwind. The edges of the waves are blown into foam everywhere |
12 | Hurricane | > 32,6 | > 117 | > 56 | Enormous destruction, buildings, structures and homes were seriously damaged, trees were uprooted, vegetation was destroyed. The case is very rare. | Exceptionally poor visibility. The air is filled with foam and spray. The sea is all covered with stripes of foam |
13 | ||||||
14 | ||||||
15 | ||||||
16 | ||||||
17 |
see also
Links
- Description of the Beaufort scale with photographs of the state of the sea surface.
Wikimedia Foundation.
2010.
See what the “Beaufort Scale” is in other dictionaries:
- (Beaufort scale) at the beginning of the 19th century. English Admiral Beaufort proposed to determine the wind force by the windage that the ship itself or other sailing ships in its visibility can carry at the moment of observation, and to evaluate this force with scale points ... ... Maritime Dictionary A conventional scale for visually assessing the strength (speed) of wind based on its effect on ground objects or on the water surface. Used primarily for ship observations. Has 12 points: 0 calm (0 0.2 m/s), 4 moderate... ...
Dictionary of emergency situations- A scale for determining wind strength, based on a visual assessment of the state of the sea, expressed in points from 0 to 12 ... Dictionary of Geography
Dictionary of emergency situations- 3.33 Beaufort scale: A twelve-point scale adopted by the World Meteorological Organization to approximate wind speed by its effect on objects on land or by waves on the high seas. Source … Dictionary-reference book of terms of normative and technical documentation
A scale for determining wind strength by visual assessment, based on the effect of wind on sea conditions or on land objects (trees, buildings, etc.). Used primarily for observations from sea vessels. Adopted in 1963 by the World... ... Geographical encyclopedia
BEAUFORT SCALE- a conditional scale in points in the form of a table for expressing the speed (strength) of the wind by its effect on ground objects, by rough seas and the ability of the wind to propel sailing ships. The scale was proposed in 1805-1806. British Admiral F. ... ... Dictionary of winds
BEAUFORT SCALE- wind force assessment system. Proposed by the English hydrographer F. Beaufort in 1806. It is based on the visual perception of the effect of wind on the water surface, smoke, flags, ship superstructures, on the shore, and structures. The assessment is made in points... ... Marine encyclopedic reference book
Beaufort scale- a conventional scale in points from 0 to 12 for a visual assessment of the strength (speed) of the wind in points based on roughness at sea or on the effect of ground objects: 0 points (no wind 0 0.2 m/s); 4 moderate wind (5.5 7.9 m/s); 6 strong wind (10.8 13.8 m/s); 9… … Glossary of military terms
BEAUFORT SCALE- In damage management: a conventional scale for visually assessing and recording wind strength (speed) in points or sea waves. It was developed and proposed by the English admiral Francis Beaufort in 1806. Since 1874 it has been adopted for use in... ... Insurance and risk management. Terminological dictionary
The Beaufort scale is a twelve-point scale adopted by the World Meteorological Organization to approximate wind speed by its effect on objects on land or by waves on the high seas. Average wind speed is indicated on... ... Wikipedia
Wind is the horizontal movement of air relative to the earth's surface. This occurs due to uneven distribution of heat and atmospheric pressure. Air flow moves from a high pressure zone to a low pressure zone. The main characteristics of wind are wind speed (strength) and direction. The units of wind speed are meters per second (m/s), kilometers per hour (km/h), and there is a maritime measure of speed - a knot. 1 knot is approximately equal to 0.5 m/s. The direction of the wind is determined by the sides of the horizon, indicated in degrees or in points on a 16-point scale. Wind strength is in points. Average wind speed is determined at a height of 10 meters above a flat, open surface.
The Beaufort scale is a conventional scale that allows you to visually assess the strength (speed) of the wind in terms of the roughness of the sea or its interaction with various objects on the ground. The scale was invented in 1806 by Admiral F. Beaufort, who used it to determine the strength of the wind at sea. Later, in 1874, it was decided to use the Beaufort scale in international synoptic practice on land and at sea. The modified and refined scale is used in maritime navigation. At first, the scale was thirteen points, starting from zero points, when there is no wind, the sea is completely calm. The last, 12th row determines the strength and speed of the wind during a hurricane. Over the years, the scale has changed and been refined, in 1955 the US Weather Bureau increased it to 17 points to distinguish between hurricanes of different strengths.
To quickly and correctly determine the strength and average wind speed on the Beaufort scale, use the table.
Wind force scale (Beaufort scale)
Beaufort points | Wind speed, m/s | Verbal description of the wind | Apparent wind action |
0 | 0,0-0,2 | at sea (points, waves, characteristics, height and wavelength) | The smoke rises vertically, the leaves on the trees are motionless |
1 | 0,3-1,5 | Mirror smooth sea | Light air movement, smoke deviates slightly |
2 | 1,6-3,3 | Easy | The movement of air is felt by the face, the leaves rustle |
3 | 3,4-5,4 | The ridges do not tip over and appear glassy. At sea, short waves are 0.3 m high and 1-2 m long. | Leaves and thin branches on the trees sway |
4 | 5,5-7,9 | Short, well defined waves. The ridges, overturning, form a glassy foam, and occasionally small white lambs are formed. The average wave height is 0.6-1 m, length - 6 m. | Tree tops bend, small branches move, dust rises |
5 | 8,0-10,7 | Fresh | Branches and thin tree trunks sway |
6 | 10,8-13,8 | Strong | Thick branches sway, telephone wires hum |
7 | 13,9-17,1 | Strong | Tree trunks sway, large branches bend, it’s hard to walk against the wind |
8 | 17,2-20,7 | Very strong | Large trees sway, small branches break, it is very difficult to walk |
9 | 20,8-24,4 | Storm | Minor damage to buildings, thick tree branches breaking |
10 | 24,5-28,4 | Heavy storm | Trees break or are uprooted, major damage to buildings |
11 | 28,5-32,6 | Fierce Storm | Great destruction |
12 | 32.7 or more | Hurricane | Devastating destruction |