Strong wind from the sea title. sea ​​wind

Chapter V. HYDROMETEOROLOGICAL AND ICE PHENOMENA ON INLAND WATERWAYS

§ 24. ELEMENTS AND TYPES OF WIND

The wind is characterized by two elements: direction and speed.

The direction of the wind is determined by the compass by that part of the horizon from where it blows. They say: "The wind blows into the compass." Therefore, the direction of the wind can be: north, northwest, southeast, west, etc.

On rivers, the direction of the wind is often determined relative to the flow of the river: the wind can be upstream (blowing in the direction of the current) and downstream (blowing against the current).

Depending on which side the wind is blowing from, the ship has a windward side (the side facing the wind) and a lee side (opposite to the windward).

Relative to the direction of the vessel's movement, the wind can be head and tail.

The wind blowing towards the shore at a right or slight angle to it is called bulk wind, and the wind blowing from the shore towards the river or lake is called dump wind. Thus, for one coast the wind will be dump, for the other - bulk. The same for the ship - depending on which coast it is on.

If the direction of the wind is determined on a stationary ship, then it is called true and "(Fig. 50). When the ship moves, a stream of air arises, which is called the course wind . The course wind has the speed of the vessel and is directed in the direction opposite to its movement. On a moving vessel, ka-

Table 15

chewing (pennant) wind Ik. It is directed along the resultant of the true and course wind.

Wind speed is usually measured in meters per second or kilometers per hour. Wind speed is also measured by points Wind speed gradations used for forecasts and warnings are given in Table. fifteen.

AT practical work it is often necessary to go from wind speed to points or from points to wind speed in meters per second. The entire recalculation can be done in the mind, using the data in Table. 16. In this case, fractional numbers are rounded up to integers; values ​​of 0.5 or more are rounded to one; values ​​less than 0.5 are discarded.

For a rougher estimate than indicated in the table, when going to points, the speed in meters per second is halved (point = speed, m / s: 2), and when moving to speed, the points are doubled (velocity, m / s == 2 X score),

At coastal stations, the direction and strength of the wind is determined by a weather vane and an anemometer (Fig. 51).

On a ship, the speed of the apparent wind is measured by an anemometer, and the direction is measured by smoke, a flag, a pennant. For ships towing a train or a raft at a speed of 3-4 km / h, the true and apparent winds are almost the same.

The anemometer (see Fig. 51) has four hemispheres that rotate under the influence of the wind. On the dial with counters determine

Table 1b

Rice. 51. Anemometer

Rice. 52. Wind rose

change the number of revolutions. Then, according to the conversion factor given in the anemometer certificate, and the number of revolutions, the wind speed is obtained.

Sometimes, to determine the direction of the wind, small cloth cones, called "sorcerers", are installed in open places on ships.

The strength of the wind can also be determined by the scale visual evaluation, which is given in the appendix. l.

Having materials of wind observations, it is possible to determine the frequency of each direction and different wind speeds. For clarity, the repeatability is depicted graphically in the form of a “wind rose” (Fig. 52). The latter is built in the following way.

First, draw lines along eight points (C, NE, E, SE etc.). On the lines of the rhumbs, on a scale, segments are plotted that are proportional to the repeatability of the direction or speed of the wind, expressed as a percentage. Repeatability is plotted from a circle of calms, the radius of which is equal to the number of percentages of calms in the accepted scale. By connecting the ends of the segments, a figure is obtained - a wind rose, which gives an idea of ​​the distribution of winds at a given point in direction and speed. Wind roses are built for a month or a year.

Winds that occur for local reasons and cover small areas are called local. The main types of such winds are as follows.

Breeze - a wind that has a direction from a reservoir to land during the day (sea breeze), and at night - from land to a reservoir (coastal breeze). Usually, breezes spread up to 50 km inland and somewhat more inland. The main reason for the occurrence of a breeze is the uneven heating and cooling of land and water during the day, as a result of which air circulation occurs.

Bora - "falling" cold and strong wind directed from the coastal hill to the sea. In the Soviet Union, such a wind is observed in the region of Novorossiysk and Novaya Zemlya, where the wind strength reaches 50-60 m/s.

Sarma is a "falling" north-west wind blowing on the western shore of Lake Baikal at a speed of up to 40 m/s. Baku Nord is usually a strong, dry and cold north wind, reaching a speed of 20-40 m/s. In a swimming pool mediterranean sea bora is found on the coast of the Adriatic Sea (Fiume, Trieste), but the wind strength in this area is much less. The bora-like wind seen in Provence is called the mistral. A very warm and humid wind, accompanied by significant cloudiness and precipitation and observed in Italy, Arabia, Palestine and Mesopotamia, is called sirocco, in Spain - levesh, in Algeria and Tunisia - samum, in Egypt - shamsin.

The winds of bora, sarma, Baku north are also called falling. They last for several days. Incident winds are formed due to a significant difference in atmospheric pressure over land and over a body of water, where it is less. Air masses, moving from the side of the land to the reservoir in the direction of lower pressure, accumulate behind the ridges of the mountains and begin to rise up (Fig. 53). The air temperature drops as it rises, and the humidity gradually increases. With a further rise, the rate of decrease in air temperature is less, since here there is a release of latent heat, which is released during the condensation of water vapor. At the top of the ridge, where the air is supersaturated with water vapor, a cloudy shaft appears, covering the entire mountain range.

From the height of the ridge, the air rushes to the reservoir, heats up and comes to the coast with a higher temperature than at the height and little moisture. Cold air, passing through a mountain range, acquires a greater speed due to the pressure difference on land and water, as well as due to the effect of gravity of the air mass.

Although the air is dynamically heated, it comes down comparatively cold, since its initial temperature is low and the mountains are low. The vertical power of such a "falling" wind as bora does not exceed 200-300 m. The bora spreads for several kilometers from the coast.

Rice. 53. To the formation of a local wind - pine forests

Rice. 54. The influence of the coast on the direction of the wind:

a-the wind blows from the high bank; b-the wind blows from the river to the shore; in-wind crosses a narrow channel

A powerful fall of cold air creates strong waves in the coastal zone and causes icing of ships and port facilities.

Having received a forecast of falling winds, navigators should take measures to shelter ships in the berthing line of the port (where a small calm zone is formed at a distance of several hundred meters from the shore) or in natural shore shelters indicated in the sailing directions.

With the formation of reservoirs in the wind regime of a given area, great changes occur and local winds. This is due to the fact that instead of the rough surface of the earth, a vast expanse of water appears. Usually in such cases, the strength of the wind increases, the frequency of calm decreases and the direction of the prevailing winds changes.

The wind, in contact with the surface of the earth or water, due to friction somewhat, subsides, so the wind speed increases with height. It is believed that when moving from land to water, the wind speed increases by an average of 30%. However, the increase in wind speed is also associated with local features of the relief of the banks of the reservoir. At low and open shores, the average wind speeds increase by almost 1.5 times, and under wooded and high shores, on the contrary, the wind speed decreases.

The influence of obstacles on the air flow is diverse. It depends on the size and shape of the obstacles, on their location in relation to the wind, on the wind speed and the state of the atmosphere. For example, a wind blowing from a mountain retains its direction only at the opposite shore. Directly under the mountain, the wind takes the opposite direction. Consequently, the wind observed on the approach to the mountain as dump wind, in fact, near it will be bulk. Dangerous for ships are ruptures of high banks by tributary valleys, ravines. Through these gaps, the wind “falls” with great force onto a river or reservoir.

Let's analyze some typical cases (Fig. 54).

When the wind blows due to a coastal separate obstacle, a wind shadow is created near the latter, and at a certain distance, a vortex with a horizontal axis and a wind of the opposite direction is created.

When the wind blows from the river to the shore, landing stage, etc., a wind of almost the opposite direction arises near them. The action of the reverse wind affects at a distance equal to approximately the height of the obstacle.

The wind crossing the river from the side of the high bank changes direction almost to the opposite. The change in direction occurs clockwise and affects a distance equal to one or two coast heights.

High and indented coasts change the speed of the wind blowing from the coast, giving the wind in the coastal strip an unstable direction and gustiness.

The strength and direction of the wind do not remain constant for a long time. In steady weather, the wind can increase, gust, then weaken.

§ 25. WIND WAVES

By origin, waves are divided into wind, tidal, anemobaric, earthquake (tsunami) and ship waves. The most common are wind waves, i.e. waves caused by the wind, which are under its influence.

Wind waves - the process of formation, development and propagation of waves caused by wind in the waters of the oceans, seas and other basins.

With a weak wind and reaching a speed of 0.25-1.0 m / s, waves of very small sizes appear on the surface of the water, called ripples. When the wind increases, the water surface goes out of balance. It returns to equilibrium under the influence of the gravitational force, i.e. gravity.

Gravitational wind waves are waves caused by the wind, in the formation of which gravity plays the main role.

There are the following elements of excitement.

Wave profile / (Fig. 55) - a curve obtained as a result of a section of the rough sea surface by a vertical plane in a given direction.

Average wave level of the wave profile 2 - a line crossing the wave profile so that the total areas above and below this line are the same.

wave crest 3 - the part of the wave above the average wave level.

top of the wave 4 - highest point wave crest.

wave hollow 6 - part of the wave located below the average wave level.

The bottom of wave 5 is the lowest point of the wave trough.

wave height hy- the excess of the top of the wave over the adjacent sole on the wave profile, drawn in the general direction of wave propagation.

Wave crest height - the excess of the wave top above the average wave level on a wave profile drawn in the general direction of wave propagation.

D
wave length TO - horizontal distance between the tops of two adjacent crests on a wave profile drawn in the general direction of wave propagation.

Rice. 55. Elements of excitement

The length of the crest is the horizontal distance between the bottoms of two adjacent troughs on a wave profile drawn perpendicular to the general direction of wave propagation.

Wave period t is the time interval between the passage of two adjacent wave peaks through a fixed vertical.

The direction of wave propagation is the direction of wave movement, determined in a short time interval - of the order of the wave period, or the direction of the wave beam.

Wave speed v- the speed of movement of the wave crest in the direction of wave propagation, determined over a short time interval of the order of the wave period.

Windward slope of a wave - part of the wave from the bottom of the seam to the top, facing the wind.

The lee slope of a wave is the part of the wave from the top to the bottom, closed from the wind.

Wave front - a line on the plan of a rough surface, passing along the tops of the crest of a given wave, which are determined by a set of wave profiles drawn parallel to the general direction of wave propagation.

A wave ray is a line perpendicular to the wave front at a given point.

Due to the uneven impact of the wind, the waves have a variety of types and shapes.

Swell - wind-induced waves that propagate in the wave formation area after the wind weakens and changes its direction, or wind-induced waves that come from the wave formation area to another area where the wind blows with a different speed and direction.

Dead swell - waves previously caused by the wind that propagate in the absence of wind.

Capillary to wind waves - waves caused by the wind, in the formation of which the main role is played by the force of surface tension.

Secondary waves - small waves on the surface of large waves.

Regular wave - wave in which the form and elements of all waves are the same.

Irregular waves - waves in which the shape and elements of the waves change from one wave to another.

Two-dimensional wave - a set of waves, the average length of the crest of which is many times greater than the average wavelength.

Three-dimensional excitement - a set of waves, the average length of the crest of which is several times greater than the average wavelength.

It is believed that at L / X 3-4 waves are three-dimensional (L- average comb length; X is the average wavelength).

A developing wind wave is a wind wave in which wave heights increase with time.

A steady wind wave is a wind wave in which the statistical characteristics of the waves do not change in time.

Attenuated wind waves - wind waves in which wave heights decrease with time.

The maximum wave elements in some basins are given in Table. 17.

As the wave profile moves, the surface of the water drops. Therefore, under the windward ridge, water particles move downward. Under the wave base, the particles move towards the wave motion, then they rise under the windward slope of the wave, after which the movement of water particles is repeated.

The wind wave profile is not symmetrical. Its leeward side is steeper than its windward side. At the tops of wind waves, ridges are formed, the tops of which collapse under the action of the wind, forming foam (lambs), and break off in strong winds.

The direction of the wind and the direction of wind waves in the open sea, as a rule, coincide or differ by 30-40%.

Wind waves, the propagation of which is affected by the depth of the reservoir, are called shallow water waves. These waves occur where the depth of the reservoir is less than half the wavelength.

The radii of the circles along which water particles move at depth decrease, so the excitement fades with depth.

Deep waves are characterized by the fact that their crests and bottoms at depth are located under the crests and bottoms of the waves on the surface of the water; wavelength, velocity and period do not change at depth;

the diameter of the orbit and the height of the wave decrease exponentially with depth. For example, when the depth h is equal to the wavelength X, then the waves have a height 500 times less than on the surface, i.e., there is practically no excitement. At a depth equal to 0.5X the wave height is 0.04h, at a depth of 0.3-0.15h, at a depth of 0.1X-0.53h.

Table 17

The wind, creating waves, transfers a certain energy to them. The wave energy is made up of kinetic energy the motion of water particles in orbit and the potential energy that a particle has when moving from a calm level to a surface in waves. The energy of a wave is directly proportional to the square of its height, length and distance along the crest. Due to the fact that the height of the wave decreases with depth, the waves of the upper layers of water have the highest energy.

When a wave encounters an obstacle, the energy contained in it transforms into impact energy. This explains the reason why the waves cause great destruction.

In addition to those listed above, there are also the following types of excitement.

Crowd - chaotic excitement arising from the interaction of waves running in different directions. With a crush, the height and steepness of the wave increase and the force of its impact increases. Once in the crowd, the vessel may lose control.

Burun - foamy masses of water formed on the crest of a wave during its destruction. A breaker occurs on the shallows without a direct impact of the wave on the shore, when, due to friction against the bottom, the crest overtakes the hollow of the wave and collapses forward.

O
crashing shaft - a wave, the crest of which, due to a decrease in depth, is deformed and collapses.

Run-up - a reciprocating flow caused by the collapse of waves, running onto a shallow coast.

Reverse faults - columns of water formed when running up steep banks.

Surf - waves breaking in the coastal zone. The wave, leaving in shallow water, reaches the critical depth, which has a value equal to 2-3h. In this case, the wave collapses, breaks and breakers form. In a breaking wave, water particles have both orbital and translational motion, so floating objects move towards the shore in jolts and then are thrown onto it. At the same time, a reverse movement towards the sea is created along the bottom. A broken wave has a strong effect on structures and is dangerous for them.

The elements of the waves and the direction of their movement can change significantly during interference, refraction and diffraction.

Rice. 56. Refraction (a) and diffraction (b) of wind waves

The interference of wind waves occurs when they are superimposed on each other, as a result of which the original waves can either increase or decrease. Interference is observed when the wind direction changes or when waves are reflected from steep banks. Interference can produce a standing wave whose profile does not move and the nodal points remain in place. Standing waves are dangerous for rafts, as they destroy them.

Refraction of wind waves - the transformation of wind waves with an oblique approach of wave crests to isobaths (Fig. 56, a). When approaching the shore, due to the friction of water particles on the bottom, the speed of the wave movement decreases. With an oblique approach of a wave to the coast, the part of the wave closest to the coast is located at shallower depths, so the speed of its advance decreases, and the parts of the wave located at greater depths continue to move at the same speed. As a result, the wave, as it were, unfolds, trying to become parallel to the shore. Therefore, regardless of the direction of the wave in the open part of the reservoir, it always approaches the shore at a small angle.

Diffraction of wind waves is a change in the structure of wind waves when they go around obstacles (Fig. 56, b). Diffraction is observed near the islands and protective structures, around the turns of the deep banks, in the areas of the expansion of reservoirs.

Unrest in reservoirs has much in common with unrest at sea. Here the waves, as a rule, have a lower height than sea waves, but they are steeper than them. The predominant ratio of wavelength to height for sea waves is in the range of 15-40, and for reservoir waves 10-20. Wave heights on reservoirs and lakes are different:

on the Kama reservoir - up to 1.8 m, Gorky - up to 1.7 m, Rybinsk - up to 2.5, Kuibyshev - up to 3.2, Tsimlyansk - up to 3.0, on Onega lake- up to 3.0, on Lake Baikal - up to 3.5 m. The smaller the reservoir, the lower and steeper the waves on it. On small lakes, the wave height does not exceed 0.5 m.

Excitement on the reservoir in its various regions is not the same. It depends on the acceleration of the wave, the topography of the coast and bottom, vegetation, etc.

Bushes, flooded at great depths in the lower zone, do not interfere with the development of waves; in middle zone, being at a depth of 2-3 m, it has a braking effect on the waves. The forest, flooded at the bottom of the reservoir, reduces the size of the waves at shallow depths, creates a wave refraction, and sometimes a crowd.

On shallow lakes and in reservoirs, due to shallow depths, crowding is also created during waves. It often occurs when waves are reflected from the shore. When the wind subsides, the waves on the reservoirs quickly disappear, usually there is no swell.

The wave regime of the outport of the upper pool depends on the orientation and size of the entrance to the outport, the magnitude of the waves coming from the reservoir and created in the water area of ​​the outport, the type of walls, etc. Usually the wave in the outport does not exceed 0.5-1.0 m.

Waves in the water area of ​​the outport are created as a result of the interference of local waves and waves coming from the reservoir. The waves penetrating the outport turn into long and gentle waves of the swell type, and at the remote points of the outport the waves become insignificant. The local waves of the outport are, as a rule, steep and short, their height is 0.5-1 m.

In the lower reaches of the rivers, especially with winds blowing against the current, a steep wave 1.5-2 m high develops.

Sea mouths of rivers have excitement characteristic of coastal sea areas. At the mouths of the Amur, Yenisei, and Ob rivers, waves up to 3 m or more are observed.

Depending on the conditions of the wind wave regime, the waterways, according to the Rules of the River Register of the RSFSR, are divided into the following four categories:

"M" (marine) at altitude and wavelength 3.0 X 40 m;

"O" (lake), respectively, at 2.0 X 20 m;

"R" (river) - at 1.2 X 12 m;

"L" (light) at a height and wavelength less than 1.2 X 12 m,

Certain sections of the waterway are assigned to one category or another, based on observational data and calculations of wave sizes.

Of the total length of internal waterways the so-called small rivers stand out. The assignment of rivers to the category of small rivers is conditional and is established by the list approved by the Ministry of River Fleet of the RSFSR.

wind formation

Although the air is invisible to the eye, we always feel its movement - the wind. The main reason for the occurrence of wind is the difference in atmospheric pressure over areas of the earth's surface. As soon as the pressure somewhere decreases or increases, the air will move from the place of greater pressure to the side of less. And the pressure equilibrium is disturbed by the unequal heating of various parts of the earth's surface, from which the air also heats up differently.

Let's try to imagine how this happens on the example of the wind that occurs on the coasts of the seas and is called breeze. Areas of the earth's surface - land and water - are heated differently. Dry dol heats up faster. Therefore, the air above it will heat up faster. It will rise up, the pressure will decrease. Over the sea at this time, the air is colder and, accordingly, the pressure is higher. Therefore, air from the sea moves to land in place of warm air. Here the wind blew - afternoon breeze. At night, everything happens the other way around: the land cools faster than the water. Above him cold air creates more pressure. And above the water, it retains heat for a long time and cools slowly, the pressure will be lower. Cold air from the land from the area high pressure moves towards the sea, where the pressure is less. Arises night breeze.

Therefore, the difference in atmospheric pressure acts as a force, causing horizontal movement of air from an area of ​​high pressure to an area of ​​low pressure. This is how the wind is born.

Determination of wind direction and speed

The direction of the wind is determined beyond the side of the horizon from which it blows. If, for example, the wind blows from the event, it is called westerly. This means that the air moves from west to east.

Wind speed depends on atmospheric pressure: the greater the difference in pressure between areas of the earth's surface, the stronger the wind. It is measured in meters per second. Near the earth's surface, winds often blow at a speed of 4-8 m / s. In ancient times, when there were no instruments yet, the speed and strength of the wind was determined by local signs: at sea - by the action of the wind on the water and sails of ships, on land - by the tops of trees, by the deflection of smoke from pipes. For many features, a 12-point scale was developed. It allows you to determine the strength of the wind in points, and then its speed. If there is no wind, its strength and speed are equal to zero, then this is calm. Wind with a force of 1 point, barely swaying the leaves of trees, is called quiet. Next on the scale: 4 points - moderate wind(5 m / s), 6 points - strong wind(10 m / s), 9 points - storm(18 m/s), 12 points - Hurricane(Over 29 m/s). At weather stations, the strength and direction of the wind is determined using weather vane, and the speed is anemometer.

The strongest winds near the earth's surface blow in Antarctica: 87 m / s (individual gusts reached 90 m / s). The highest wind speed in Ukraine was recorded in the Crimea on grief- 50 m / s.

Monsoon is a periodic wind that carries a large amount of moisture, blowing from land to ocean in winter, and from ocean to land in summer. Monsoons are observed mainly in the tropical zone. Monsoons are seasonal winds that last for several months each year in tropical areas. The term originated in British India and nearby countries as the name for the seasonal winds that blow from the Indian Ocean and the Arabian Sea to the northeast, bringing significant amounts of precipitation to the region. Their movement towards the poles is caused by the formation of areas of low pressure as a result of the heating of tropical regions during the summer months, that is, Asia, Africa and North America from May to July and in Australia in December.

The trade winds are constant winds blowing with a fairly constant force of three or four points; their direction practically does not change, only slightly deviating. The trade winds are called the near-surface part of the Hadley cell - the predominant near-surface winds that blow in the tropical regions of the Earth in a westerly direction, approaching the equator, that is, northeast winds in the Northern Hemisphere, and southeast winds in the South. The constant movement of the trade winds leads to the mixing of the Earth's air masses, which can manifest itself on a large scale: for example, the trade winds blowing over the Atlantic Ocean are capable of carrying dust from the African deserts to the West Indies and parts of North America.

Local winds:

Breeze - a warm wind blowing from the coast to the sea at night and from the sea to the coast during the day; in the first case it is called a coastal breeze, and in the second - a sea breeze. Important effects of the formation of predominant winds in coastal areas are sea and continental breezes. The sea (or smaller body of water) heats up more slowly than land due to the greater heat capacity of water. Warmer (and therefore lighter) air rises over land, creating zones reduced pressure. As a result, a pressure difference is formed between land and sea, which is usually 0.002 atm. Due to this pressure difference, the cool air over the sea moves towards the land, creating a cool sea breeze on the coast. Due to the lack of stronger winds, the speed of the sea breeze is proportional to the temperature difference. If there is wind from the land side with a speed of more than 4 m/s, the sea breeze usually does not form.

At night, due to the lower heat capacity, the land cools faster than the sea, and the sea breeze stops. When the temperature of the land falls below the temperature of the surface of the reservoir, a reverse pressure drop occurs, causing (in the absence of a strong wind from the sea) a continental breeze that blows from the land to the sea.

Bora is a cold, sharp wind blowing from the mountains to the coast or valley.

Foehn - a strong warm and dry wind blowing from the mountains to the coast or valley.

Sirocco is the Italian name for a strong southerly or southwesterly wind that originates in the Sahara.

Variable and constant winds

variable winds change their direction. These are the sprays already known to you (from the French "Breeze" - light wind). They change their direction twice a day (day and night). Splashes occur not only on the coasts of the seas, but also on the shores of large lakes and rivers. However, they cover only a narrow strip of the coast, penetrating deep into the land or sea for several kilometers.

Monsoons formed in the same way as breezes. But they change their direction twice a year according to the seasons (summer and winter). Translated from Arabic, "monsoon" means "Season". In summer, when the air over the ocean heats up slowly and the pressure over it is greater, moist sea air penetrates the land. This is the summer monsoon that brings daily thunderstorms. And in winter, when high air pressure is established over land, the winter monsoon begins to operate. It blows from land towards the ocean and brings cold, dry weather. So, the reason for the formation of monsoons is not daily, but seasonal fluctuations in air temperature and atmospheric pressure over the mainland and ocean. Monsoons penetrate the land and ocean for hundreds and thousands of kilometers. They are especially common on the southeastern coast of Eurasia.

Unlike variables, constant winds blow in the same direction throughout the year. Their formation is associated with high and low pressure belts on Earth.

trade winds- Winds that blow throughout the year from high pressure zones near the 30th tropical latitudes of each hemisphere to a low pressure zone at the equator. Under the influence of the rotation of the Earth around its axis, they are not directed directly to the equator, but deviate and blow from the northeast in the Northern Hemisphere and from the southeast - in the Southern Hemisphere. The trade winds, characterized by uniform speed and amazing constancy, were the favorite winds of navigators.

From tropical zones of high pressure, winds blow not only towards the equator, but also in the opposite direction - towards the 60th latitude with low pressure. Under the influence of the deflecting force of the Earth's rotation, with distance from tropical latitudes, they gradually deviate to the east. This is how air moves from west to east and these winds in temperate latitudes become Western.

Wind is a stream of air moving in nature horizontally relative to the earth. We do not see it, but if we stand facing the wind, then we feel a pleasant touch, incomparable to anything. The wind can be: warm, cold, gusty, hurricane, frosty, strong, weak. It can be everywhere, whether it is a city or a village, rivers or mountains, seas or oceans.

Wind is formed due to the fact that some parts of the earth warm up unevenly, thereby forming warm or cold air. The wind blows from an area of ​​high pressure to a low one, i.e. Earth's poles are high pressure, while the equator is low pressure. From the south direction of the earth, the wind blows to the left, from the north to the right, this is due to the rotation of the earth. An anticyclone is created when dense layers of air collide with less dense layers, and they move more slowly.

There are monsoon winds and there are trade wind winds, these are the two main circulating currents over our planet.

trade winds blow from the tropics, because they form in areas of high pressure and move towards the equator, which is in areas of low pressure. And as the earth rotates, these generated winds begin to blow in a southerly direction. The countries that are most affected by the trade winds are South America, Australia, the winds that form there over the oceans bring rain almost all year round. In North Africa, the winds blow from the center of Asia, so they are always hot and dry. Thus, in the direction of the wind, you can understand where the famous Sahara Desert came from. And the winds that blow from there are always dry, not bringing moisture.

Monsoons are changing winds. They blow at certain times of the year, which is where they got their name from (Arab Mavsim - season). In summer, monsoons blow from the sea to land, in winter, on the contrary, this happens due to the fact that on the mainland in warm time During the year, the air heats up rapidly, expands and rises, forming an area of ​​low pressure. And at this time, the air over the ocean warms up more slowly, thus it turns out that the wind begins to blow on land, bringing wet air and rain. In winter, everything happens the other way around, the ocean cools more slowly, a low pressure area forms on it, which meets with a high pressure area coming from the mainland, so the monsoon that comes from the ocean will be cold and dry.

Bora is a strong, sharp, squally wind that moves at high speed even at low temperatures. Basically, this wind comes from the tops of the mountains and descends closer to water bodies, lakes, seas, and can last for several days. Actually, due to the fact that the mountains divide the terrain and the bora wind is formed, the difference between the temperature of the wind and the temperature formed over the reservoir makes the wind move even stronger. Shipwrecks often occur due to the fault of these winds.

Föhn- this kind of winds is a bit similar to the bora wind. The hair dryer also moves from the mountains to the coast at its high enough speed it is a warm, light breeze. Most often, such a wind prevails in mountainous areas, and thanks to the blow of a hair dryer, snow melts, avalanches descend, and high evaporation of moisture occurs.

Breeze- this is the wind blowing from the side of reservoirs of lakes, seas. Its direction is directly dependent on temperature changes, so it can circulate and change its direction several times a day. Basically, the daytime breeze moves from the side of the reservoir to land, at night, on the contrary, from the cooled coast towards the water.

Tornado- in other words, it is a tornado. Due to the strong difference in atmospheric pressure, a funnel is formed. A funnel is formed under cumulus rain clouds and descends to the very ground. A tornado moves with great force and speed, pulling in and destroying everything in its path. Also, when driving, you can hear a strong hum and roar. The power of this wind is so strong that it easily lifts cars, houses, and heavy objects into the sky.

Sukhovey- this is a hot wind that blows most often in the flat, steppe and desert zones. It can last for several days and due to strong high temperature at low humidity of the area, it dries the air, dries out the soil, which adversely affects the fertility of the land. And with prolonged dry winds, a drought occurs altogether.

Zephyr- a pleasant, warm, light breeze that brings moisture and got its name from the ancient Greek god Zephyr, which blew in the Mediterranean. This wind is observed most often in summer, and it can be both warm and light, and cool bringing heavy rains.

Wind, a word that implies so much in itself, is both a gentle breath that we see and feel on a warm summer day and destructive hurricanes that rip and sweep away everything that they meet in their path.

Blowing towards land. Usually starts in the morning, reaches top speed in the afternoon, subsides by the time of sunset, giving way to night coastal breeze blowing towards the pond. Sometimes it penetrates far inland. For example, in Saudi Arabia it penetrates 200–225 km at a speed of up to 7 m/s, covering the atmospheric layer up to a height of more than 1200 m. depends on the relief and direction of the coastline. Wed .

Dictionary of winds. - Leningrad: Gidrometeoizdat. L.Z. Proh . 1983

See what "SEA WIND" is in other dictionaries:

SEA WIND- (Sea breeze) wind blowing from the sea. Samoilov K.I. Marine Dictionary. M. L .: State Naval Publishing House of the NKVMF of the USSR, 1941 ... Marine Dictionary

sea ​​wind- jūrinis vėjas statusas T sritis ekologija ir aplinkotyra apibrėžtis Nuo jūros, dažnai su lietumi pučiantis vėjas. atitikmenys: engl. seabreeze; sea ​​wind vok. Seewind, m rus. sea ​​wind, m ... Ekologijos terminų aiskinamasis žodynas

NAUTICAL- MARINE, sea, sea. 1. adj. to the sea. Coast. Sea water. Sea sand. Sea bottom. Sea currents. Nautical chart. Sea channel (see channel in 1 and 2 values). || Occurring, being at sea. Sea wind. Sea rock. Maritime… Dictionary Ushakov

WIND- (Wind) movement of air masses in a horizontal direction, or, in other words, horizontal air currents. Each V. is characterized by two elements: the direction in which the air moves, and the speed with which it ... ... Marine Dictionary

WIND- WIND, wind man. movement, flow, flow, current, air flow. According to its strength, the wind happens: a hurricane, a kavk. bora: storm, storm (usually a thunderstorm and rain are connected with a storm), severe, strong, windstorms: medium, weak, calm wind or breeze, breeze, ... ... Dahl's Explanatory Dictionary

WIND BALLISTIC- (Balistic wind) the value of a fictitious constant wind, the effect of which on the projectile along a given trajectory is the same as the effect of a true variable wind. Samoilov K.I. Marine Dictionary. M. L .: State Naval Publishing House of the NKVMF ... ... Marine Dictionary

Wind of Hope (film)- Wind "Hope" Genre Adventure film Director Stanislav Govorukhin Starring Film company ... Wikipedia

Wind of Hope- Genre adventure film Director Stanislav Govorukhin Scriptwriter Stanislav Govorukhin Boris Lobkov ... Wikipedia

Wind of Hope (film)- Wind "Hope" Genre Adventure film Director Stanislav Govorukhin Starring Film company film studio im. M. Gorky Duration 72 min ... Wikipedia

Books

• The violent wind drives the sail ..., Matveev Alexander Ivanovich, "The violent wind drives the sail" - a new poetry collection by Alexander Matveev is dedicated to the theme of eternal, like life itself, the theme of love. There are no people who would not experience this bright feeling.… Category: Modern Russian poetry Publisher: At the Nikitsky Gate, Buy for 344 rubles
• Sea Wind, R. Leoncavallo, Reprint music edition Leoncavallo, Ruggiero`Brise de mer`. Genres: Pieces; For cello, piano; Scores featuring the cello; scores featuring the piano; For 2 players. We have created specially... Category: Jewelery Publisher:

The wind is one of the most unique natural phenomena. We cannot see it, touch it, but we are able to observe the results of its manifestation, for example, how it slowly or quickly drives clouds and clouds across the sky, with its power tilts the trees to the ground or slightly ruffles the foliage.

Wind concept

What is wind? The definition from the point of view of meteorology is as follows: this is the horizontal movement of layers of air from a zone with high atmospheric pressure to a zone of low pressure, accompanied by a certain speed. This movement occurs because during the day the sun penetrates the Earth's air layer. Some rays, reaching the surface, heat the oceans, seas, rivers, mountains, soil, rocks and stones, which give off heat to the air, thereby heating it as well. For the same amount of time, dark objects absorb more heat and warm up more.

But what does it matter how heat is given off and how quickly? And how does this help us figure out what wind is? The definition is as follows: land heats up faster than water, which means that the air accumulated above it receives heat from it and rises, therefore, Atmosphere pressure falls over this area. With water, everything is exactly the opposite: above it, the air masses are colder and the pressure is higher. As a result, cold air is displaced from the area of ​​high pressure to the area of ​​low pressure, forming a wind. The greater the difference between these pressures, the stronger it is.

Types of winds

Having dealt with what wind is, you need to find out how many of its types exist and how they differ from each other. There are three main groups of winds:

• local;
• permanent;
• regional.

Local winds correspond to their name and blow only in certain areas of our planet. Their appearance is associated with the specifics of local reliefs and temperature changes in relatively short periods of time. These winds are characterized by short duration and diurnal periodicity.

What is a wind of local origin is now clear, but it is also divided into its subspecies:

• A breeze is a light wind that changes direction twice a day. During the day it blows from the sea to the land, and vice versa at night.
• Bora is a high-velocity cold air current that blows from the tops of mountains to valleys or coasts. He is fickle.
• Föhn is a warm and light spring wind.
• Dry wind is a dry wind that prevails in the steppe regions during the warm period of time under anticyclone conditions. He foretells drought.
• Sirocco - rapid southern, southwestern air currents that form in the Sahara.
• What is the khamsin wind? These are dusty, dry and hot air masses that prevail in northeast Africa and the east of the Mediterranean.

Constant winds are those that depend on the total circulation of air. They are stable, uniform, constant and strong. They belong to:

• trade winds - winds from the east, are distinguished by constancy, not changing direction and strength of 3-4 points;
• antitrade winds - winds from the west, carrying huge air masses.

The regional wind appears as a result of pressure drops, a bit like the local one, but more stable and powerful. A prominent representative of this species is the monsoon, which originates in the tropics, at the turn of the ocean. It blows periodically, but in large streams, changing its direction a couple of times a year: in the summer season - from water to land, in winter - vice versa. The monsoon brings a lot of moisture in the form of rain.

Strong wind is...

What is a strong wind and how does it differ from other streams? Its most important feature is high speed, which ranges from 14-32 m/s. It produces devastating actions or brings damage, destruction. In addition to speed, temperature, direction, location and duration also matter.

Types of strong winds

• A typhoon (hurricane) is accompanied by intense precipitation and a drop in temperature, great strength, speed (177 km / h or more), blows at a distance of 20-200 m for several days.
• What is a wind called a squall? This is a sharp, sudden flow at a speed of 72-108 km / h, which is formed during the hot period as a result of the powerful penetration of cold air into warm zones. It blows for a couple of seconds or tens of minutes, changing direction, and brings a decrease in temperature.
• Storm: its speed is 103-120 km/h. Characterized high duration, force. He is the source of strong sea vibrations and destruction on land.

• Tornado (tornado) is an air whirlwind, visually similar to a dark column along which a curved axis passes. At the bottom and top of the column there are expansions similar to a funnel. The air in the vortex rotates counterclockwise at a speed of 300 km / h and draws all nearby objects, objects into its funnel. The pressure inside the tornado is reduced. The column reaches a height of 1500 m, and its diameter is from a dozen (above water) to hundreds of meters (above land). A tornado can travel from a couple of hundred meters to tens of kilometers at a speed of 60 km/h.
• Storm - air mass, the speed of which is in the range of 62-100 km / h. Storms abundantly cover the area with sand, dust, snow, earth, causing harm to people and the economy.

Description of wind power

When answering the question of what wind force is, it would be appropriate to note that here the concept of force is interconnected with speed: the higher it is, the stronger the wind. This indicator is measured on a 13-point Beaufort scale. Zero value characterizes calm, 3 points - light, weak wind, 7 - powerful, 9 - the appearance of a storm, more than nine - merciless storms, hurricanes. Strong winds they often blow over the sea, ocean, because nothing interferes with them here, unlike rocky mountains, hills, forests.

Definition of the solar wind

What is solar wind? it amazing phenomenon. Ionized plasma particles flow out of the solar corona (outer layer) into space with a speed range of 300-1200 km/s, which depends on the activity of the Sun.

There are slow (400 km/s), fast (700 km/s), high-speed (up to 1200 km/s) solar winds. They form an area with space around the central celestial body, which protects solar system from interstellar gas. In addition, thanks to them, such phenomena as the radiation belt and the aurora borealis occur on our planet. That's what the solar wind is.