Permanent (dominant, prevailing) winds and their formation. Wind speed, strength and direction Lists constant winds known to you

Wind- traffic airrelatively 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 primarily in the horizontal direction; on other planets it is a stream of atmospheric gases characteristic of these planets. Strong winds Solar system  observed on Neptune and Saturn. The solar wind is a stream of rarefied gases from a star, and the planetary wind is a stream of gases responsible for the degassing of the planetary atmosphere into outer space. Winds, as a rule, are classified by scale, speed, types of forces that cause them, places of distribution and environmental impact.

Winds are classified, first of all, by their strength, duration and direction. Thus, short-term (several seconds) and strong air movements are considered impulses. Strong winds of medium duration (approximately 1 minute) are called squalls. The names of 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, a breeze, which depends on the difference in heating features of the relief during the day, lasts several hours, global winds caused by seasonal changes in temperature - monsoons   - have a duration of several months, while global winds caused by the difference in temperature at different latitudes and the Coriolis force blow constantly and are called trade winds. Monsoons and trade winds are the winds that make up the general and local circulation of the atmosphere.

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

Winds can also influence terrain formation, causing aeolian depositsthat form various types of soils (e.g. loess) or erosion. They can carry sand and dust from deserts over long distances. Winds spread the seeds of plants and help the movement of flying animals, which lead to the expansion of species in the new territory. Wind-related phenomena in a variety of ways affect wildlife.

Panorama of aeolian pillars in national park  Bryce Canyon (Utah)

The wind results from an uneven distribution of atmospheric pressure and is directed from the high pressure zone to the low pressure zone. Due to the continuous change in pressure over time and space, wind speed and direction are constantly changing. With altitude, 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 where the wind blows; whereas the aeronautical direction of the wind is where it blows, so 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 wind direction itself that is important, but the position of the object relative to it. So, when hunting an animal with a sharp scent, they are approached from the leeward side of it - in order to avoid the spread of smell from the hunter towards the animal.

Vertical air movement is called ascending  or downstream.

General patterns

The wind is caused by the difference in pressure between two different air areas. If there is a nonzero baric gradient (vector characterizing the degree of change in atmospheric pressure in space) , then the wind accelerates from the high pressure zone to the low pressure zone. On a planet that is spinning, this gradient is added coriolis force (one of the inertia forces acting on the ordered flow of liquid or gas in a rotating non-inertial reference frame ) . Thus, the main factors that formatmospheric circulation 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 Coriolis forces). As a result of these factors, the movement of air in mid-latitudes in the near-surface region close to the wind leads to the formation ofgeostrophic 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 parallelisobar (uh the process that occurs at constant pressure) .

An important factor that speaks of air movements is its friction against the surface, which delays this movement and makes air move towards low pressure zones. In addition, local barriers and local surface temperature gradients can create local winds. The difference between the real and the geostrophic wind is called ageostrophic wind. He 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 are usually weak in temperate latitudes and cyclones, together with anticyclones, replace each other and change their direction every few days.

Global wind effects

In most areas of the Earth, winds prevail in a certain direction. Near the poles, easterly winds usually prevail, in temperate latitudes - west winds, while east winds again dominate in the tropics. At the borders between these zones - the polar front and the subtropical ridge - there are calm zones where the prevailing winds are practically absent. In these zones, the air movement is predominantly vertical, which causes zones of high humidity (near the polar front) or deserts (near the subtropical ridge).

Passat

Atmospheric circulation

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

Scheme of global atmospheric circulation

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 sections of soil, air and water have different temperatures and, accordingly, different atmosphere pressure  (baric gradient). In addition to the Sun, the movement of air is affected by the rotation of the Earth around its axis and the heterogeneity of its surface, which causes air friction on the soil and its entrainment.

Air flows vary in scale 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, predominantly zonal transfers occur (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 circulation earthly atmosphereobserved in tropical latitudes. It is characterized by an upward movement at the equator, a flow directed to the pole at an altitude of 10-15 km, a downward movement in the subtropics and a flow towards the equator at the surface. This circulation is directly related to such phenomena as trade winds, subtropical deserts and high-altitude jet currents.

The Hadley cell, one of three atmospheric circulation cells that move heat toward the poles and determine the weather on Earth

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

Between 30 ° N and 30 ° S this energy transport is realized due to the relatively simple cyclic circulation. Air rises at the equator, is transported towards the poles at the tropopause, falls 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 towards the equator in the same horizontal plane. The tropical circulation cell is called the Hadley cell.

In the tropopause region, when the air moves towards the poles, it experiences the Coriolis force, which turns the wind to the right in the Northern Hemisphere and left in the Southern Hemisphere, creating a tropical high-altitude jet stream, which is directed from west to east. You can imagine this as a ring of air, trying to maintain 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 should rotate faster, which creates jet flows that rotate faster than the Earth itself, which are called jet currents  and directed from west to east in relation to the surface. Similarly, at the surface, the air returning to the equator rotates to the west, or slows down from the point of view of a non-rotating observer, as it moves away from the axis of rotation. These surface winds are called trade winds.

Ferrel cell (Ferrel)  - an element of the circulation of the Earth’s atmosphere in the temperate zone, located between approximately 30 and 65 degrees north latitude and 30 and 65 degrees south latitude and is limited to a subtropical ridge on the equatorial side and a polar front with a polar one. The Ferrel cell is considered a secondary 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 Ferrel 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 border, the Ferrel cell can overlap with the polar cell, and at the equatorial cell it can overlap with the Hadley cell. The prevailing near-surface winds that correspond to this cell are called westerly temperate winds.  However, local effects easily change the cell: for example, the Asian anticyclone significantly shifts it to the south, actually making it bursting.

While the Hadley cell and the polar cell are closed, the Ferrel cell is not necessarily such, as a result of which 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 high-altitude winds are truly westerly, near-surface winds often change their direction dramatically. The absence of rapid movement to the poles or to the equator does not allow these winds to accelerate, as a result, when passing through a cyclone or anticyclone, the wind can quickly change direction, and blow for days in an east 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 general movement of air near the surface is limited to approximately 30 and 65 degrees north and south latitudes, the altitude reverse air movement is much less pronounced.

Polar cell, or polar vortex  - the element of 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-altitude whirlwind swirling to the east.

This is a fairly simple circulation system, the driving force of which is the difference in the heating of the earth's surface at the poles and at moderate latitudes. Although around 60 degrees south and north latitude the air is colder and drier than in the tropics, it is still warm enough to form a convection current. Air circulation is limited by the troposphere, i.e. a layer from the surface to a height of about 8 km. Warm air rises at low latitudes and moves toward the poles at upper layers  troposphere. Reaching the poles, the air cools and falls, forming a zone of high pressure - 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, deflecting to the west under the influence of the Coriolis force, as a result of which east winds form - east winds of the polar regions surrounding the pole in the form of a vortex form at the surface.

The air stream 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 Ferrel cell, a circulation cell located at low latitudes.

The prevailing winds

Prevailing or prevailing winds  - winds that blow mainly in one direction above 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, temperate westerly winds and polar region easterly winds. In areas where global winds are weak, prevailing winds are determined by the breeze directions and other local factors. In addition, global winds may deviate from typical directions depending on the presence of obstacles.

The influence of the prevailing wind on conifers in western Turkey

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

Sand dunes in coastal and desert places can be oriented along or perpendicular to the direction of constant wind. Insects drift in the wind, and birds can fly regardless of the prevailing wind. The prevailing winds in mountainous areas can lead to a significant difference in precipitation on the windward (wet) and leeward (dry) slopes.

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

Wind Rose at Fresno Yosemite International Airport, California, 1961-1990

Wind rose is a diagram characterizing in meteorology and climatology, the wind regime in this place according to long-term observations and looks like a polygon, in which the lengths of rays diverging from the center of the diagram in different directions (horizons of the horizon) are proportional to the frequency of winds of these directions ("where" the wind blows). The wind rose is taken into account during the construction of runways of airfields, roads, the layout of populated areas (the proper orientation of buildings and streets), the assessment of the relative location of the housing and industrial zones (in terms of the direction of transport of impurities from the industrial zone) and many other economic tasks (agronomy, forestry and park management, ecology, etc.).

The wind rose, constructed from real observational data, allows us to identify the direction along the rays of the constructed polygon dominant, or prevailing  wind, from whose side the air stream most often comes to this area. Therefore, a real wind rose, built on the basis of a number of observations, can have significant differences in the lengths of different rays. What heraldry has traditionally called the “wind rose” - 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 geographical azimuths of the sides of the horizon in the form of rays.

Examples of different views

The wind rose, in addition to the direction of the wind, can show the frequency of the winds (discretized by a certain attribute - per day, per month, per year), as well as wind strength, wind duration (minutes per day, minutes per hour). Moreover, wind roses can exist both to indicate average values, and to indicate maximum values. It is also possible to create a complex wind rose, on which there will be diagrams of two or more parameters. The examples below show various options reading charts:

Eight-beam wind rose

This implies the same arrangement of cardinal points as on a compass. A point is marked on each of the rays, the distance from which to the center is (on a specified scale) the number of days per past monthwhen the wind prevailed in this direction. The points on the rays are interconnected and the resulting polygon is hatched.

16-beam wind rose

The cardinal points are indicated in letter form. Each of the 16 rays characterizing a particular direction is depicted as a segment on which the average speed for each wind direction over the past day is marked on a scale.

360-beam wind rose

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

Wind rose with numerical values \u200b\u200band extra marks

On each of the rays, the length of the segment is duplicated in the form of a numerical value that describes the number of days for a certain period when the wind of a given direction prevailed. Signs at the ends of the segments indicate the maximum wind speed. The number in the center of the chart indicates the number of days without wind. Judging by the diagram, it can be judged that the period was 90 days, of which 8 days were calm, 70 days were marked with numbers, the remaining 12 days and two directions were apparently considered insignificant and were not marked with numbers.

Tropical winds

The trade winds are 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, the northeast winds in the Northern Hemisphere and southeast winds in the South. The constant movement of the trade winds leads to mixing of the air masses of the Earth, which can manifest itself on a very large scale: for example, trade winds blowing over Atlantic oceancapable of transporting dust from African deserts to the West Indies and some areas North America.

Earth circulation processes that lead to wind formation

Monsoons are the prevailing seasonal winds that blow for several months each year in tropical areas. The term originated in British India and surrounding countries as the 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 heating of the tropical areas 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 Spanish viento de pasada - wind that favors moving, moving) - wind blowing between the tropics all year round, in the Northern Hemisphere from the north-east, in the South - from the south-east direction, separated from each other by a windless band. On the oceans, trade winds blow with the greatest accuracy; on the continents and adjacent to the latter seas, their direction is partially modified under the influence of local conditions. In the Indian Ocean, due to the configuration of the coastal mainland, the trade winds completely change their character and turn into monsoons.

Map of the winds over the Atlantic

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

Due to the action of sunlight in the equatorial strip, the lower layers of the atmosphere, heating up more strongly, rise up and tend towards the poles, while new colder air flows from the north and south come below; due to the daily 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 take a direction to the northwest (southeast trade wind). The closer a point on the globe lies to the pole, the smaller the circle it describes per day, and therefore, the lower its speed; thus, current from higher latitudes air masseshaving a lower speed than the points of the earth's surface on the equatorial strip, rotating from west to east, should lag behind them and, therefore, give a flow from east to west. At small latitudes, close to the equator, the difference in speeds for one degree is very insignificant, since the meridian arcs become almost mutually parallel, and therefore in the band between 10 ° N and 10 ° S inflowing layers of air in contact with the earth's surfaceacquire the speed of the points of the latter; as a result, near the equator, the northeastern trade wind again takes almost the northern direction, and the southeastern trade wind almost south and, mutually meeting, give a strip of calm. In the trade winds band between 30 ° N and 30 ° S in each hemisphere, two trade winds blow: in the Northern Hemisphere the north-east is lower, the south-west is above, the South-East is in the lower hemisphere and the North-West is in the upper hemisphere. The upper course is called antipassat, counter pass, or upper trade wind. Over 30 ° north and south the upper layers of the air going from the equator descend to the surface of the earth and the equatorial and polar currents cease to be correct. From the polar boundary of the trade winds (30 °), part of the air mass returns to the equator as the lower trade winds, and the other part flows to higher latitudes and is in the Northern Hemisphere as a south-west or west wind, and in the South - as a north-west or west wind .

When relatively cold air masses from temperate latitudes enter the subtropics, air is heated and powerful convective flows (air mass rise) develop at a lifting speed of 4 meters per second. Cumulus clouds form. At an altitude of 1200-2000 m, a delay layer is formed: isothermal (temperature does not change with height) or inversion (temperature increases with height). It delays the development of clouds, so there is very little rainfall. Small rains occur only occasionally.

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

Monsoon  (from Arabic. موسم ("māvsim") - time of year, by means of French mousson) - steady winds, periodically changing their direction; in summer they blow from the ocean, in winter - from land; characteristic of tropical regions and some coastal temperate countries ( Far East) Monsoon climate is characterized by high humidity in the summer.

In each place 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 other. In another season, the prevailing wind direction will be opposite or close to the opposite. Thus, in each monsoon region there are summer and winter monsoons with mutually opposite or, at least, with sharply different prevailing directions.

Of course, in addition to the prevailing winds, winds of other directions are observed in each season: the monsoon is experiencing interruptions. In the transitional seasons, in spring and autumn, when the monsoon changes, the stability of the wind regime is violated.

The stability of the monsoons is associated with a stable distribution of atmospheric pressure during each season, and their seasonal change is associated 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 direction of the wind also changes.

In the case of monsoons, as in the case of trade winds, the stability of distribution does not mean at all that during the season the same anticyclone or the same depression is kept over this area. For example, in the winter over East Asia a number of anticyclones are successively replaced. But each of these anticyclones remains relatively long, and the number of days with anticyclones significantly exceeds the number of days with cyclones. As a result, the anticyclone is obtained on a long-term average climate map. The northern wind directions associated with the eastern periphery of 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 predominance of some over others. In the same areas of the Earth where cyclones and anticyclones quickly replace each other and little prevail one over the other, the wind regime is variable and does not look like a 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; peculiar to tropical regions and some coastal countries of the temperate zone (for example, the Far East). The monsoons possess the greatest stability and wind speed in some regions of the tropics (especially in equatorial africa, the countries of South and Southeast Asia and the Southern Hemisphere up to the northern parts of Madagascar and Australia). In a weaker form and in limited territories, monsoons are also found in subtropical latitudes (in particular, in the south of the Mediterranean Sea and in North Africa, in the Gulf of Mexico, in eastern Asia, in South America, in southern Africa and Australia).

Over hr. Windhya (India)

Calcutta (India)

Arizona (USA)

Darwin (Australia)

Temperate westerly winds - 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 surface part of the Ferrel 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 gradient of wind speed 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 westerly winds  temperate zone.

Map of the trade winds and the temperate westerly winds

The temperate westerly winds blow harder in the winter, when the pressure above the poles is lower, and weakly in the summer. These winds are strongest in the Southern Hemisphere, where there is less land, which tends to deflect or delay the wind. The band of strong temperate westerly winds 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 transporting warm equatorial waters to the western shores of the continents, especially in the southern hemisphere.

Gulf Stream Map by Benjamin Franklin

Eastern winds of the polar regions, the surface part of the polar cells is mainly dry winds blowing from the polar regions of high pressure to the regions of low pressure along the polar front.

These winds are usually weaker and less regular than the westerly winds of temperate latitudes. Due to the small quantity solar heat, the air in the polar regions cools and falls down, forming high pressure areas and pushing the circumpolar air towards lower latitudes. This air, as a result of the Coriolis force, deviates to the west, forming northeast winds in the Northern Hemisphere and southeast winds in the South.

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

The most important local winds on Earth

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

Local winds include breeze,  changing 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 reservoirs (breezes) or mountains, their spread relative to the general circulation flows and the location of mountain valleys (phen, boron, mountain-valley), as well as with a change in the general atmospheric circulation by local conditions (summ , 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 attributed to local winds and give them their own names.

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

Afghan

Afghan   - a dry, baking local wind, with dust that blows in Central Asia. It has a southwestern character and blows in the upper Amu Darya. Blowing from a few days to several weeks. In early spring with showers. Very aggressive. In Afghanistan called kara-buranwhich means black storm  or body shuravi - soviet wind.

Biza

Bise   - cold and dry north or northeast wind  in the mountains of France and Switzerland. Bizet is similar to boron.

Bora

Bora (ital. bora, from Greek. βορέας - north wind; “Northwind” - cold north wind) - a strong cold gusty local wind that occurs when a stream of cold air meets an elevation in its path; overcoming the obstacle, bora collapses with great force on the coast. The vertical dimensions of the burs are several hundred meters. Affects, as a rule, small areas where low mountains directly border the sea.

The pattern of occurrence of boron

In Russia, the pine forests of the Novorossiysk Bay and the 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 Olkhonsky Strait), the Chukchi city of Pevek (the so-called “Yuzhak”) are especially strong. )

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

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

Novorossiysk, 1997

In Europe, the most famous are the forests of the Adriatic Sea (in the cities of Trieste, Rijeka, Zadar, Senj, etc.). In Croatia, the wind is called bora. The Nord wind in the Baku region is similar to that of the wind, the mistral on the Mediterranean coast of France from Montpellier to Toulon, the North North in the Gulf of Mexico. The duration of the burs is from one day to a week. The daily temperature difference during bora can reach 40 ° C.

Bora

Bora occurs in Novorossiysk and the Adriatic coast when a 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 rushes down the ridge, while acquiring a high speed.

Before the appearance of the bora at the tops of the mountains, you can observe the thick clouds that the inhabitants of Novorossiysk call "beard". Initially, the wind is extremely unstable, changes direction and strength, but gradually acquires a certain direction and great speed - up to 60 m / s on the Markotkh pass near Novorossiysk. In 1928, a gust of wind of 80 m / s was recorded. On average, the wind speed at boron reaches in the Novorossiysk region in winter more than 20 m / s. Falling to the surface of the water, this downdraft causes a gale, causing severe unrest at sea. At the same time, the air temperature drops sharply, which was quite high above the warm sea before the start of the bora.

Sometimes boron causes significant damage in the coastal strip (for example, in Novorossiysk in 2002, boron caused the death of several tens of people); at sea, the wind contributes to strong waves; intensified 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 the ice crust forms is Senj). Sometimes bora is felt and far from the coast (on the Black Sea, 10-15 kilometers inland, on the Adriatic at some synoptic positions covers a significant part of the sea).

Varieties of burs are tramontana, sarma.

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

Clouds of Tramontana, Southern France

The form of the name varies slightly in each country. AT english  passed from Italian (tramontana), which, in turn, is the amended Latin word trānsmontānus (trāns- + montānus). In Catalonia and Croatia, the wind is called the Tramuntana. In Spain, on the island of Mallorca, there is a mountainous region of Serra de Tramuntana. 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 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: a day (or sea) breeze blows from the sea to the coast warmed by the daytime rays of the Sun. The night (or coastal) breeze has the opposite direction.

A: Sea breeze (daytime), B: Coastal breeze (nighttime)

The speed of the breeze is small, and is 1-5 m / s, rarely more. The breeze is noticeable only in conditions of weak general air transport, as a rule in the tropics, and in the middle latitudes - in stable, calm weather. The vertical height (power) of the air layer — up to 1-2 km during the day, slightly less at night. At a higher altitude, the reverse flow is observed - anti-breeze.  Breeze circulation affects areas of the coast and the sea with a width of 10-50 km. The sea breeze lowers the air temperature during the day and makes the air more humid. A breeze more often occurs in summer when the temperature difference between land and water reaches highest values.

Garmsil

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

Foehn   (German Föhn, from lat. favonius  - Roman equivalent of Zephyr) - a strong, gusty, warm and dry local wind blowing from the mountains into the valleys.

Cold air from highlands quickly descends along relatively narrow intermountain valleys, which leads to its adiabatic heating. When lowering for every 100 m, 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 hairdryer lasts less than a day, but sometimes it lasts up to 5 days, and changes in temperature and relative humidity can be quick and sharp.

Hair dryers are especially frequent in spring, when the intensity of the general circulation of air masses rises sharply. Unlike hair dryers, boron is formed during the invasion of dense masses of cold air.

The name of this wind has become a household name for a household appliance for drying hair - a hair dryer. The word came into our speech in a slightly distorted form due to inaccurate transliteration of the German brand Fön, under which these electrical appliances have been produced since 1908.

(To be continued)

Wind is a horizontal and evenly moving air stream relative to the surface of the earth. There are a huge number of local winds, which can not be explained by the example of ordinary observations because of the inherent specific features characteristic of a particular region. So, to talk about what kind of winds are on the coast, one can, for example, observe such things: at noon a breeze blows from the sea - cool, gentle, and at night the same wind moves from land towards the sea. In deserts and mountainous regions, “mountain” or valley winds “live” mainly. However, there are types of winds that apply to the entire planet as a whole.

What are the winds

1. Monsoon is a wind with a periodic character, and carrying a lot of moisture. In winter, the monsoon blows from land to the ocean, and in summer from the ocean to land. Monsoons predominantly prevail in the tropical zone and are essentially seasonal winds lasting several months each year.
2. The trade winds are winds with a constant character, moving with a fairly stable force of three to four points. The trade winds move in almost the same direction, sometimes deviating slightly. Such dynamics of movement leads to a mixing of the air masses of the planet, up to global scales: for example, trade winds blowing over the Atlantic Ocean can carry dust particles from African deserts to the West Indies and several North American regions.
3. Local winds:
   • Breeze - a warm breeze blowing from the coast to the sea at night (coastal breeze) and in the opposite direction during the day (sea breeze). The main generators of predominant winds in coastal areas are sea and continental breezes. Due to the fact that the sea (body of water) warms up more slowly than land due to the greater heat capacity of water, the air heated more strongly above the land rises, forming a zone of low pressure. This creates a difference in atmospheric pressure between the air currents and creates a cool sea breeze on the coast.

     At night, in view of the lower heat capacity, the land cools faster and the sea breeze stops. At the moment when the land temperature is lower than the temperature on the surface of the reservoir, a reverse pressure drop is formed, creating (if there is no strong wind from the sea) a continental breeze moving from land to the sea.

   • Bora - a wind with a cold, sharp character, moving from the mountains to the coast or valley.
   • Föhn is a dry, strong and warm wind that moves from the mountains to the valley or coast.
   • Cirocco - the name in Italian is southwestern or strong south windformed in the Sahara desert.
4. Variable and constant winds.

   The nature of the movement of air masses also helps to understand what winds are. So, variable winds are able to change their direction. These include the breezes already discussed above (translated from French as “Breeze” means a light breeze), since they change their direction of movement twice a day (day and night).

   Monsoons are born just like breezes. They change the direction of their movement twice a year seasonally (in summer and winter). The Arabic name for the wind is "monsoon" in translation and means "season". When the summer monsoon forms, thunderstorms occur due to the strong saturation of air with sea water, and in winter dry and cold air moves from land.

5. Also, winds can be described as gusty and light, or give them a name taking into account the direction of their movement, for example: east, southwest, etc.

Wind  - the movement of air is usually in the horizontal direction relative to the earth's surface. Air moves out. The cause of the wind is the uneven heating of various parts of the Earth. Over the vast territories of our planet, systems of constant and variable winds - air currents - are forming.

Permanent winds (air currents):

Trade winds. They blow from the tropics of the Northern and Southern Hemispheres, where high-pressure regions, located in the low-pressure region, are formed. As a result of the Earth's rotation around its axis, these winds deviate: in the Northern Hemisphere they blow from the northeast to the southwest, in the Southern Hemisphere from the southeast to the northwest. The eastern coast, Africa, is year-round under the influence of trade winds, which arise over the oceans and bring throughout the year. The North is influenced by the trade winds, which originate at 30 ° latitudes of the Northern Hemisphere in central Asia. These winds do not bring precipitation: they come dry and hot. The influence of these winds can explain the location in the big world - .

Westerly winds. These are the winds prevailing in the troposphere and stratosphere of the middle latitudes of the Earth. They blow from the tropics of the Northern and Southern Hemisphere, where a high-pressure region forms, towards 60 ° latitudes, where low-pressure regions form. Due to the rotation of the Earth, they constantly deviate to the east (to the right in the Northern Hemisphere, to the left in the Southern Hemisphere) and create air flow from west to east.

There are also local winds:

Breeze  (French brise - light breeze). This is a local wind of low speed, changing its direction twice a day. It occurs on the shores of the seas, lakes. In the afternoon, the land warms up faster than water. An area of \u200b\u200blow pressure is established above the land, and high above the water, and the daytime breeze blows from the sea or lake on the coast. At night, the picture changes. The land cools faster than water, and the night breeze blows from the cooled coast, over which the high pressure region is established, to the heated one.

In the era of sailing, breezes were used to start sailing.

Bora  (Italian. bora; Greek. boreas - north wind). This is a strong, gusty wind blowing from coastal mountains towards the sea, mainly in the cold season. Boron occurs when cold air above land is separated from warm air above water by a low ridge. Cold air gradually accumulates in front of the ridge and then slides down to the sea with great speed, so the temperature on the coast drops sharply. Bora is especially typical for the coast. The set leads to icing of coastal buildings, to capsizing of ships.

A variety of bora is the Sarma wind, the name of which comes from the name of the river flowing into. This, flying suddenly and raising steep on the lake. It occurs during transshipment through the mountain ranges. As this wind approaches, meteorologists broadcast a storm warning.

Fyon.It is a warm and dry gusty wind from the mountains. It often blows in winter and spring and causes rapid snowmelt. Fen is very common in the mountains of Central Asia,.

Simoom  (Arabic) - a sultry wind in the deserts and North Africa, carrying hot sand and dust. This wind occurs during strong warming of the Earth in

SECTION 3 GEOGRAPHICAL SHELL

Theme 2. Atmosphere

§ 36. Wind. Constant and variable winds

Remember

How do you watch the wind?

Which winds prevail in your area?

Wind is the movement of air in a horizontal or close direction. In this case, air moves from a zone of high atmospheric pressure to an area with low atmospheric pressure. Wind is characterized by speed, strength and direction. Wind speed is measured in meters per second (m / s) or in kilometers per hour (km / h). To convert meters per second to kilometers per hour, you need to multiply the speed in meters per second by 3.6.

The strength of the wind is determined by the pressure of moving air on objects. It is measured in kilograms per square meter (kg / m2). The strength of the wind depends on its speed. So, the wind at a speed of 100 km / h has a force 10 times greater than at a speed of 10 km / h. The greater the difference in atmospheric pressure, the stronger and faster the wind blows. The absence of any signs of wind is called calm.

Modern Facts

The strongest winds. Outlying parts of Antarctica, where the winds blow for 340 days a year, are considered the “Pole of Winds" on Earth. The highest wind speed - 371 km / h - was recorded in 1934 in the United States, on a mountain in the state of New Hampshire. In Ukraine, the strongest wind was in the city of Ai-Petri in the Crimea (its speed reached 180 km / h).

The direction of the wind is determined by the position of that side of the horizon from where it blows. To indicate the direction of the wind in practice, the horizon is divided into eight directions. Of these, four head ones are north (Mon), south (S), east (Cx) and west (W), and four intermediate ones are northeast (Sev-East), northwest (Sev-Zap), and southeast ( Front-Cx) and southwestern (Front-Zx).

For example, when the wind blows from a location located between the south and east, it is called southeastern (PD-Cx). The direction and speed of the wind is determined using a weather vane (Fig. 97). A clear idea of \u200b\u200bthe directions of the winds that prevail in a given area is given by a special diagram - a rose of winds (Fig. 98). This is a graphic representation of the repeatability of wind directions. The length of its rays is proportional to the frequency of winds in a given direction.

Fig. 97. Weather vane

PRACTICAL WORK No. 8(continued)

Weather Observations: composing a wind rose

Using the data in the table, build a wind rose. To do this, first draw the coordinates, indicating four wind directions and four intermediate. At the scale of your choice, set aside the number of lines corresponding to each direction. The ends of the segments are connected in series. Paint the resulting wind rose and indicate which direction the wind prevailed. In Figure 98, note how the winds of various directions denote.

Fig. 98. Wind rose

Direction of the wind
Wind repeatability,%

Constant and variable winds. There is not a single windless place on the globe. There are many different types of winds. There are winds that blow constantly, and there are those that change their direction during the day or year. Permanent winds - trade winds - arise between the high tropical and equatorial low zones of atmospheric pressure in the Northern and Southern hemispheres of the Earth (Fig. 99). Due to the rotation of the globe, trade winds in the Northern Hemisphere are moving from the northeast to the southwest, and in the South from the southeast to the northwest. The trade winds hardly change their direction during the year. their speed is on average 5-6 m / s, and the vertical thickness reaches 2-4 km and increases towards the equator.

In temperate latitudes, westerly winds blow. They are also permanent.

Fig. 99. The trade winds

Fig. 100. Education day (a) and night (b) breeze

There are much more variable winds on the globe than constant ones. Distributed only in certain territories, they are called local.

Local winds blow over a relatively small area (from hundreds of meters to tens of kilometers) and significantly affect the weather in this area. An example of a local breeze wind. Translated from French, this word means "a breeze." Its speed is really negligible - up to 4 m / s. The breeze blows with daily intervals on the coast of the seas, large lakes and some large rivers. This wind changes direction twice a day, which is caused by uneven heating of the land surface and the reservoir. The daytime, or sea, breeze moves from the water surface to the land, and the night, or coastal, moves from the chilled coast of the land to the reservoir (Fig. 100).

The breeze occurs mainly in the summer, when the temperature difference between land and water reaches its highest value. In Ukraine, breezes are observed on the coast of reservoirs, the Black and Azov Seas.

Amazing phenomena

Wind from the mountain peaks.

Interesting local winds are fiones, which do not have a certain periodicity. They are not constant and last on average from one to two days.

Fion is a strong, gusty, dry and warm wind blowing from mountain peaks into valleys. It arises when air passes over the crest of a mountain range and, descending the slope, quickly heats up (Fig. 101). In this case, the temperature can reach maximum values \u200b\u200bfor a given time of the year. So, with a strong fion on the icy island of Greenland, the temperature rises by 20-25 ° C. The fion causes snowmelt in the mountains in winter, and droughts and fires in summer. In the mountainous regions of Ukraine, fiones, which blow from the southeastern slopes of the Crimean mountains near Alushta, can suddenly raise the temperature here to 28 ° С. Fioni in the Ukrainian Carpathians have a speed of up to 25 m / s.

Fig. 101. Education fionov

Fig. 102. The movement of monsoons

Monsoons are also attributed to winds that change their direction. The word "monsoon" is translated from Arabic as "season". This name is not accidental, because the monsoon changes its direction twice a year: in winter it blows from land to ocean, and in summer, on the contrary, from ocean to land (Fig. 102). (Think about why the monsoon changes direction in the seasons.) Monsoon winds are best expressed in the south and east of Asia, in the north of the Indian and in the west of the Pacific Ocean. Especially powerful is the Asian summer monsoon. It contains a large number of  moisture and heat, associated with heavy rainfall.

Wind is the horizontal movement of air, resulting from the difference in atmospheric pressure.

Wind is characterized by speed, strength and direction.

Constant winds blow constantly, variable winds change their direction during the day or year.

Questions and tasks for self-testing

Build a wind rose from your observations. Explain which winds prevail in your area. Schematically draw the direction of the wind according to the following data: a) the pressure in point A is 760 mm Hg. Art., and in paragraph B - 784 mm RT. st .; b) on the coast, the pressure is 758 mm Hg. Art., and above the lake - 752 mm RT. Art. In which case will the wind be stronger?

Choose from the listed winds one that almost does not change its direction: a) trade wind; b) monsoon c) breeze.

What is the cause of the wind? What determines the strength and speed of the wind?

Name the constant winds above the earth's surface and explain their formation. and got the best answer

Reply from исaisiya Konovalova [guru]
trade winds, monsoons, breezes.

Answer from 2 answers[guru]

Hello! Here is a selection of topics with answers to your question: Name the constant winds above the earth's surface and explain their formation.

Answer from Ѓrazaeva Tamila[newbie]
At some latitudes of the Earth there are high and low pressure belts. For example, atmospheric pressure is lower above the equator, because the surface of the earth is very hot there. Strong global winds, called Westerly winds and trade winds, are blowing from the high pressure belts towards the low pressure belts. However, they do not move directly from south to north and from north to south. This is due to the fact that the rotation of the Earth forces global winds to turn to the side.

Answer from DEMENKOVA AVATARIA[newbie]
about

Answer from Kazimagomed Hajibeyov[master]
google to help .. but in general this is an easy question ... topic is 6th grade.

Answer from skyrim skairim[newbie]
trade winds, monsoons, breezes.
The trade winds are formed due to the pressure drop in the tropical regions of both hemispheres and at the equator. These winds are deflected by the rotation of the Earth: the trade winds of the northern hemisphere blow from the northeast to the southwest, and the trade winds of the south - from the southeast to northwest. They are quite stable in temperature and humidity and are one of the most important factors in climate formation.
Monsoons are formed due to pressure drops resulting from temperature differences. A distinctive feature of monsoons is that in the warm and cold season they are directed in opposite directions: from sea to land and from land to sea. In winter, air is warmer above the sea than above land, atmospheric pressure above the sea is lower, therefore, monsoons are directed from land to sea. In the warm season, the opposite is true: the air is warmer over land, a low pressure region forms there. Monsoons at this time blow to land and bring with them heavy rainfall.
AT tropical zone  monsoons are especially active, but they exist outside the tropics. Areas dominated by monsoons are characterized by very humid summers. A great example of the influence of monsoons is India, where the Himalayan mountains are stopped by a humid wind, so in northern India, Burma, Nepal there is a huge amount of rainfall.
Breezes, like monsoons, change their direction to the opposite, but this happens with a frequency of one day. These are not very large-scale winds, they are formed near the seas, oceans, large lakes, rivers. In the afternoon, air over land heats up, warm air  rises, and in its place comes cooler, with water. At night, on the contrary, it is warmer above the water; colder air masses come here from land. Thus, a breeze blows from water to land during the day, and from land to water at night.