What wind is considered weak. Technical Library

Leading specialist of the Phobos Center Evgeny Tishkovets told REN TV that at the moment Boeing crash-737 in Rostov-on-Don, the weather conditions were critical for landing the aircraft.

"Western-southwest wind, 12-14 m/s, in gusts up to 17 m/s. As for the actual weather, all of the above is not a dangerous weather phenomenon that restricts or prohibits takeoff or landing aircraft. At least - such as Boeing. It remains to understand with what course he went. The fact is that in Rostov-on-Don the direction runway- northeast-southwest. You need to understand what limitations he had. If we draw an analogy with our domestic types of aircraft, then a side wind of 10, maximum 17 m/s is, for example, critical for the Tu-154. Anything above this will disallow landing.", - explained Tishkovets.

An eyewitness to the Boeing crash told REN TV about what the plane had seen coming in to land. According to the man, at that moment he was sitting in the car, which.

Let's remind, Boeing-737-800 of FlyDubai airline crashed today at 3:50 Moscow time. According to preliminary data, the plane caught fire while still in the air. This is confirmed by the frames,. They show how a bright object falls to the ground, after which a powerful explosion is heard.

Before the crash, the liner circled over the airport for about two hours. There were 55 passengers and 7 crew members on board, all of them died.

Boeing-737-800 is one of the latest models in the 737th line, the most widely used passenger aircraft throughout history civil aviation. The Boeing-737 is so widely used that 1,200 aircraft of this family are in the air at the same time, and one 737 takes off or lands every 5 seconds. Over the entire history of operation, more than 170 liners of this type have been lost, almost 4,000 people have died in accidents.

In Russia, four such aircraft were lost, and all the crashes occurred during landing. The first disaster occurred in Perm in September 2008. Then 88 people died, among the victims of the crash were Hero of Russia Colonel-General Gennady Troshev, First Vice-President of the All-Russian Sambo Federation Vladimir Pogodin. The second incident in Kaliningrad in October of the same 2008 was without casualties - during landing, the crew forgot to release the landing gear. There were 144 people on board, all of them survived. The disaster on November 17, 2013 in Kazan claimed the lives of 50 people. Boeing-737 crashed while entering the second circle. Everyone on board died, including the son of Tatarstan President Rustam Minnikhanov and the head of the local FSB Alexander Antonov.

In 1963, the World Meteorological Organization clarified Beaufort scale and it was adopted for an approximate estimate of wind speed by its effect on ground objects or by waves on the high seas. average speed wind is indicated at a standard height of 10 meters above an open flat surface.

The smoke (from the captain's pipe) rises vertically, the leaves of the trees are motionless. Mirror-like sea.

Wind 0 - 0.2m/s

The smoke deviates from the vertical direction, there are light ripples on the sea, there is no foam on the ridges. Wave height up to 0.1m.

The wind is felt in the face, the leaves rustle, the weather vane starts to move, the sea has short waves with a maximum height of up to 0.3 m.

Wind 1.6 - 3.3m/s.

Leaves and thin branches of trees sway, light flags sway, slight excitement on the water, occasionally small lambs form.

The average wave height is 0.6 m. The wind is 3.4 - 5.4 m/s.

The wind raises dust, pieces of paper; thin branches of trees sway, white lambs on the sea are visible in many places.

Max Height waves up to 1.5 m. Wind 5.5 - 7.9 m/s.

Branches and thin tree trunks sway, the wind is felt by hand, white lambs are visible everywhere.

The maximum wave height is 2.5 m, the average is 2 m. The wind is 8.0 - 10.7 m/s.

In this weather, we tried to leave by Baltic Sea from Darlowo. (Poland) against the wave. In 30 minutes only approx. 10km. and very wet from the splashes. We returned along the way - och. funny.

The thick branches of the trees sway, the thin trees bend, the telephone wires hum, the umbrellas are hardly used; white foamy ridges occupy large areas, water dust is formed. The maximum wave height is up to 4m, the average is 3m. Wind 10.8 - 13.8m/s.

Such weather was caught on boats in front of Rostock. The navigator was afraid to look around, the most valuable thing was stuffed into his pockets, the radio was tied to his vest. Spray from the side waves constantly covered us. For a water-powered fleet, not to mention a simple motorboat, this is probably the maximum ...

Tree trunks sway, large branches bend, it is difficult to go against the wind, the crests of the waves are torn off by the wind. The maximum wave height is up to 5.5m. 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 go against the wind. Strong storm at sea.

The maximum wave height is up to 7.5 m, the average is 5.5 m. The wind is 17.2 - 20.7 m / s.

bend big trees, the wind breaks tiles from the roofs, very strong sea waves, high waves. It is observed very rarely. Accompanied by destruction large spaces. At sea, there are exceptionally high waves (maximum height - up to 16m, average - 11.5m), small vessels are sometimes hidden from view.

Wind 28.5 - 32.6m/s. Violent storm.

The sea is all covered with strips of foam. The air is filled with foam and spray. Visibility is very poor. Full p ... ts small-sized ships, yachts and other ships - it's better not to get hit.

Wind 32.7 m/s or more...

Each a natural phenomenon having different degrees severity, it is customary to evaluate 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 - North wind and so on.). 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 fast moving air masses above the earth's surface.

Features of wind measurement

In order to correctly correlate the data of meteorological services with their real situation or correctly measure, 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 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 North bears his name. Arctic Ocean bordering Canada and Alaska. 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.

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.

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 dangerous heights 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 events 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 the atmospheric front will come to the area where you are, but you also cannot be sure that it will bypass it again. 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 with it unwanted precipitation - in winter it is blizzards 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.

The horizontal movement of air above the Earth's surface is called wind. The wind always blows from an area of ​​high pressure to an area of ​​low pressure.

Wind characterized by speed, strength 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 baric gradient: the greater the baric gradient, the higher the wind speed.

The force of the wind depends on the speed (Table 1). The greater the difference between adjacent areas of the earth's surface, the stronger the wind.

Beaufort scale- a conditional scale for visual assessment of the strength (speed) of the wind in points according to its effect on ground objects or on waves at sea. 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 has changed and refined. The Beaufort scale is widely used in marine 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 on the deflecting effect of the Earth's rotation.

On climate map the prevailing winds are shown by arrows (Fig. 1). The winds observed near the earth's surface are very diverse.

You already know that the surface of land and water heats up in different ways. On a summer day, the land surface heats up more. From heating, the air above the land expands and becomes lighter. Over the pond at this time the air is colder and therefore heavier. If the reservoir 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 land. Such a light breeze is called daytime. breeze(from the French brise - light wind) (Fig. 2, a). The night breeze (Fig. 2, b), on the contrary, blows from the 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 scheme of breezes is shown in fig. 3.

Rice. 1. Scheme of distribution of 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- gusty, cold and strong wind that appears when cold air crosses 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 warms up quickly, and the air pressure over its surface hits. At this time, cooler air begins to move to land. In winter, the opposite is true, so the monsoon blows from land to sea. With the change of the winter monsoon to the summer monsoon, dry, slightly cloudy weather changes to rainy.

The effect of the monsoons is strong in eastern parts continents, where they are adjacent to vast expanses of oceans, so such winds often bring heavy rainfall to the continents.

The unequal nature of the circulation of the atmosphere in different areas the globe determines the differences in the causes and nature of the monsoons. As a result, extratropical and tropical monsoons are distinguished.

Rice. 2. Breeze: a - daytime; b - night

Rice. Fig. 3. Scheme of breezes: a - in the afternoon; 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 fluctuations in pressure over the sea and land. The most typical area of ​​their distribution is Far East, Northeast China, Korea, to a lesser extent - Japan and northeast coast Eurasia.

tropical monsoons - monsoons of tropical latitudes. They are due to seasonal differences in the 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 given time summer. Tropical monsoons are most typical and persistent in the northern part of the basin indian ocean. This is largely facilitated by the seasonal change in the atmospheric pressure regime 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 regions of the globe is less characteristic when one of them, the winter or summer monsoon, is more clearly expressed. Such monsoons are observed in Tropical Africa, in northern australia and in equatorial regions of South America.

Earth's constant winds - trade winds And westerly winds- depend on the position of atmospheric pressure belts. Since low pressure prevails in the equatorial belt, and near 30 ° N. sh. and yu. sh. - high, near the surface of the Earth throughout the year the winds blow from the thirtieth latitudes to the equator. These are trade winds. Under the influence of the rotation of the Earth around its axis, the trade winds deviate to the west in the Northern Hemisphere and blow from the northeast to the southwest, and in the Southern they are directed from the southeast to the northwest.

From the high pressure belts (25-30°N and S), the winds blow not only towards the equator, but also towards the poles, since at 65°N. sh. and yu. sh. 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, westerly winds prevail in temperate latitudes.

// Classification of wind strength, sea waves, and visibility at sea

Classification of wind strength, sea waves, and visibility at sea

Beaufort scale

0 points - calm
A mirror-smooth sea, almost motionless. Waves practically do not run up to the shore. The water is more like a quiet backwater of a lake than sea ​​coast. Haze may be observed above the surface of the water. The edge of the sea merges with the sky so that the border is not visible. Wind speed 0-0.2 km/h.

1 point - quiet
Light ripples on the sea. The height of the waves reaches up to 0.1 meters. The sea can still merge with the sky. There is a light, almost imperceptible breeze.

2 points - easy
Small waves, no more than 0.3 meters high. The wind speed is 1.6-3.3 m/s, you can feel it with your face. With such a wind, the weather vane begins to move.

3 points - weak
Wind speed 3.4-5.4 m/s. Slight roughness on the water, occasionally lambs appear. The average wave height is up to 0.6 meters. A weak surf is clearly visible. The weather vane spins without frequent stops, the leaves on the trees, flags and so on sway.

4 points - moderate
Wind - 5.5 - 7.9 m / s - raises dust and small pieces of paper. The weather vane spins continuously, the thin branches of the trees bend. The sea is restless, in many places lambs are visible. Wave height up to 1.5 meters.

5 points - fresh
Almost the entire sea is covered with white lambs. Wind speed 8 - 10.7 m/s, wave height 2 meters. Branches and thin tree trunks sway.

6 points - strong
The sea in many places is covered with white ridges. The height of the waves reaches 4 meters, the average height is 3 meters. Wind speed 10.8 - 13.8 m/s. Thin tree trunks bend, and thick branches of trees, telephone wires buzz.

7 points - strong
The sea is covered with white foamy ridges, which are blown off the surface of the water from time to time by the wind. The wave height reaches 5.5 meters, the average height is 4.7 meters. Wind speed 13.9 - 17.1 m/s. Medium tree trunks sway, branches bend.

8 points - very strong
Strong waves, foam on each crest. The height of the waves reaches 7.5 meters, the average height is 5.5 meters. Wind speed 17.2 - 20 m/s. It is difficult to go against the wind, it is almost impossible to talk. Thin branches of trees break.

9 points - storm
High waves on the sea, reaching 10 meters; average height 7 meters. Wind speed 20.8 - 24.4 m/s. Large trees bend, medium branches break. The wind rips off poorly reinforced roof coverings.

10 points - strong storm
The sea is white. Waves crash on the shore or on the rocks with a crash. The maximum wave height is 12 meters, the average height is 9 meters. The wind, at a speed of 24.5 - 28.4 m/s, rips off roofs, significant damage to buildings.

11 points - fierce storm
High waves reach 16 meters, with an average height of 11.5 meters. Wind speed 28.5 - 32.6 m/s. Accompanied by great destruction on land.

12 points - hurricane
Wind speed 32.6 m/s. Serious damage to capital buildings. The wave height is over 16 meters.

Sea wave scale

In contrast to the generally accepted twelve-point system for estimating wind, there are several estimates of sea waves. British, American and Russian grading systems are generally accepted. All scales are based on a parameter that determines average height significant waves (according to the site savelyev.info). This setting is called Significance Wave Height (SWH). In the American scale, 30% of significant waves are taken, in the British 10%, in the Russian 3%. Wave height is measured from the crest (the top of the wave) to the trough (the base of the trough).
Below is a description of the height of the waves.

0 points - calm
1 point - ripples (SWH< 0,1 м)
2 points - weak waves (SWH 0.1 - 0.5 m)
3 points - light waves (SWH 0.5 - 1.25 m)
4 points - moderate waves (SWH 1.25 - 2.5 m)
5 points - rough sea (SWH 2.5 - 4.0 m)
6 points - very rough sea (SWH 4.0 - 6.0 m)
7 points - strong sea (SWH 6.0 - 9.0 m)
8 points - very strong sea (SWH 9.0 - 14.0 m)
9 points - phenomenal sea (SWH > 14.0 m)
In this scale, the word "storm" is not applicable. Since it is not determined by the strength of the storm, but by the height of the wave. Storm is defined by Beaufort.
For the WH parameter for all scales, it is precisely a part of the waves (30%, 10%, 3%) that is taken because the magnitude of the waves is not the same. At a certain time interval there are waves, for example, 9 meters, as well as 5, 4, etc. Therefore, for each scale, its own SWH value was adopted, where a certain percentage of the most high waves. There are no instruments for measuring wave height. Therefore, there is no exact definition of the score. The definition is conditional.
On the seas, as a rule, the wave height reaches 5-6 meters in height, and up to 80 meters in length.

Visibility scale

Visibility is the maximum distance at which objects are detected during the day and navigation lights at night. Visibility depends on weather conditions. In metrology, the influence of weather conditions on visibility is determined by a conditional scale of points. This scale is a way of indicating the transparency of the atmosphere. Distinguish between day and night visibility. Below is a daily scale for determining the range of visibility.
Up to 1/4 cable
About 46 meters. Very poor visibility. Thick fog or blizzard.
Up to 1 cable
About 185 meters. Bad visibility. Thick fog or sleet.
2-3 cables
370 - 550 meters. Bad visibility. Fog, wet snow.
1/2 mile
About 1 km. Haze, thick haze, snow.
1/2 - 1 mile
1 - 1.85 km. Average visibility. Snow, heavy rain
1 - 2 miles
1.85 - 3.7 km. Haze, mist, rain.
2 - 5 miles
3.7 - 9.5 km. Light haze, haze, light rain.
5 - 11 miles
9.3 - 20 km. Good visibility. Visible horizon.
11 - 27 miles
20 - 50 km. Very good visibility. The horizon is clearly visible.
27 miles
Over 50 km. Exceptional visibility. The horizon is clearly visible, the air is transparent.