Wind formation

Although the air is invisible to the eye, we always feel its movement - the wind. The main cause of wind is the difference in atmospheric pressure over areas of the earth's surface. As soon as the pressure decreases or increases somewhere, the air will be directed from the place of greater pressure towards less. And the pressure balance is disrupted by the unequal heating of different parts of the earth's surface, from which the air is heated differently.

Let's try to imagine how this happens using the example of wind that arises on the coasts of the seas and is called breeze. Parts of the earth's surface - land and water - heat up unequally. Sukhodol heats up faster. Therefore, the air above it will heat up faster. It will rise up, the pressure will decrease. At this time, the air above the sea is colder and, accordingly, the pressure is higher. Therefore, air from the sea moves to land to replace the warm air. So the wind blew - afternoon breeze. At night, the opposite happens: land cools faster than water. The cold air above it creates more pressure. And above water, it retains heat for a long time and cools slowly, the pressure will be lower. Cold air from land from an area of ​​high pressure moves towards the sea, where the pressure is lower. Arises night breeze.

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

Determining wind direction and speed

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

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

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

Types of winds

Monsoon is a periodic wind that carries a large number of moisture blowing from land to ocean in winter, and from ocean to land in summer. Monsoons are observed mainly in the tropical zone. Monsoons are seasonal winds that last for several months each year in tropical areas. The term originated in British India and surrounding countries as a name for the seasonal winds that blow from the Indian Ocean and Arabian Sea to the northeast, bringing significant amounts of 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 areas in summer months, that is, Asia, Africa and North America from May to July and Australia in December.

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

Local winds:

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

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

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

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

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

Variable and constant winds

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

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

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

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

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



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

Answer from ЂaisiaKonovalov[guru]
trade winds, monsoons, breezes.

Answer from 2 answers[guru]

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

Answer from Razaeva Tamila[newbie]
At some latitudes of the Earth there are belts of high and low pressure. For example, above the equator the atmospheric pressure is lower because the surface of the earth there is very hot. Strong global winds, called westerlies and trade winds, blow from high pressure belts towards low pressure belts. They, however, do not move directly from south to north and from north to south. This occurs because the rotation of the Earth forces global winds to turn sideways.

Answer from DEMENKOVA AVATARIA[newbie]
O

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

Answer from Skyrim skyrim[newbie]
trade winds, monsoons, breezes.
Trade winds are formed due to pressure differences 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 northeast to southwest, and the trade winds of the southern hemisphere blow from 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 differences resulting from temperature differences. A distinctive property of monsoons is that during the warm and cold seasons they are directed in opposite directions: from sea to land and from land to sea. In winter, the air over the sea is warmer than over the land, the atmospheric pressure over the sea is lower, therefore, the monsoons are directed from the land to the sea. In the warm season, it’s the other way around: the air is warmer over land, and an area of ​​low pressure forms there. At this time, monsoons blow onto land and bring with them heavy rainfall.
In the tropical zone, monsoons are especially active, but they also exist outside the tropics. Monsoon-dominated areas are characterized by very humid summers. An excellent example of the impact of monsoons is India, where the Himalayan mountains stop the humid wind, so northern India, Burma, and Nepal receive huge amounts of rainfall.
Breezes, like monsoons, change their direction to the opposite, but this happens every day. These are not very large-scale winds; they form near seas, oceans, large lakes, and rivers. During the day, the air over land heats up, warm air rises, and is replaced by cooler air from the water. At night, on the contrary, it is warmer over the water; colder air masses come here from the land. Thus, during the day the breeze blows from water to land, and at night - from land to water.

Predominant winds- winds that blow predominantly in one direction over a specific point on the earth's surface. They are part of the global pattern of air circulation in the Earth's atmosphere, including trade winds, monsoons, temperate westerlies, and polar easterlies. In areas where global winds are weak, prevailing winds are determined by breeze directions and other local factors. In addition, global winds may deviate from typical directions depending on the presence of obstacles.

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

Rose of Wind - graphic image wind frequencies of each direction in a given area, plotted as a histogram in polar coordinates. Each line in the circle shows the frequency of the winds in a particular direction, and each concentric circle corresponds to a specific frequency. The wind rose can also contain additional information, for example, each line can be colored in different colors, corresponding to a certain range of wind speed. Compass roses often have 8 or 16 lines corresponding to the cardinal directions, that is, north (N), northwest (NW), west (W), etc., or N, NNW, NW, NWW, W, etc. etc., sometimes the number of lines is 32. If the frequency of wind in a certain direction or range of directions is significantly higher than the frequency of wind in other directions, the presence of preferential winds in that area is said to exist.

Climatology

Trade winds and their influence

Temperate westerly winds and their influence

Western winds temperate zone blow in mid-latitudes between 35 and 65 degrees north or south latitude, in a west to east direction north of a high pressure area, driving extratropical cyclones in the corresponding 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 transporting warm equatorial waters and air masses to the western coasts of continents, especially in the southern hemisphere due to the predominance of oceanic space.

Eastern winds of the polar regions

Main article: Easterly winds of the polar regions

Polar easterlies are dry, cold winds blowing from polar areas of high pressure to lower latitudes. Unlike trade winds and western 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 areas of high pressure, pushing the air towards the equator; this flow is deflected to the west by the Coriolis effect.

Influence of local features

Sea breeze

In areas where there are no strong air currents, breeze is an important factor in the formation of prevailing winds. During the day, the sea warms up to a greater depth than land, since water has a greater specific heat capacity, but at the same time much slower than the surface of the earth. The temperature of the earth's surface rises, and the air above it warms up. Warm air is less dense and therefore rises. This rise reduces the air pressure above the ground by about 0.2% (at sea level). Cold air over the sea, which has higher pressure, flows towards land at lower pressure, 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 the sea temperature, a night breeze occurs - blowing from the land to the sea.

Winds in mountainous areas

In areas with uneven terrain, the natural wind direction may change significantly. In mountainous areas, air flow distortions are more serious. Strong upward and downward currents and vortices arise over the hills and valleys. If there is a narrow passage in a mountain range, the wind will rush through it with increased speed, according to Bernoulli's principle. At some distance from the downdraft, the air may 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 during the day, air currents similar to sea breezes can appear. At night the hillsides cool down. The air above them becomes colder, heavier and falls into the valley under the influence of gravity. This wind is called a mountain breeze or katabatic wind. If the slopes are covered with snow and ice, katabatic winds will blow downhill throughout the day. Hillsides not covered with snow will warm up throughout the day. Then rising air currents form from the colder valley.

Impact on precipitation

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

Impact on nature

Predominant winds also influence wildlife for example, they carry insects, while birds are able to fight the wind and stay their course. As a result, prevailing winds determine the migration directions of insects. Another effect of wind on nature is erosion. To protect against such erosion, wind barriers are often constructed in the form of embankments, shelterbelts, and other barriers oriented, to increase efficiency, perpendicular to the direction of prevailing winds. Prevailing winds also result in 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 on the American Meteorological Society Wayback Machine. 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 (undefined) (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 (undefined) (unavailable link). American Meteorological Society (2009). Retrieved April 15, 2009. Archived August 22, 2011.
9. Sue Ferguson. Climatology of the Interior Columbia River Basin (undefined) (unavailable link). Interior Columbia Basin Ecosystem Management Project (September 7, 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 (undefined) . The National Oceanographic Partnership Program (2003). Retrieved September 10, 2008. Archived from the original on August 22, 2011.
12. Erik A. Rasmussen, John Turner. Polar Lows. - Cambridge University Press, 2003. - P. 68.
13. Glossary of Meteorology (2009).

Wind is one of the most unique natural phenomena. We cannot see or touch it, but we are able to observe the results of its manifestation, for example, how it slowly or quickly drives clouds across the sky, bends trees to the ground with its force, or slightly ruffles leaves.

Wind concept

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

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

Types of winds

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

• local;
• permanent;
• regional.

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

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

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

Constant winds include those that depend on the overall air circulation. They are stable, uniform, constant and strong. These include:

• trade winds - winds from the east, characterized by constancy, unchanging direction and strength of 3-4 points;
• anti-trade winds are winds from the west that carry huge air masses.

Regional wind appears as a result of pressure differences, a little similar to local wind, but more stable and powerful. A striking representative of this species is the monsoon, which originates in the tropics, at the border with the ocean. It blows periodically, but in large streams, changing its direction a couple of times a year: during the summer season - from water to land, during winter - vice versa. The monsoon brings a lot of moisture in the form of rain.

Strong wind is...

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

Types of strong winds

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

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

Description of wind force

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

Definition of the solar wind

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

There are slow (400 km/s), fast (700 km/s), and high-speed (up to 1200 km/s) solar winds. They form a region of space around the central celestial body that protects the Solar System from interstellar gas entering it. In addition, thanks to them, phenomena such as the radiation belt and the aurora occur on our planet. That's what the solar wind is.

Wind- movement air relative 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 wind speed and direction, used at airfields

On Earth, wind is a flow of air that moves primarily in a horizontal direction; on other planets it is a flow of atmospheric gases characteristic of these planets. Strongest winds solar system observed on Neptune and Saturn. The solar wind is a flow of rarefied gases from a star, and the planetary wind is a flow of gases responsible for the degassing of the planetary atmosphere in space. Winds are generally classified by their size, speed, the types of forces that cause them, where they travel, and their 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 movements of air. Strong winds of average duration (about 1 minute) are called squalls. The names of longer lasting winds depend on the strength, for example, such names are breeze, storm, gale, hurricane, typhoon. The duration of the wind also varies greatly: some thunderstorms can last several minutes, breezes that depend on differences in the heating of terrain features throughout the day last several hours, global winds caused by seasonal temperature changes - monsoons - have a duration of several months, while 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 the winds that make up the general and local circulation of the atmosphere.

Winds have always influenced human civilization, inspiring mythological stories, influencing historical actions, expanding the range of trade, cultural development and warfare, and supplying energy for a variety of energy production and recreation mechanisms. Thanks to sailing ships that sailed using the wind, it became possible for the first time to travel long distances across seas and oceans. Balloons, which also moved with the help of wind, made air travel possible for the first time, 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, on large bodies of water often lead to the destruction of single-piece buildings, and in some cases, winds can increase the scale of the fire.

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

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

Wind arises as a result of uneven distribution of atmospheric pressure and is directed from a high pressure zone to a low pressure zone. 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 the decrease in friction force.

For visual assessment of wind speed it is used 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 the wind is blowing, so the values ​​differ 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 keen sense of smell, they approach it from the leeward side - in order to avoid the spread of smell from the hunter towards the animal.

The vertical movement of air is called ascending or downward flow.

General patterns

Wind is caused by the difference in pressure between two different air areas. If there is a non-zero pressure gradient (vector characterizing the degree of change in atmospheric pressure in space) , then the wind moves with acceleration from an area of ​​high pressure to an area of ​​low pressure. On a planet that rotates, this gradient is added Coriolis force (one of the inertial forces acting on an ordered flow of liquid or gas in a rotating non-inertial frame of reference ) . Thus, the main factors that formatmospheric circulation on a global scale is the difference in air heating andsolar wind betweenequatorial and polarareas that cause a difference in temperature and correspondingly,density of air flows, and in turn the difference in pressure (as well as Coriolis forces). As a result of the action of these factors, the movement of air in mid-latitudes in the near-surface region close to the wind leads to the formationgeostrophic wind (this is a theoretical wind that is the result of a complete balance between the Coriolis force and the pressure gradient) and its movement, directed almost parallelisobars (uh is a process that occurs at constant pressure) .

An important factor that indicates the movement of air is its friction against the surface, which retards this movement and causes the air to move towards areas of low pressure. In addition, local barriers and local surface temperature gradients are capable of creating 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 are usually weak in temperate latitudes and cyclones, together with anticyclones, replace each other and change their direction every few days.

Global effects of wind generation

Most regions of the Earth are dominated by winds that blow in a particular direction. East winds usually dominate near the poles, westerlies dominate in temperate latitudes, while east winds again dominate in the tropics. On the borders between these belts - the polar front and the subtropical ridge - there are zones of calm, where the prevailing winds are practically absent. In these zones, air movement is predominantly vertical, resulting in areas 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 a hemispheric or entire scale 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, influencing the weather anywhere on the planet.

Global atmospheric circulation diagram

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 friction of the air on the soil and its entrainment.

Air currents vary in scale from tens and hundreds of meters (such movements are created by 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 zonality). 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 near the equator, a poleward flow at a height of 10-15 km, a downward movement in the subtropics, and an equatorward flow near the surface. This circulation is directly related to phenomena such as trade winds, subtropical deserts and high-altitude jet streams.

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

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 accomplished differs between tropical and extratropical latitudes.

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

At the tropopause, as air moves toward the poles, it experiences the Coriolis force, which turns the wind to the right in the Northern Hemisphere and to the left in Southern Hemisphere, creating a tropical high-altitude jet stream that flows from west to east. You can think of this as a ring of air trying to maintain its angular momentum in an absolute coordinate system (not rotating with the Earth). When the ring of air moves poleward, it is closer to the axis of rotation and must rotate faster, which creates jet streams that rotate faster than the Earth itself, which are called jet streams and directed from west to east relative to the surface. Similarly, at the surface, air returning to the equator rotates westward, or slows down from the perspective of a non-rotating observer as it moves away from the axis of rotation. These surface winds are called trade winds.

Ferrel cell (Ferrell)- element of the circulation of the earth's atmosphere in the temperate zone, located approximately between 30 and 65 degrees northern latitudes s and 30 and 65 degrees south latitude and is limited by the subtropical ridge on the equatorial side and the polar front on the polar side. 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 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 subpolar boundary, the Ferrell cell can overlap with the polar cell, and at the equatorial boundary with the Hadley cell. The prevailing 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 polar cell are closed, the Ferrell cell is not necessarily so, with the result that temperate westerlies are not as regular as trade winds or polar easterlies and are dependent on local conditions. Although the high-altitude winds are truly westerly, the surface winds often and abruptly change their direction. The lack of rapid movement towards the poles or towards 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 blow in the east or another direction for days.

The location of a cell strongly depends on the location of the corresponding high-altitude jet stream, which determines the location of the band of near-surface cyclones. Although general air movement at the surface is limited to approximately 30 and 65 degrees north and south latitudes, high-altitude backflow 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 that spins to the west, emerging from the poles; and a high-altitude vortex spinning to the east.

It's pretty simple circulation system, the driving force of which is the difference in heating of the earth's surface at the poles and at temperate latitudes. Although the air is colder and drier in the polar front region around 60 degrees south and north than in the tropics, it is still warm enough to form a convection current. Air circulation is limited by the troposphere, that is, a layer from the surface to a height of about 8 km. Warm air rises at low latitudes and moves poleward in the upper troposphere. Reaching the poles, the air cools and descends, forming a zone of high pressure - a polar anticyclone.

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 influence of the Coriolis force, as a result of which easterly winds are formed near the surface - easterly winds of the polar regions, surrounding the pole in the form of a vortex.

The flow of air 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 found at low latitudes.

Prevailing winds

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

Effect of prevailing wind on a coniferous tree in western Turkey

To determine the direction of the prevailing wind, it 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 locations may be oriented along or perpendicular to the direction of the constant wind. Insects drift with the wind, and birds can fly regardless of the prevailing wind. The prevailing winds in mountainous areas can lead to significant differences in precipitation on windward (wet) and leeward (dry) slopes.

Rose of Wind- a graphical representation of the frequency of winds in each direction in a given area, constructed in the form of a histogram in polar coordinates. Each line in the circle shows the frequency of the winds in a particular direction, and each concentric circle corresponds to a specific frequency. The wind rose can also contain additional information, for example, each line can be colored in different colors, corresponding to a certain range of wind speed. Compass roses often have 8 or 16 lines corresponding to the cardinal directions, that is, north (N), northwest (NW), west (W), etc., or N, NNW, NW, NWW, W, etc. etc., sometimes the number of lines 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, they speak of the presence of preferential winds in this area.

Wind rose of Fresno-Yosemite International Airport, California, 1961-1990

A wind rose is a diagram that characterizes in meteorology and climatology the wind regime in a given place based on 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 winds in these directions (“from” The wind's blowing). The wind rose is taken into account when constructing airfield runways, highways, planning of populated areas (expedient orientation of buildings and streets), assessment relative position residential areas and industrial zones (from the point of view of the direction of transfer of impurities from the industrial zone) and many other economic tasks (agronomy, forestry and park management, ecology, etc.).

The wind rose, constructed based on real observational data, allows one to determine the direction of the constructed polygon based on the length of the rays dominant, or predominant wind, from which the air flow most often comes to a given area. Therefore, a real wind rose, built on the basis of a series of observations, can have significant differences in the lengths of different rays. What in heraldry is 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 wind direction, can demonstrate the frequency of winds (discretized according to a certain criterion - 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, which will contain diagrams of two or more parameters. The examples below show different ways to read the diagrams:

Eight-pointed compass rose

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

16-ray compass rose

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

360-ray compass rose

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

Compass rose with numerical values ​​and additional notes

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 during 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 diagram characterizes the number of windless 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 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, northeastern winds in the Northern Hemisphere and southeastern winds in the Southern Hemisphere. 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 can carry dust from African deserts to the West Indies and some areas of North America.

Circulation processes of the Earth that lead to wind formation

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 the seasonal winds that blow from the Indian Ocean and Arabian Sea to the northeast, bringing significant amounts of 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 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 Earth's oceans.

Passat(from Spanish viento de pasada - wind favorable for moving, movement) - wind blowing between the tropics all year round, in the Northern Hemisphere from the north-east, in the Southern - from the south-east, separated from each other by a windless strip. On the oceans the trade winds blow with the greatest regularity; 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.

Map of winds 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 for constructing ship routes between Europe and the New World.

Due to the action of the sun's rays in the equatorial zone, the lower layers of the atmosphere, heating up more, rise upward and tend towards the poles, while new colder air currents arrive below from the north and south; Due to the daily rotation of the Earth according to the Coriolis force, these air currents take a direction towards the southwest (northeast trade wind) in the Northern Hemisphere, and a northwest direction (southeast trade wind) in the Southern Hemisphere. The closer any point on the globe lies to the pole, the smaller the circle it describes per day, and therefore, the less speed it acquires; Thus, air masses flowing from higher latitudes, having a lower speed than points on the earth's surface on the equatorial strip, rotating from west to east, must lag behind them and, therefore, flow from east to west. In low 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 latitude. and 10° S the inflowing layers of air, in contact with the earth's surface, acquire the speed of the latter's points; As a result, near the equator, the northeast trade wind again takes an almost northern direction, and the southeast trade wind almost south and, mutually meeting, give a strip of calm. In the trade wind zone between 30°N. and 30° S In each hemisphere, two trade winds blow: in the Northern Hemisphere, the northeast wind is below, the southwest wind is above, in the Southern Hemisphere, the southeast wind is below, and the northwest wind is above. The upper current is called anti-passat, anti-pass wind, or upper trade wind. Beyond 30° north and south latitude. the upper, coming from the equator, layers of air descend to the surface of the earth and the regularity of the equatorial and polar currents ceases. From the polar boundary of the trade wind (30 °), part of the air mass returns to the equator as the lower trade wind, and the other part flows to higher latitudes and appears in the Northern Hemisphere as a southwest or west wind, and in the South as a northwest or west wind .

When relatively cold air masses from temperate latitudes enter the subtropics, the air is heated and powerful convective currents develop (air masses rise) at a rate 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 retards the development of clouds, so there is very little precipitation. Fine rainfall occurs only occasionally.

Lower trade winds between the tropics; on the Atlantic and Pacific oceans, were known to ancient sailors. The satellites 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 Hadley (1735). The windless strip moves north or south, depending on the state of the sun at the equator; in the same way, the boundaries of the trade wind region change both in the north and in the south at different times of the year. In the Atlantic Ocean, the northeast trade wind blows in winter and spring between 5° and 27° N, and in summer and autumn between 10° and 30° N. The southeast 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 southerly and southwesterly wind. The area of ​​calm between the trade winds in the Atlantic Ocean lies north of the equator and in December and January is 150 nautical miles wide, and in September 550 miles. IN Pacific Ocean the equatorial boundaries of the trade wind region 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 over vast expanses of water, and this explains the fact that it enters the northern hemisphere.

Monsoon(from Arabic موسم (“māvsim”) - time of year, via 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 countries of the temperate zone ( Far East). The monsoon climate is characterized by high humidity in the summer.

At each location in 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 the opposite. Thus, in each monsoon region there are summer and winter monsoons with mutually opposite or at least sharply different prevailing directions.

Of course, in addition to the winds of the prevailing direction, winds of other directions are also observed in each season: the monsoon experiences interruptions. During the transition seasons, spring and autumn, when the monsoons change, the stability of the wind regime is disrupted.

The stability of monsoons is associated with a stable distribution of atmospheric pressure during each season, and their seasonal change is associated with fundamental changes in the distribution of pressure from season to season. The prevailing baric gradients change direction sharply from season to season, and 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 the distribution does not at all mean that the same anticyclone or the same depression remains over a given area during the season. For example, in winter a number of anticyclones successively change over East Asia. 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 appears on the long-term average climate map. Northern wind directions associated with the eastern peripheries 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 one over the other. In those areas of the Earth where cyclones and anticyclones quickly replace each other and little 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). Monsoons have the greatest stability 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, the Gulf of Mexico, eastern Asia, South America, southern Africa and Australia).

Above the ridge Vindhya (India)

Kolkata (India)

Arizona (USA)

Darwin (Australia)

Temperate westerly winds— prevailing winds blowing in the temperate zone between approximately 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 predominantly from west to east, more specifically from the southwest in the Northern Hemisphere and from the northwest in the Southern Hemisphere, and can form extratropical cyclones at their margins where the wind speed gradient is high. Tropical cyclones that enter these winds through the subtropical ridge lose strength and are strengthened again by the speed gradient of the temperate westerly winds.

Map of trade winds and temperate westerlies

Westerly winds in the temperate zone blow stronger in winter, when pressure over the poles is lower, and weakly in summer. These winds are strongest in the Southern Hemisphere, where there is less land to deflect or block the wind. A band of strong temperate westerlies located between 40 and 50 degrees south latitude and 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 the continents, especially in the Southern Hemisphere.

Benjamin Franklin's map of the Gulf Stream

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

These winds are usually weaker and less regular than the westerly winds of temperate latitudes. Due to the low amount of solar heat, the air in the polar regions cools and sinks, creating areas of high pressure and pushing subpolar air towards lower latitudes. This air, as a result of the Coriolis force, is deflected to the west, forming northeastern winds in the Northern Hemisphere and southeastern winds in the Southern Hemisphere.

Local effects of wind formation arise depending on the presence of local geographical objects. One such effect is a 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 strongest between land and water and causes a breeze. 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 some way from the main character of the general circulation of the atmosphere, but, like constant winds, regularly repeat and have a noticeable impact 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, fön, dry wind, simoom and many others.

The occurrence of local winds is mainly due to the difference temperature conditions over large bodies of water (breezes) or mountains, their extension relative to general circulation flows and the location of mountain valleys (fen, bora, mountain-valley), as well as with changes in the general circulation of the atmosphere by local conditions (samum, sirocco, khamsin). 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 classified as local winds and given their own names.

For example, only on Baikal, due to the difference in heating of water and land and the complex arrangement of steep ridges with deep valleys, at least 5 local winds are distinguished: Barguzin - a warm northeastern wind, mountain - a northwestern wind that causes powerful storms, sarma - a sudden westerly wind, reaching hurricane force up to 80 m/s, valley ones - southwestern kultuk and southeastern shelonik.

Afghan

Afghan - a dry, baking local wind, with dust, that 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's called kara-buran, which means black storm or shuravi bodysuit - Soviet wind.

Biza

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

Bora

Bora (Italian bora, from Greek. βορέας - North wind; “borei” - cold north wind) - a strong cold gusty local wind that occurs when a flow of cold air encounters a hill on its way; Having overcome the obstacle, the bora hits the coast with enormous force. The vertical dimensions of the bora are several hundred meters. As a rule, it affects small areas where low mountains directly border the sea.

Scheme of bora occurrence

In Russia, the 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 Olkhon Gate Strait), and the Chukotka city of Pevek (the so-called “yuzhak”) are especially strong. ).

Consequences of bora, Novorossiysk, November 11, 1993.

Shipwreck as a result of bora, Novorossiysk, 1993.

Novorossiysk, 1997

In Europe, the most famous are the forests of the Adriatic Sea (in the area of ​​​​the cities of Trieste, Rijeka, Zadar, Senj, etc.). In Croatia they call the wind bura. The “nord” wind in the Baku region, the mistral on the Mediterranean coast of France from Montpellier to Toulon, and the “north ser” in the Gulf of Mexico are also similar to bora. The duration of the bora is from a day to a week. The daily temperature difference during bora can reach 40°C.

Bora

Bora occurs in Novorossiysk and the Adriatic coast in cases where 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 falls down the mountain range, while gaining greater speed.

Before the appearance of the bora, thick clouds can be observed at the tops of the mountains, which the residents of Novorossiysk call "beard". Initially, the wind is extremely unstable, changing direction and strength, but gradually acquires a certain direction and enormous speed - up to 60 m/s at the Markotkhsky pass near Novorossiysk. In 1928, a wind gust of 80 m/s was recorded. On average, the wind speed during boron reaches more than 20 m/s in the Novorossiysk region in winter. Falling on the surface of the water, this downdraft generates gale force winds, causing strong rough seas. At the same time, the air temperature drops sharply, which was above warm sea quite high.

Sometimes boron causes significant destruction in the coastal strip (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 cause destruction; at 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, 10-15 kilometers deep into the sea, on the Adriatic, at some synoptic positions, it covers a significant part of the sea).

The varieties of bora are Tramontana, sarma.

Tramontana (Italian tramontana - “from behind the mountains” ) - cold north and northeast wind in Italy, Spain, France and Croatia. It is a type of Bora wind. Occurs due to 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 varies 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 mountainous region 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: the daytime (or sea) breeze blows from the sea onto the coast, warmed by the daytime rays of the Sun. The night (or shore) breeze has the opposite direction.

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

The breeze speed is small, 1-5 m/s, rarely more. A breeze is noticeable only in conditions of weak general air transport, as a rule in the tropics, and in mid-latitudes - in stable windless 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 a reverse current - antibreeze. Breeze circulation affects areas of the coast and sea 10–50 km wide. Sea breezes lower the air temperature during the day and make the air more humid. Breeze occurs more often in summer, when the temperature difference between land and water reaches its 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.

Föhn (German Fohn, 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 the highlands quickly falls down through relatively narrow intermountain valleys, which leads to its adiabatic heating. When descending for every 100 m, the air warms up by about 1°C. Descending from a height of 2500 m, it heats up by 25 degrees and becomes warm, even hot. Usually the hairdryer lasts less than a day, but sometimes the duration reaches 5 days, and changes in temperature and relative humidity can be rapid and abrupt.

Hairdryers are especially frequent in spring, when the intensity of the general circulation of air masses sharply increases. Unlike a foehn, bora is formed when masses of dense cold air invade.

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

(To be continued)