Wind- motion airrelative to the underlying surface.

Air - a natural mixture of gases (mainly nitrogen and oxygen - 98-99% in total, as well as carbon dioxide, water, hydrogen, etc.) forming the earth's atmosphere.

Windsock - the simplest device for determining the speed and direction of the wind, used at aerodromes

On Earth, wind is a stream of air that moves predominantly in a horizontal direction; on other planets it is a stream of atmospheric gases characteristic of these planets. The strongest winds in the solar system are observed on Neptune and Saturn. The solar wind is the flow of rarefied gases from the star, and the planetary wind is the flow of gases responsible for degassing the planetary atmosphere into outer space. Winds are usually classified according to their magnitude, speed, types of forces that cause them, locations of propagation and impact on the environment.

Winds are classified primarily by their strength, duration and direction. Thus, gusts are considered to be short-term (several seconds) and strong air movements. Strong winds of average duration (about 1 minute) are called squalls. The names of the longer winds depend on the strength, for example, such names are breeze, storm, storm, hurricane, typhoon. The duration of the wind also varies greatly: some thunderstorms can last several minutes, the breeze, which depends on the difference in the heating of the relief features during the day, lasts several hours, global winds caused by seasonal temperature changes - monsoons - have a duration of several months, while the global winds caused by differences in temperature at different latitudes and the Coriolis force blow constantly and are called trade winds. Monsoons and trade winds are winds that make up the general and local circulation of the atmosphere.

Winds have always influenced human civilization, they inspired mythological tales, influenced historical actions, expanded the range of trade, cultural development and war, supplied energy for various mechanisms of energy production and recreation. Thanks to sailing ships that sailed with the wind, for the first time, it became possible to overcome long distances over seas and oceans. Balloons, which were also powered by wind, were the first to allow air travel, and modern aircraft use wind to increase lift and save fuel. However, winds can also be unsafe, as gradient wind fluctuations can cause loss of control over the aircraft, fast winds, as well as large waves caused by them, often lead to the destruction of piece buildings on large bodies of water, and in some cases winds can increase the scale of a fire.

Winds can also affect the formation of relief, causing aeolian depositsthat form different kinds soil (for example, loess) or erosion. They can carry sand and dust from deserts over long distances. The winds carry the seeds of plants and aid the movement of flying animals, which lead to the expansion of species in new territory. Wind-related phenomena affect wildlife in a variety of ways.

Panorama of Aeolian Pillars in Bryce Canyon National Park (Utah)

The wind occurs as a result of uneven distribution of atmospheric pressure and is directed from a high pressure area to a low pressure area. Due to the continuous change in pressure in time and space, the speed and direction of the wind are constantly changing. With height, the wind speed changes due to a decrease in the friction force.

For visual assessment of wind speed beaufort scale. The meteorological direction of the wind is indicated by the azimuth of the point from which the wind is blowing; whereas the aeronautical wind direction is where it is blowing, thus the values \u200b\u200bdiffer by 180 °. Long-term observations of the direction and strength of the wind are depicted in the form of a graph - wind roses.

In some cases, it is not the direction of the wind itself that is important, but the position of the object relative to it. So, when hunting for an animal with a sharp scent, they approach it from the leeward side - in order to avoid the spread of the smell from the hunter towards the animal.

The vertical movement of air is called ascending or downdraft.

General patterns

Wind is caused by the difference in pressure between two different air regions. If there is a nonzero baric gradient (vector characterizing the degree of change in atmospheric pressure in space) , then the wind moves with acceleration from the high pressure zone to the low pressure zone. On a planet that rotates, this gradient is added coriolis force (one of the inertial forces acting on an ordered flow of a liquid or gas in a rotating non-inertial frame of reference ) ... Thus, the main factors that formcirculation of the atmosphere on a global scale, is the difference in air heating andsolar wind betweenequatorial and polar areas that cause a difference intemperature and correspondingly,air flow density, and in turn the difference inpressure (as well as the Coriolis forces). As a result of the action of these factors, the movement of air in the middle latitudes in the near-surface region close to the wind leads to the formationgeostrophic wind (it is a theoretical wind that is the result of a complete balance between the Coriolis force and the baric gradient) and its movement, directed almost parallelisobars (eh then the process occurring at constant pressure) .

An important factor that speaks about the movement of air is its friction against the surface, which delays this movement and forces the air to move towards areas with low pressure. In addition, local barriers and local surface temperature gradients can create local winds. The difference between real and geostrophic wind is called ageostrophic wind... It is responsible for creating chaotic vortex processes such as cyclones and anticyclones ... While the direction of the near-surface in tropical and polar regions is determined mainly by the effects of global atmospheric circulation, which in temperate latitudes usually weak and cyclones together with anticyclones replace each other and change their direction every few days.

Global effects of wind generation

Most areas of the Earth are dominated by winds blowing in a certain direction. Near the poles, easterly winds usually dominate, in temperate latitudes, westerly winds, while in the tropics, easterly winds again dominate. On the boundaries between these belts - the polar front and the subtropical ridge - there are calm zones where the prevailing winds are practically absent. In these zones, air movement is predominantly vertical, which is why zones of high humidity (near the polar front) or deserts (near the subtropical ridge) arise.

Passat

Atmosphere circulation

Atmosphere circulation - a system of closed currents of air masses, manifested on the scale of the hemispheres or the entire globe. Such currents lead to the transfer of matter and energy in the atmosphere in both latitudinal and meridional directions, which is why they are the most important climate-forming process, affecting the weather anywhere on the planet.

Diagram of the global circulation of the atmosphere

The main reason for the circulation of the atmosphere is solar energy and the unevenness of its distribution on the surface of the planet, as a result of which different areas of soil, air and water have different temperatures and, accordingly, different atmospheric pressure (baric gradient). In addition to the Sun, the movement of air is influenced by the rotation of the Earth around its axis and the heterogeneity of its surface, which causes air friction against the soil and its entrainment.

Air currents in their scale vary from tens and hundreds of meters (such movements create local winds) to hundreds and thousands of kilometers, leading to the formation of cyclones, anticyclones, monsoons and trade winds in the troposphere. In the stratosphere, mainly zonal transfers take place (which determines the existence of latitudinal zoning). The global elements of atmospheric circulation are the so-called circulation cells - hadley cell, ferrell cell, polar cell.

Hadley cell Is an element of the circulation of the earth's atmosphere observed in tropical latitudes. It is characterized by an upward movement at the equator, a flow directed toward the pole at an altitude of 10-15 km, a downward movement in the subtropics and a flow toward the equator at the surface. This circulation is directly related to phenomena such as trade winds, subtropical deserts and high-altitude jet currents.

Hadley's cell, one of three atmospheric circulation cells that move heat towards the poles and determine the weather on Earth

The main driving force behind atmospheric circulation is the sun's energy, which on average heats the atmosphere more at the equator and less at the poles. Atmospheric circulation transfers energy towards the poles, thus reducing the temperature gradient between the equator and the poles. The mechanism by which this is implemented differs in tropical and extratropical latitudes.

Between 30 ° N and 30 ° S. this energy transport is realized through a relatively simple cyclic circulation. Air rises at the equator, is carried towards the poles at the tropopause, descends in the subtropics, and returns to the equator at the surface. At high latitudes, energy is transported by cyclones and anticyclones, which move relatively warm air towards the poles, and cold air towards the equator in the same horizontal plane. A tropical circulation cell is called a Hadley cell.

In the tropopause region, as air moves towards the poles, it experiences the Coriolis force, which turns the wind to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, creating a tropical high-altitude jet stream that is directed from west to east. You can imagine it as a ring of air trying to keep its angular momentum in an absolute coordinate system (not rotating with the Earth). When the air ring moves towards the pole, it turns out to be closer to the axis of rotation and must rotate faster, which creates jet currents rotating faster than the Earth itself, which are called jet streams and directed from west to east with respect to the surface. Similarly, at the surface, air returning to the equator rotates westward, or slows down from the point of view of a non-rotating observer as it moves away from the axis of rotation. These near-surface winds are called trade winds.

Ferrell (Ferrel) cell - an element of the circulation of the earth's atmosphere in the temperate zone, is located approximately between 30 and 65 degrees north latitude and 30 and 65 degrees south latitude and is limited by a subtropical ridge on the equatorial side and a polar front on the polar one. The Ferrell cell is considered a minor circulation element and is completely dependent on the Hadley cell and the polar cell. The theory of the existence of this cell was developed by the American meteorologist William Ferrell in 1856.

In fact, the Ferrell cell acts as a rolling bearing between the Hadley cell and the polar cell, which is why it is sometimes called the mixing zone. At the circumpolar boundary, the Ferrell cell may overlap with the polar cell, and at the equatorial boundary, with the Hadley cell. The prevailing near-surface winds that correspond to this cell are called westerly winds of the temperate zone. However, local effects easily change the cell: for example, the Asian anticyclone significantly shifts it to the south, actually making it discontinuous.

While the Hadley cell and the polar cell are closed, the Ferrell cell is not necessarily such, with the result that the westerly winds of temperate latitudes are not as regular as the trade winds or easterly winds of the polar regions, and depend on local conditions. Although the high-altitude winds are indeed westerly, the near-surface winds often and sharply change their direction. The lack of rapid movement to the poles or to the equator does not allow these winds to accelerate, as a result, when a cyclone or anticyclone passes, the wind can quickly change direction, and during days blow in an easterly or other direction.

The location of the cell strongly depends on the location of the corresponding high-altitude jet stream, which determines the location of the strip of near-surface cyclones. Although the total air movement at the surface is limited to about 30 and 65 degrees north and south latitudes, the vertical air return is much less pronounced.

Polar cell, or polar vortex - an element of the circulation of the Earth's atmosphere in the circumpolar regions of the Earth, has the form of a near-surface vortex, which swirls to the west, leaving the poles; and a high-rise vortex swirling to the east.

This is a fairly simple circulation system driven by the difference in heating of the earth's surface at the poles and at temperate latitudes. Although the air around the polar front is about 60 degrees north and south, the air is cooler and drier than in the tropics, it is still warm enough to generate convection. Air circulation is limited by the troposphere, that is, by the layer from the surface to an altitude of about 8 km. Warm air rises at low latitudes and moves towards the poles in the upper troposphere. Reaching the poles, the air cools and descends, forming a high pressure zone - a polar anticyclone.

Near-surface air moves between the high-pressure zone of the polar anticyclone and the low-pressure zone of the polar front, deviating to the west under the action of the Coriolis force, as a result of which east winds are formed near the surface - east winds of the polar regions, surrounding the pole in the form of a vortex.

The airflow from the poles forms very long waves - Rossby waves, which play an important role in determining the path of the high-altitude jet stream in the upper part of the Ferrell cell, a circulation cell that is located at low latitudes.

Prevailing winds

Prevailing or prevailing winds - winds that blow mainly in one direction over a specific point on the earth's surface. They are part of the global picture of air circulation in the Earth's atmosphere, including trade winds, monsoons, westerly winds of the temperate belt and easterly winds of the polar regions. In areas where global winds are weak, prevailing winds are determined by breeze directions and other local factors. In addition, global winds can deviate from typical directions depending on the presence of obstacles.

The influence of the prevailing wind on conifer tree in western Turkey

To determine the direction of the prevailing wind, use wind rose. Knowing the direction of the wind allows you to develop a plan to protect farmland from soil erosion.

Sand dunes in coastal and desert locations can be oriented along or perpendicular to the direction of constant wind. Insects drift with the wind, and birds can fly regardless of the prevailing wind. Prevailing winds in mountainous areas can lead to significant differences in precipitation on upwind (wet) and leeward (dry) slopes.

wind rose- graphic representation of the frequency of winds in each direction in a given area, built in the form of a histogram in polar coordinates. Each dash in the circle indicates the frequency of the winds in a specific direction, and each concentric circle corresponds to a specific frequency. The wind rose can contain additional information, for example, each dash can be colored in different colors corresponding to a certain range of wind speed. Wind roses often have 8 or 16 dashes corresponding to the main directions, that is, north (N), northwest (NW), west (W), etc., or N, NNW, NW, NWW, W, etc. sometimes the number of dashes is 32. If the frequency of the wind in a certain direction or range of directions significantly exceeds the frequency of the wind in other directions, it is said that there are prevailing winds in that area.

Windrose at Fresno Yosemite International Airport, California, 1961-1990

Wind rose - a diagram that characterizes in meteorology and climatology, the wind regime in a given place according to long-term observations and looks like a polygon, in which the lengths of the rays diverging from the center of the diagram in different directions (horizon points) are proportional to the frequency of the winds in these directions ("from where" wind blows). The wind rose is taken into account in the construction of runways of airfields, highways, planning of populated areas (appropriate orientation of buildings and streets), assessment of the relative position of the residential area and the industrial zone (in terms of the direction of transport of impurities from the industrial zone) and many other economic tasks (agronomy, forestry and park economy, ecology, etc.).

The wind rose, built on the basis of real observation data, allows you to identify the direction along the length of the rays of the constructed polygon dominant, or prevailing wind, from which the air flow most often comes to a given area. Therefore, a real wind rose, built on the basis of a number of observations, may have significant differences in the lengths of different rays. What is traditionally called the "wind rose" in heraldry - with a uniform and regular distribution of rays along the azimuths of the cardinal points at a given point - is just a geographical designation of the main geographic azimuths of the sides of the horizon in the form of rays.

Examples of different views

In addition to the direction of the wind, the wind rose can demonstrate the frequency of the winds (sampled according to a certain criterion - per day, per month, per year), as well as the strength of the wind, the duration of the wind (minutes per day, minutes per hour). Moreover, wind roses can exist both to indicate average values \u200b\u200band to indicate maximum values. It is also possible to create a complex wind rose, on which diagrams of two or more parameters will be present. The examples below show different ways to read the diagrams:

Eight-pointed wind rose

This implies the same location of the cardinal points as on the compass. A point is marked on each of the rays, the distance from which to the center is (on a certain agreed scale) the number of days in the past month when the wind of this direction prevailed. The points on the rays are connected to each other and the resulting polygon is shaded.

16-point compass rose

The cardinal points are indicated by letters. Each of the 16 rays, characterizing one direction or another, is depicted as a segment on which the average speed for each wind direction for the past day is marked on a scale.

360-ray compass rose

Image automatically generated by the meteorological program based on instrument readings. The diagram shows graphically the maximum wind speed for the reporting period.

Compass rose with numerical values \u200b\u200band additional markings

On each of the rays, the length of the segment is duplicated as a numerical value that describes the number of days in a certain period when the wind of a given direction prevailed. The signs at the ends of the segments indicate the maximum wind speed. The number in the center of the chart represents the number of calm days. Judging by the diagram, it can be judged that the period was 90 days, of which 8 days were calm, 70 days were marked on the directions with numbers, the remaining 12 days and two directions, apparently, were considered insignificant and were not marked with numbers.

Tropical winds

The trade winds are called the near-surface part of the Hadley cell - the prevailing near-surface winds blowing in the tropical regions of the Earth in a westerly direction, approaching the equator, that is, northeastern winds in the Northern Hemisphere and southeastern winds in the South. The constant movement of trade winds leads to mixing of the Earth's air masses, which can manifest itself on a very large scale: for example, trade winds blowing over the Atlantic Ocean are capable of transporting dust from the African deserts to the West Indies and some areas North America.

Circulation processes of the Earth that lead to wind generation

Monsoons are the predominant seasonal winds that blow in tropical areas for several months each year. The term originated in British India and surrounding countries as a name for seasonal winds that blow from the Indian Ocean and the Arabian Sea to the northeast, bringing significant rainfall to the region. Their movement towards the poles is caused by the formation of low pressure areas as a result of the heating of tropical regions in the summer months, that is, Asia, Africa and North America from May to July, and Australia in December.

Trade winds and monsoons are the main factors that lead to the formation of tropical cyclones over the oceans of the Earth.

Passat (from the Spanish viento de pasada - wind favorable to moving, movement) - the wind blowing between the tropics all year round, in the Northern Hemisphere from the northeast, in the Southern Hemisphere from the southeast, separating from each other by a windless strip. On the oceans, trade winds blow with the greatest accuracy; on the continents and on the seas adjacent to the latter, their direction is partly modified under the influence of local conditions. In the Indian Ocean, due to the configuration of the coastal continent, the trade winds completely change their character and turn into monsoons.

Wind map over the Atlantic

Due to their constancy and strength in the era of the sailing fleet, the trade winds, along with the westerly winds, were the main factor in the construction of routes for ships in communication between Europe and the New World.

As a result of the action of the sun's rays in the equatorial zone, the lower layers of the atmosphere, warming up more strongly, rise upward and tend towards the poles, while new colder air currents from the north and south come below; due to the diurnal rotation of the Earth, according to the Coriolis force, these air currents in the Northern Hemisphere take a direction towards the southwest (northeast trade wind), and in the Southern Hemisphere - northwest direction (southeast trade wind). The closer any point on the globe lies to the pole, the smaller the circle it describes in a day, and, consequently, the less speed it acquires; thus, air masses flowing from higher latitudes, having a lower velocity than points on the earth's surface on the equatorial strip, rotating from west to east, should lag behind them and, therefore, give a current from east to west. At low latitudes, close to the equator, the difference in velocities for one degree is very insignificant, since the meridian arcs become almost mutually parallel, and therefore in the strip between 10 ° N. and 10 ° S. the inflowing layers of air, in contact with the earth's surface, acquire the speed of the points of the latter; as a result, near the equator, the northeastern trade wind again takes an almost northerly direction, and the southeast trade wind is almost southerly and, mutually meeting, give a strip of calm. In the strip of trade winds between 30 ° N lat. and 30 ° S in each hemisphere, two trade winds blow: in the Northern Hemisphere at the bottom northeast, at the top southwest, in the South at the bottom - southeast, at the top of the northwest. The upstream is called anti-passat, counterpass, or upper trade wind... Beyond 30 ° north and south latitude. the upper, coming from the equator, air layers descend to the earth's surface and the correctness of the equatorial and polar currents stops. From the polar border of the trade wind (30 °), part of the air mass returns to the equator as the lower trade wind, while the other part flows to higher latitudes and appears in the Northern Hemisphere as a southwestern or westerly wind, and in the South - as a northwestern or westerly wind ...

When relatively cold air masses from temperate latitudes enter the subtropics, the air heats up and the development of powerful convective currents (rise in air masses) with a rise rate of 4 meters per second. Cumulus clouds are forming. At an altitude of 1200-2000 m, a retarding layer is formed: isothermal (the temperature does not change with height) or inversion (the temperature increases with height). It delays the development of cloudiness, so there is very little precipitation. Small droplet rains occur only occasionally.

Lower trade winds between the tropics; on the Atlantic and Pacific oceans, were known to sailors of antiquity. Columbus's satellites were greatly alarmed by these winds, which carried them non-stop westward. The correct explanation of the origin of the trade wind was first given by the English astronomer John Hadley (1735). The strip of calm moves north or south, depending on the state of the sun at the equator; in the same way, the borders of the trade wind area change both in the north and in the south at different times of the year. In the Atlantic Ocean, the northeastern trade wind blows in winter and spring between 5 ° and 27 ° N, and in summer and autumn between 10 ° and 30 ° N. The southeastern trade wind reaches 2 ° N in winter and spring, and 3 ° N in summer and autumn, thus crossing the equator and gradually turning into a south and south-west wind. The region of calm between the trade winds in the Atlantic Ocean lies north of the equator and is 150 nautical miles wide in December and January, and 550 miles in September. In the Pacific, the equatorial boundaries of the trade wind region are less variable than in the Atlantic; the northeastern trade wind in the Pacific Ocean reaches only 25 ° N, and in the Atlantic 28 ° N. In general, the southeastern trade wind is stronger than the northeastern trade wind: it does not encounter any obstacles in vast bodies of water, and this explains the fact that it enters the northern hemisphere.

Monsoon (from Arabic موسم ("māvsim") - the season, through the French mousson) - steady winds that periodically change their direction; in summer they blow from the ocean, in winter - from land; characteristic of tropical regions and some coastal countries of the temperate zone ( Far East). The monsoon climate is characterized by high humidity during the summer.

In each location of the monsoon region, during each of the two main seasons, there is a wind regime with a pronounced predominance of one direction over the others. Moreover, in another season, the prevailing wind direction will be opposite or close to opposite. Thus, in each monsoon region, there are summer and winter monsoons with mutually opposite or at least sharply different prevailing directions.

Of course, besides the prevailing winds, winds from other directions are also observed in each season: the monsoon is intermittent. During the transitional seasons, in spring and autumn, when the monsoons change, the stability of the wind regime is disturbed.

The stability of monsoons is associated with a stable distribution of atmospheric pressure during each season, and their seasonal change - with radical changes in the distribution of pressure from season to season. The prevailing baric gradients sharply change direction from season to season, along with this, the wind direction also changes.

In the case of monsoons, as in the case of trade winds, the stability of the distribution does not at all mean that the same anticyclone or the same depression is held over a given area during the season. For example, in winter over East Asia a number of anticyclones are successively replaced. But each of these anticyclones persists for a relatively long time, and the number of days with anticyclones significantly exceeds the number of days with cyclones. As a result, an anticyclone is also obtained on a long-term average climatic map. The northern wind directions associated with the eastern periphery of the anticyclones prevail over all other wind directions; That's what it is winter east asian monsoon... So, monsoons are observed in those areas where cyclones and anticyclones have sufficient stability and a sharp seasonal prevalence of some over others. In the same areas of the Earth, where cyclones and anticyclones quickly replace each other and slightly dominate one over the other, the wind regime is changeable and does not resemble the monsoon. This is the case in most of Europe.

In summer, monsoons blow from the ocean to the continents, in winter - from the continents to the oceans; characteristic of tropical regions and some coastal countries of the temperate zone (for example, the Far East). The monsoons are most stable and wind speed in some areas of the tropics (especially in equatorial Africa, the countries of South and Southeast Asia and in the Southern Hemisphere up to the northern parts of Madagascar and Australia). In a weaker form and in limited areas, monsoons are also found in subtropical latitudes (in particular, in the south Mediterranean Sea and in North Africa, in the Gulf of Mexico, in East Asia, in South America, in southern Africa and Australia).

Above the ridge. Vindhya (India)

Kolkata (India)

Arizona (USA)

Darwin (Australia)

Westerly winds of the temperate zone - prevailing winds blowing in the temperate zone between about 35 and 65 degrees north and south latitude, from the subtropical ridge to the polar front, part of the global atmospheric circulation processes and the near-surface part of the Ferrell cell. These winds blow mainly from west to east, more precisely from the southwest in the Northern Hemisphere and from the northwest in the Southern Hemisphere, and can form extratropical cyclones at their borders, where the wind speed gradient is high. Tropical cyclones that penetrate the zone of these winds through the subtropical ridge, losing strength, are reinforced again due to the speed gradient of the westerly winds of the temperate zone.

Map of the trade winds and westerly winds of the temperate zone

Westerly winds from the temperate zone blow stronger in winter, when the pressure above the poles is lower, and weak in summer. These winds are strongest in the Southern Hemisphere, where there is less land mass, which tends to deflect or delay the wind. The belt of strong westerly winds in the temperate zone is located between 40 and 50 degrees south latitude and is known as the "Roaring Forties." These winds play an important role in the formation of ocean currents that carry warm equatorial waters to the western shores of continents, especially in the Southern Hemisphere.

Benjamin Franklin's map of the Gulf Stream

East winds polar regions, the near-surface part of the polar cells, are mainly dry winds blowing from the subpolar high-pressure zones to low-pressure areas along the polar front.

These winds are usually weaker and less regular than the westerly winds of the temperate latitudes. Due to the small amount of solar heat, the air in the polar regions cools and sinks downward, forming high pressure areas and pushing the circumpolar air towards lower latitudes. This air, as a result of the Coriolis force, is deflected westward, forming northeasterly winds in the Northern Hemisphere and southeasterly in the South.

Local effects of wind generationarise depending on the presence of local geographic objects. One of these effects is the temperature difference between not very distant areas, which can be caused by different coefficients of absorption of sunlight or different heat capacity of the surface. The latter effect is most pronounced between land and water surface and causes breezes. Another important local factor is the presence of mountains, which act as a barrier to the winds.

The most important local winds on Earth

Local winds - winds that differ in any way from the main character of the general circulation of the atmosphere, but, like constant winds, regularly recurring and having a noticeable effect on the weather regime in a limited part of the landscape or water area.

Local winds include breeze, changing its direction twice a day, mountain-valley winds, bora, hair dryer, dry wind, samum and many others.

The occurrence of local winds is mainly associated with the difference in temperature conditions over large bodies of water (breezes) or mountains, their strike relative to the general circulation flows and the location of mountain valleys (fen, bora, mountain-valley), as well as with changes in the general atmospheric circulation by local conditions (samum , sirocco, hamsin). Some of them are essentially air currents of the general circulation of the atmosphere, but in a certain area they have special properties, and therefore they are referred to local winds and give them their own names.

For example, only on Lake Baikal, due to the difference in the warming of water and land and the complex location of steep ridges with deep valleys, at least 5 local winds are distinguished: barguzin - a warm north-east, mountain - north-west wind, causing powerful storms, Sarma - a sudden west wind, reaching hurricane force up to 80 m / s, valley - southwestern kultuk and southeastern shelonik.

Afghan

Afghan - dry, baking local wind, with dust, which blows in Central Asia. It has a southwestern character and blows in the upper reaches of the Amu Darya. It blows from several days to several weeks. Early spring with showers. Very aggressive. In Afghanistan it is called kara-Buranwhich means black storm or body shuravi - soviet wind.

Biza

Bise - cold and dry north or north-east wind in the mountainous regions of France and Switzerland. Bizet is similar to bora.

Bora

Bora (ital. bora, from the Greek. βορέας - north wind; "Borey" - cold north wind) - a strong cold gusty local wind that occurs when the flow of cold air meets a hill on its way; overcoming the obstacle, the bora falls down on the coast with great force. The vertical dimensions of the bora are several hundred meters. Affects, as a rule, small areas where low mountains directly border the sea.

Bora origin diagram

Particularly strong in Russia are the pine forests of Novorossiysk Bay and Gelendzhik Bay (where they have a northeastern direction and blow more than 40 days a year), Novaya Zemlya, the shores of Lake Baikal (Sarma near the Olkhonskiye Vorota Strait), the Chukotka town of Pevek (the so-called Yuzhak ).

The consequences of the bora, Novorossiysk, November 11, 1993

Ship-wreck as a result of bora, Novorossiysk, 1993

Novorossiysk, 1997

In Europe, the most famous forests of the Adriatic Sea (in the area of \u200b\u200bthe cities of Trieste, Rijeka, Zadar, Senj, etc.). In Croatia, the wind is called borax... Similar to bora and wind "nord" in the Baku region, mistral on the Mediterranean coast of France from Montpellier to Toulon, "northser" in the Gulf of Mexico. Bora lasts from a day to a week. The daily temperature difference during bora can reach 40 ° C.

Bora

Bora arises in Novorossiysk and the Adriatic coast in those cases when the cold front approaches the coastal ridge from the northeast. The cold front immediately passes over a low ridge. Under the influence of gravity, cold air is thrown down the ridge, while gaining great speed.

Before the emergence of the bora at the tops of the mountains, one can observe thick clouds, which the residents of Novorossiysk call "beard"... Initially, the wind is extremely unstable, changing direction and strength, but gradually acquires a certain direction and tremendous speed - up to 60 m / s on the Markotkh pass near Novorossiysk. In 1928, a wind gust of 80 m / s was recorded. On average, the wind speed in bora reaches more than 20 m / s in the Novorossiysk region in winter. Falling to the surface of the water, this downdraft causes a stormy wind, causing severe rough seas. At the same time, the air temperature sharply decreases, which before the beginning of the bora was rather high over the warm sea.

Sometimes bora causes significant destruction in the coastal zone (for example, in Novorossiysk in 2002, bora caused the death of several dozen people); at sea, the wind contributes to strong waves; increased waves flood the shores and also bring destruction; during severe frosts (in Novorossiysk about −20 ... −24 ° C), they freeze, and an ice crust forms (on the Adriatic, the only place where an ice crust forms is the city of Senj). Sometimes the bora is felt far from the coast (on the Black Sea it is 10-15 kilometers deep into the sea, on the Adriatic, at some synoptic positions, it covers a significant part of the sea).

Bora varieties are tramontana, sarma.

Tramontana (ital. tramontana - "from behind the mountains" ) - cold north and north-east winds in Italy, Spain, France and Croatia. It is a type of Bora wind. It arises from the difference between high pressure in mainland Europe and low pressure in the Mediterranean Sea. Tramontana can reach speeds of up to 130 km / h.

Tramontana clouds, southern France

The form of the name differs slightly in each country. IN english language came from Italian (tramontana), which, in turn, is a modified Latin word trānsmontānus (trāns- + montānus). In Catalonia and Croatia, the wind is called Tramuntana. In Spain, on the island of Mallorca, there is the Serra de Tramuntana mountainous region. Serra de Tramuntana (Serra de Tramuntana) - Catalan version, Sierra de Tramontana (Sierra de Tramontana) - Spanish version of the name of these mountains. In Croatia, Tramontana is the name for the northern tip of the island of Cres.

Breeze

Breeze (fr. brise) - the wind that blows on the coast of the seas and large lakes. The direction of the breeze changes twice a day: the day (or sea) breeze blows from the sea to the coast warmed by the daytime rays of the Sun. The night (or coastal) breeze is reversed.

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

The breeze speed is low, 1–5 m / s, rarely more. The breeze is noticeable only under conditions of weak general air transport, usually in the tropics, and in mid-latitudes - in stable calm weather. The vertical height (thickness) of the air layer is up to 1–2 km during the day and somewhat less at night. At higher altitudes, there is reverse flow — anti-breeze. Breeze circulation affects coastal and sea areas 10-50 km wide. The sea breeze lowers the air temperature during the daytime and makes the air more humid. The breeze is more common in summer, when the temperature difference between land and water reaches the greatest values.

Garmsil

Garmsil (taj. Garmsel ) - dry and hot wind type hair dryer, blowing mainly in summer from the south and southeast in the foothills of the Kopetdag and Western Tien Shan.

Fyong (it. Föhn, from lat. favonius - the Roman equivalent of Zephyr) is a strong, gusty, warm and dry local wind blowing from the mountains to the valleys.

Cold air from high mountains quickly descends down the relatively narrow intermountain valleys, which leads to its adiabatic heating. For every 100 m lowering, the air heats up by about 1 ° C. Descending from a height of 2500 m, it heats up by 25 degrees and becomes warm, even hot. Usually, a hair dryer lasts less than a day, but sometimes the duration reaches 5 days, and changes in temperature and relative humidity can be rapid and abrupt.

Hair dryers are especially frequent in spring, when the intensity of the general circulation of air masses sharply increases. Unlike a hair dryer, boron is formed when masses of dense cold air invade.

The name of this wind has become a household name for a household electrical hair dryer - a hair dryer. The word entered our speech in a slightly distorted form due to the inaccurate transliteration of the German trademark Fön, under which these electrical appliances were produced since 1908.

(To be continued)

Atmospheric pressure and its measurements

The air surrounding the Earth has a mass, and therefore presses on the earth's surface. 1 liter of air at sea level weighs about 1.3 g. Consequently, for every square centimeter of the earth's surface, the atmosphere presses with a force of 1.33 kg. This average air pressure at sea level, corresponding to the mass of a 760 mm high mercury column with a cross section of 1 cm2, is taken as normal. Air pressure is also measured in millibars: 1 mm of pressure is 1.33 mbar. So, to convert millimeters to millibars, you need to multiply the millimeter of pressure by 1.33.

The pressure value changes with air temperature and altitude. Since air expands when heated and contracts when cooled, warm air is lighter (causes less pressure) than cold air. As the air rises upward, the pressure decreases mainly because the height of its column is less per unit area. Therefore, in high mountains, the pressure is much less than at sea level. The vertical segment through which the atmospheric pressure decreases by one is called the baric degree. In the lower atmosphere at the surface, the pressure decreases by about 10 mm for every 100 m of rise.

A mercury column barometer is used to measure pressure, and in field conditions - metal aneroid barometer. The latter is a metal box from which air is pumped out. With an increase in atmospheric pressure, the bottom of the capsule contracts, and with a decrease, it unbends. These changes are transferred to the arrow, moving on a circular scale.

Winds and their origin

Zoning also appears in the pressure distribution on the earth's surface. The general planetary scheme of pressure distribution is as follows: a belt of reduced pressure extends along the equator; to the north and south of it at the C-40's latitudes there are high pressure belts, further at 60-70 ° N. and y. sh. - Low pressure belts, in the polar regions - areas of high pressure. Real distribution picture

pressure is much more complex, which is reflected in the maps of the July and January isobars).

The uneven distribution of pressure across the globe causes air to move from an area of \u200b\u200bincreased pressure to an area of \u200b\u200breduced pressure. This movement of air in the horizontal direction is called the wind. The greater the pressure difference, the stronger the wind blows. Wind strength is rated from 0 to 12 points.

The direction of the wind is determined by the side of the horizon from which it blows. The wind changes with changes in pressure. The rotation of the Earth around its axis also has a significant influence on its direction.

General circulation of the atmosphere. Trade winds and other constant winds

Winds observed over the earth's surface are divided into three groups: local winds caused by local conditions (temperature, relief features); winds of cyclones and anticyclones; winds are part of the general circulation of the atmosphere. The general circulation of the atmosphere is formed by the largest air currents of a planetary scale, covering the entire troposphere and the lower stratosphere (up to about 20 km) and are characterized by relative stability. In the troposphere, these include trade winds, westerly winds of temperate latitudes and easterly winds of the polar regions, monsoons. The reason for these planetary air movements is the pressure difference.

A low pressure belt is formed above the equator due to the fact that the air here is warm throughout the year and it mainly rises (the ascending air movement dominates). In the upper troposphere, it cools and spreads towards high latitudes. The Coriolis force, by deflecting air currents in the upper troposphere from the equator, provides them at 30 latitudes western direction, forcing to move only along the parallels. Therefore, this cooled air undergoes a downward movement here, causing high pressure (although the air temperature is even higher at the surface than at the equator). These subtropical high-pressure belts serve as the main "vitrorodilamas on Earth. From them the air volumes of the lower troposphere are directed both to the equator and towards the temperate latitudes.

Winds, characterized by stability of direction and speed, blow throughout the year from high-pressure belts (25-35 ° N and S. Sh.) To the equator are called trade winds. Due to the rotation of the Earth around its axis, they deviate from the previous direction, in the Northern Hemisphere they blow from northeast to southwest, and in the South - from southeast to northwest.

Winds blowing from the subtropical high-pressure belts towards the poles, deviating to the right or left, depending on the hemisphere, change their direction to the west. Therefore, in temperate latitudes, westerly winds prevail, although they did not become as good as the trade winds.

Constant winds also blow from areas of high pressure in polar latitudes towards temperate latitudes with relatively low pressure. Experiencing the action of the forces of rotation, they are northeastern in the Northern Hemisphere, and southeastern in the South.

In temperate latitudes, where warm air masses meet from the tropics and cold air masses from the polar regions, frontal cyclones and anticyclones constantly arise, in which air is transported from west to east.

Prevailing winds - winds that blow mainly in one direction over a specific point on the earth's surface. They are part of the global picture of air circulation in the Earth's atmosphere, including trade winds, monsoons, westerly winds of the temperate belt and easterly winds of the polar regions. In areas where global winds are weak, prevailing winds are determined by breeze directions and other local factors. In addition, global winds can deviate from typical directions depending on the presence of obstacles.

The wind rose is used to determine the direction of the prevailing wind. Knowing the direction of the wind allows you to develop a plan to protect farmland from soil erosion.

Wind rose is a graphical representation of the frequency of winds in each direction in a given area, built in the form of a histogram in polar coordinates. Each dash in the circle indicates the frequency of the winds in a specific direction, and each concentric circle corresponds to a specific frequency. The wind rose can contain additional information, for example, each dash can be colored in different colors corresponding to a certain range of wind speed. Wind roses often have 8 or 16 dashes corresponding to the main directions, that is, north (N), northwest (NW), west (W), etc., or N, NNW, NW, NWW, W, etc. sometimes the number of dashes is 32. If the frequency of the wind in a certain direction or range of directions significantly exceeds the frequency of the wind in other directions, it is said that there are prevailing winds in that area.

Climatology

Trade winds and their influence

Westerly winds of the temperate zone and their influence

Westerly temperate winds blow in mid-latitudes between 35 and 65 degrees north or south latitude, from west to east north of the high pressure region, directing extratropical cyclones in the appropriate direction. Moreover, they blow stronger in winter, when the pressure above the poles is lower, and weaker in summer.

Westerly winds lead to the development of strong ocean currents in both hemispheres, but especially powerful in the southern hemisphere, where there is less land in the middle latitudes. Westerly winds play an important role in the transport of warm equatorial waters and air masses to the western coasts of continents, especially in the southern hemisphere due to the prevalence of oceanic space.

Eastern winds of the polar regions

Main article: East winds of the polar regions

The easterly polar winds are dry, cold winds blowing from high-pressure polar regions to lower latitudes. Unlike trade winds and westerly winds, they blow from east to west and are often weak and irregular. Due to the low angle of incidence of the sun's rays, cold air accumulates and settles, creating high pressure areas, pushing the air towards the equator; this flow is deflected westward by the Coriolis effect.

Local influence

Sea breeze

In areas where there are no strong air currents, the breeze is an important factor in the formation of the prevailing winds. During the day, the sea warms up to a deeper depth than land, since the water has a greater specific heat , but much slower than the surface of the earth. The temperature of the earth's surface rises and the air above it heats up. Warm air is less dense and therefore rises upward. This rise lowers the air pressure above the ground by about 0.2% (at sea level). The higher-pressure cold air above the sea flows towards the lower-pressure land, creating a cool breeze near the coast.

The strength of the sea breeze is directly proportional to the temperature difference between land and sea. At night, the land cools faster than the ocean - also due to differences in their heat capacity. As soon as the land temperature drops below sea temperature, there is a night breeze - blowing from land to sea.

Winds in mountainous areas

In areas with uneven relief, the natural direction of the wind can change significantly. In mountainous areas, airflow distortions are more severe. Strong ascending and descending currents and vortices arise over hills and valleys. If there is a narrow passage in a mountain range, the wind rushes through it with an increased speed, according to the Bernoulli principle. At some distance from the downdraft air current, the air can remain unstable and turbulent, which poses a particular danger to aircraft taking off and landing.

As a result of the heating and cooling of hilly slopes, air currents similar to sea breezes can appear during the day. The hillsides cool down at night. The air above them becomes colder, heavier and sinks into the valley under the influence of gravity. This wind is called mountain breeze or katabatic wind. If the slopes are covered with snow and ice, the runoff wind will blow into the lowlands throughout the day. Hillsides that are not covered with snow will heat up during the day. Ascending air currents are then formed from the colder valley.

Impact on precipitation

Prevailing winds have a significant impact on the distribution of precipitation near obstacles, such as mountains, that the wind must overcome. On the windward side of the mountains, orographic precipitation falls due to the rise of air upward and its adiabatic cooling, as a result of which the moisture contained in it condenses and falls out in the form of precipitation. On the other hand, on the leeward side of the mountains, the air sinks and heats up, thus reducing the relative humidity and the likelihood of precipitation, forming rain shadow ... As a result, in mountainous areas with prevailing winds, the windward side of the mountains is usually characterized by a humid climate, and the leeward side is arid.

Influence on nature

The prevailing winds also affect wildlife, for example, they carry insects, while birds are able to fight the wind and stay on their course. As a result, prevailing winds determine the direction of insect migration. Another effect of wind on nature is erosion. To protect against such erosion, wind barriers are often built in the form of embankments, forest shelters and other obstacles oriented perpendicular to the direction of the prevailing winds to increase efficiency. The prevailing winds also lead to the formation of dunes in desert areas, which can be oriented either perpendicular or parallel to the direction of the winds.

Notes

1. URS (2008). Section 3.2 Climate conditions (in Spanish). Estudio de Impacto Ambiental Subterráneo de Gas Natural Castor. Retrieved on 2009-04-26.
2. Wind rose. Archived March 15, 2012 at the Wayback Machine American Meteorological Society. Retrieved on 2009-04-25.
3. Jan Curtis (2007). Wind Rose Data. Natural Resources Conservation Service. Retrieved on 2009-04-26.
4. Glossary of Meteorology. trade winds (unspecified) (unavailable link). Glossary of Meteorology... American Meteorological Society (2009). Retrieved September 8, 2008. Archived August 22, 2011.
5. Ralph Stockman Tarr and Frank Morton McMurry (1909). W.W. Shannon, State Printing, pp. 246. Retrieved on 2009-04-15.
6. Joint Typhoon Warning Center (2006). 3.3 JTWC Forecasting Philosophies. United States Navy. Retrieved on 2007-02-11.
7. Science Daily (1999-07-14). African Dust Called A Major Factor Affecting Southeast U.S. Air Quality. Retrieved on 2007-06-10.
8. Glossary of Meteorology. Westerlies (unspecified) (unavailable link)... American Meteorological Society (2009). Retrieved April 15, 2009. Archived August 22, 2011.
9. Sue Ferguson. Climatology of the Interior Columbia River Basin (unspecified) (unavailable link)... Interior Columbia Basin Ecosystem Management Project.7 September 2001. Retrieved September 12, 2009. Archived August 22, 2011.
10. Halldór Björnsson (2005). Global circulation. Archived June 22, 2012. Veðurstofu Íslands. Retrieved on 2008-06-15.
11. Barbie Bischof, Arthur J. Mariano, Edward H. Ryan. The North Atlantic Drift Current (unspecified) ... The National Oceanographic Partnership Program (2003). Retrieved September 10, 2008. Archived August 22, 2011.
12. Erik A. Rasmussen, John Turner. Polar Lows. - Cambridge University Press, 2003. - P. 68.
13. Glossary of Meteorology (2009).

CONSTANT WIND - a wind that retains its direction and speed over time, if within two minutes its direction changes by no more than one point. Distinguish winds of different constancy: by speed - even, gusty (by spirits), squally (naked); in the direction - constant (trade wind, strip,) or unstable, changing, transitional (changeable, wobbly) and vortex, circular (vortex,).

Dictionary of the Winds. - Leningrad: Gidrometeoizdat... L.Z. Proh. 1983.

See what "CONSTANT WIND" is in other dictionaries:

WIND - WIND, wind husband. movement, flow, leakage, current, air flow. According to its strength, the wind is: hurricane, kavk. bora: storm, storm (usually thunderstorm and rain are combined with a storm), violent, strong, winds: medium, weak, quiet wind or breeze, breeze, ... ... Dahl's Explanatory Dictionary

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

Constant wind blowing without interruption for several days and nights on the lake. Seliger. Wed Married wind ... Dictionary of winds

sunny wind - This term has other meanings, see Solar wind (film) ... Wikipedia

SUNNY WIND - constant radial flow of solar plasma. corona in the interplanetary pr in. The flow of energy coming from the interior of the Sun heats the corona plasma to 1.5-2 million K. Constant. heating is not balanced by the loss of energy due to radiation, since the corona density is low. ... ... Physical encyclopedia

sunny wind - is a constant radial outflow of the solar corona plasma (see. Solar corona) into interplanetary space. S.'s education. associated with the flow of energy entering the corona from the deeper layers of the sun. Apparently ... ... Great Soviet Encyclopedia

Conditional (calculated, fictitious) wind, constant over the entire trajectory of a projectile, missile or other object. It has the same effect on flight as the actual wind (changing along the trajectory). B. in. simplifies calculations of wind action ... Dictionary of winds

SUPPLY - where to stand sometimes, at times, quite often. We stand at the gate, look at the passers-by. Wait and wait. Stand, stand for several times in different meanings. I stood at matins, and my legs ached. The ship stood at anchor and left. The regiment stood at ... ... Dahl's Explanatory Dictionary

Sea currents * - The translational movement of waters in the oceans and seas is called a current. The currents are subdivided, in 1 x, into constant, periodic and random, or irregular; in 2 x, on surface and underwater and, in 3 x, on warm and cold. Constant currents do not ... ...

Sea currents - … Encyclopedic Dictionary of F.A. Brockhaus and I.A. Efron

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The air masses surrounding us are in continuous motion: up and down, horizontally. We call the horizontal movement of air the wind. Wind flows are formed according to their own specific laws. To characterize them, indicators such as speed, strength and direction are used.

The winds of different climatic regions have their own features and characteristics. Moderate latitudes of the Northern and Southern Hemispheres are blown by westerly winds.

Constants and variables

The direction of the wind is determined by areas of high and low pressure. Air masses move from high pressure areas to low pressure areas. The direction of the wind also depends on the action of the earth's rotation: in the northern hemisphere, the currents are adjusted to the right, in the southern - to the left. Air flows can be either constant or variable.

Westerly winds of temperate latitudes, trade winds, northeast and southeast belong to the group of permanent ones. If the trade winds are called the winds of the tropics (30 o N - 30 o S), then westerly winds prevail in temperate latitudes from 30 o to 60 o in both hemispheres. In the Northern Hemisphere, these air currents deviate to the right.

In addition to constant ones, there are variable or seasonal winds - breezes and monsoons, as well as local ones, characteristic only for a particular region.

Current of the West Winds

Air, moving in a certain direction, has the ability to carry huge masses of water in the ocean, creating strong currents - rivers among the oceans. Currents generated by winds are called wind currents. In temperate latitudes, westerly winds and the rotation of the earth direct surface currents to the western shores of the continents. In the northern hemisphere, they move clockwise, in the southern hemisphere - counterclockwise. In the Southern Hemisphere, wind and earth rotation have created a strong current of the Westerly Winds along the coast of Antarctica. This is the most powerful oceanic current, which encircles the entire globe from west to east in the region between 40 o and 50 o south latitude. This current serves as a barrier separating the southern waters of the Atlantic, Indian and The Pacific from the cold waters of Antarctica.

Wind and climate

Westerly winds affect the climate of a large territory of the continent of Eurasia, especially on that part of it, which is located in the temperate zone. With the breath of Vesta, coolness in the heat of summer and thaw in winter comes to the continent. It is the winds from the west in collaboration with the warm ocean current that explains the fact that the climate of northwest Europe is much warmer than the same latitudes of North America. As we move inland to the east, the influence of the Atlantic decreases, but the climate becomes completely continental only beyond the Ural ridge.

In the Southern Hemisphere, violent winds from the west are not hindered by any obstacles in the form of continents and mountains, they are free and free: they storm, fight ships, rush to the east with great speed.

Who is friends with the wind

Indomitable Vesta are especially familiar to sailors on the Cape of Good Hope routes - New Zealand - Cape Horn. Having picked up a passing sailboat, they can accelerate it faster than a diesel boat. Sailors call the westerly winds gallant in the Northern Hemisphere and the roaring forties in the Southern.

The western winds also caused a lot of trouble for the first aviators. They were allowed to fly from America to Europe, as they were passing. The pilots passed the route without any problems. The situation with the flight from Europe to America was completely different. Of course, the wind is not a hindrance to modern supersonic liners, but in the 1920s and 1930s, it turned out to be a significant obstacle.

So the French pilots Nengesière and Collie in 1919 made a historic flight across the Atlantic Ocean on the route Newfoundland - Azores - Iceland. But the same way in the opposite direction ended tragically. The pilots intended to repeat the famous route of Columbus by air, only 34 years later the wreckage of their plane was discovered on the US coast.

The tragedy is explained by the fact that strong winds the aircraft was significantly delayed, and there was simply not enough fuel to reach its destination.

Soviet pilots Gordienko and Kokkinaki were the first to defeat the oncoming Vesta in 1939, having successfully overcome the French route.