Plan:

Introduction

• 1 Afghan
• 2 Barguzin
• 3 Bizet
• 4 Bora
• 5 Breeze
• 6 Garmattan
• 7 Garmsil
• 8 Mountain-valley winds
• 9 Marshmallow
• 10 Mistral
• 11 Pampero
• 12 Shoulder straps
• 13 Samum
• 14 Sarma
• 15 Sirocco
• 16 Sukhovey
• 17 Tornado
• 18 Föhn
• 19 Khamsin
• 20 Chinook

Introduction

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 a breeze that changes its direction twice a day, mountain-valley winds, bora, foehn, dry winds, samum and many others. The occurrence of local winds is associated mainly with the difference in 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 (the very , 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 North-Eastern, mountain - North-Western wind, causing powerful storms, Sarma - a sudden Western wind, reaching hurricane force up to 80 m/s, valley ones - South-Western kultuk and South-Eastern shelonik.

1. Afghan

Afghan is 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 is called kara-buran, which means black storm or body shuravi - Soviet wind.

2. Barguzin

Barguzin - the mighty Baikal wind, mentioned in the song “The Glorious Sea - Sacred Baikal”, blows mainly in the central part of the lake from Barguzin Valley across and along Lake Baikal. This wind blows evenly, with gradually increasing power, but its duration is noticeably shorter than that of Verkhovik. Usually preceded by stable sunny weather.

3. Bizet

Bizet (French Bise) is a cold and dry north or northeast wind in the mountainous regions of France and Switzerland. Bizet is similar to the Mistral.

4. Bora

Bora (Italian bora from the Greek boreas - north wind) is a strong gusty cold wind blowing on the coast of seas or large lakes from mountain ranges that separate the very cool and warmer (especially coastal) surface at their feet. It is formed when low mountain ranges separate cold air over land from warm air over water. This wind is most dangerous in frosty weather, when it rolls down mountain ranges at high speed (up to 40-60 m/s) to a sea or lake that has not yet frozen. Over a warm water surface, the temperature contrast between the flow of cold air and the warm sea increases significantly, and the speed of the bora increases. A squally wind brings severe cold, raises high waves, and splashes of water freeze on the hulls of ships. Sometimes a layer of ice up to 4 meters thick grows on the windward side of the ship, under the weight of which the ship can capsize and sink. The bora lasts from several days to a week. The bora is especially typical on the Yugoslav coast of the Adriatic Sea, near Novorossiysk (northeast wind), on the western slope of the Urals - the eastern Kizelovskaya bora and others. A special type of bora is the katabatic wind in Antarctica and on the northern island of Novaya Zemlya.

5. Breeze

Breeze (French brise - light wind) is a local wind of low speed, changing direction twice a day. It occurs on the shores of seas, lakes, and sometimes large rivers. During the day, land heats up faster than water, and a lower temperature is established above it. Atmosphere pressure. Therefore, the daytime breeze blows from the water area to the heated coast. Night (shore) - from the cooled coast to warm water. Breezes are well expressed in summer during stable anticyclonic weather, when the difference in temperature between land and water is most significant. Breezes cover a layer of air of several hundred meters and on the seas operate within a range of several tens of kilometers. In the era of sailing, breezes were used to begin sailing.

6. Garmattan

Harmattan - dry and sultry wind, blowing on the Guinea coast of Africa and bringing red dust from the Sahara.

7. Garmsil

Garmsil (Taj.Garmsel) is a dry and hot wind like a foehn, blowing mainly in summer from the south and southeast in the foothills of the Kopetdag and Western Tien Shan.

8. Mountain-valley winds

Mountain-valley winds form in mountainous areas and change their direction twice a day. The air is heated differently over the crests of mountain ranges, slopes and valley floors. During the day, the wind blows up the valley and slopes, and at night, on the contrary, from the mountains into the valley and down towards the plain. The speed of mountain-valley winds is low - about 10 m/s.

9. Marshmallow

Zephyr (Greek Ζέφυρος, “western”) - the wind prevailing in the eastern part Mediterranean Sea, starting in spring, and reaching its greatest intensity by the summer solstice. Here, although it is warm, it often brings with it rain and even storms, while in the western part of the Mediterranean Sea Zephyr is almost always a light, pleasant wind.

10. Mistral

On the Mediterranean coast of France, the cold north-west wind, formed like the Novorossiysk bora, is called mistral, and a similar wind on the coast of the Caspian Sea in the Baku region is called north.

11. Pampero

Pampero (Spanish: Pampero) is a cold, stormy (sometimes with rain) south or southwest wind in Argentina and Uruguay. Pampero is associated with incursions of Antarctic air.

12. Shoulder strap

Shoulder strap - there is a fair wind on the Volga.

13. Samum

Samum is a sultry dry wind in the deserts of North Africa and the Arabian Peninsula. Usually, before the approaching squall of a simoom, the sands begin to “sing” - the sound of grains of sand rubbing against each other is heard. Raised “clouds” of sand obscure the Sun. Samum occurs when the earth and air are strongly heated in cyclones and mainly during western and southwestern winds. The wind carries hot sand and dust and is sometimes accompanied by a thunderstorm. The air temperature can rise to +50 °C, and the relative humidity approaches 0%. The squall lasts from 20 minutes to 2-3 hours, sometimes with a thunderstorm. When doing samum, you should lie down and cover yourself tightly with clothes. In the Algerian Sahara it happens up to 40 times a year.

14. Sarma

On Lake Baikal, the boron has a local name - sarma. This wind is formed when cold arctic air passes over the coastal mountain ranges. It is named after the Sarma River, through the valley of which the cold wind from Yakutia breaks through to Baikal. In 1912, this icy wind tore a huge barge from its tug and threw it onto a rocky shore. As a result, more than 200 people died.

15. Sirocco

Sirocco (Italian Scirocco - strong) is a hot, dry, dusty south and southeast wind from the deserts of North Africa and the Arabian Peninsula, occurring in the front of the cyclone. Over the Mediterranean Sea, sirocco is slightly enriched with moisture, but still dries out the landscapes of the coastal regions of France, the Apennine and Balkan peninsulas. Most often it blows in spring for 2-3 days in a row, raising the temperature to 35 °C. Crossing the mountains, on their leeward slopes it acquires the character of a foehn.

16. Sukhovey

Dry wind is a wind with high temperature and low relative humidity in steppes, semi-deserts and deserts; it forms along the edges of anticyclones and lasts for several days, increasing evaporation, drying out the soil and plants. The speed of the dry wind is usually moderate, the relative humidity is low (less than 30%). Dry winds are characteristic of the steppe regions of Russia and Ukraine, Kazakhstan and the Caspian region.

17. Tornado

Tornado (Spanish: Tornado) - in North America, a strong atmospheric vortex over land, characterized by exceptionally high frequency, is formed as a result of the collision of cold masses from the Arctic and warm masses from the Caribbean. Several hundred tornadoes occur in the eastern United States each year.

18. Hairdryer

Foehn (German Fohn, from Latin Favonius - warm western wind) is a dry, warm strong wind blowing gustily from high mountains to valleys. It is observed in all mountainous countries. The air flows over the crest of the ridge, rushes along the leeward slope into the valley, and as it descends, its temperature rises and humidity decreases as a result of adiabatic heating - by one degree for every 100 m of descent. The greater the height from which the foehn descends, the higher the temperature of the air it brings rises. The speed of the hair dryer can reach 20-25 m/s. In winter and spring, it causes rapid melting of snow, disappearance of valleys, increased evaporation from soil and vegetation cover, and the level of mountain rivers. In summer, its drying breath is destructive to plants; Sometimes in Transcaucasia, the summer foehn causes the foliage on the trees to dry out and fall off. Usually lasts less than a day, occasionally up to 5 or more. Föhn is well expressed in the Alps, the Caucasus, and the mountains of Central America.

19. Khamsin

Khamsin (Arabic literally fifty) is a dry, swelteringly hot wind from the south in northeast Africa and the Middle East. The air temperature is often above 40 °C; with gale force winds, khamsin sometimes blows 50 days a year, usually in March-May. Occurs at the front of cyclones moving from the deserts of North Africa, so khamsin is filled with sand and dust, reducing visibility.

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MINISTRY OF TRANSPORT OF THE RUSSIAN FEDERATION

FEDERAL STATE BUDGET EDUCATIONAL INSTITUTION OF HIGHER EDUCATION

“ULYANOVSK INSTITUTE OF CIVIL AVIATION NAMED AFTER CHIEF MARSHAL OF AVIATION B.P. BUGAEV"

Department of Air Traffic Control and Navigation

Academic discipline: “Aviation Meteorology”

on the topic: “Local winds”

Completed by: cadet study group D-14-2

Kulagin Yu.V.

Checked by: senior teacher Department of ATC and N Buzaeva S.V.

Ulyanovsk 2016

1. Local winds

wind atmosphere sirocco

Local winds are 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 a breeze that changes its direction twice a day, mountain-valley winds, bora, foehn, dry winds, samum and many others.

The occurrence of local winds is associated mainly with the difference in 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 (the very , 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, on Baikal alone, 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 - warm northeastern, mountain - northwestern wind, causing powerful storms, Sarma - sudden western wind, reaching hurricane force up to 80 m/s, valley winds - southwestern kultuk and southeastern shelonik.

Bora (Italian bora, from the Greek vpsEbt - north wind; “boreas” - cold north wind) is 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.

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. ). 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 the wind is called boomra. 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.

Scheme of bora occurrence

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 flows down the mountain range, acquiring 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 before the start of the bora was quite high over the warm sea.

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; during severe frosts (in Novorossiysk about? 20...? 24 °C) they freeze and an ice crust forms (on the Adriatic the only place where an ice crust forms is the city of Senj). Sometimes 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).

3. Mistral

Mistral (French mistral) is a cold northwest wind that blows from the Cevennes to the Mediterranean coast of France in the spring months and is a real scourge Agriculture the Rhone Valley and all of Provence. The mistral is a type of katabatic wind. Often the wind is so strong that it uproots trees. In any case, its constant influence is noticeable on solitary trees, which are often tilted to the south.

In the eastern part of the Cote d'Azur, the effect of the mistral is much weaker.

The Mistral is formed when the Atlantic anticyclone and the North Sea cyclone meet.

A tree grown in a constantly blowing mistral.

4. Pampero

Pampero (Spanish pampero, plural pampemros - “wind from the pampa”) is a cold stormy south or southwest wind in the eastern part of Argentina, Uruguay and Paraguay, sometimes with rain. Associated with incursions of Antarctic air.

They usually occur suddenly after warm northern winds, carry clouds of dust and are accompanied by a rapid increase in pressure and a decrease in temperature. Their properties are quite consistent with the cold, dry northwest winds off the eastern coasts of Asia and North America. On the shore, pampero is often replaced by cold and strong, but humid, southeast winds. In open space, wind speed reaches 25 m/s.

The first stage is usually called Pampero Hamedo (“wet pampero”), bringing showers and snowfall, and the second stage is Pampero Seco (“dry pampero”), which turns into the dust storm Pampero Sucio. Although pampero can occur at any time of the year, it is usually worst during the early summer in the Southern Hemisphere, between October and January.

Dry cold diapers are carried great amount dust and small pebbles. Due to wind-driven storms, shipping is difficult off the coast of Patagonia. Pampero, as well as the sultry north wind “norte”, blow away the soil layer, forming dune areas.

Föhn (German Föhn, from Latin 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 approximately 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.

6. Sirocco

Scirocco is rarely scirocco, (Italian scirocco, from Arabic FSUE - sharq - east) - a strong south or southwest wind in Italy, and this name is also applied to the wind of the entire Mediterranean basin, originating in North Africa, the Middle East and having its own name and its own characteristics in different regions.

The difference between this regular air flow in some ways and the main character of the general circulation of the atmosphere, as well as a noticeable influence on the weather regime in the Mediterranean region, makes it possible to classify the sirocco as a local wind. The direction is south, southeast or east (sometimes even southwest). In the centers of formation, and when it passes through the mountains in southern Europe, on the leeward side it acquires the character of a foehn. Occurs at all times of the year; in summer - less often, in spring and autumn - more often. It reaches its greatest strength in March and November. In some regions, it sometimes reaches speeds of up to 100 km/h (55 knots - hurricane force), reaching gale force (from 2 to 9 on the Beaufort scale), although in some places it is considered a moderate wind. Usually worsens in the afternoon, and weakens in the evening and at night. It blows for 2-3 days in a row, but can last half a day or many days. It has a depressing effect on people.

Sirocco originates in the depths of the Arabian and North African deserts. It originates in warm, dry, tropical air masses that move north toward low pressure eastward across the Mediterranean Sea. Hot, dry continental air mixes with cooler, wetter air from the offshore cyclone and moves counterclockwise toward the southern coast of Europe. On its way through the Mediterranean Sea, it becomes more humid, but nevertheless often dries out the vegetation of southern Europe, also bringing large masses of dust.

The sirocco is generally considered to be a stifling, scalding, very dusty wind with high temperatures (up to 35 °C at night) and low relative humidity (see dry wind), however, in some areas of the Mediterranean it is a warm, moist sea wind. It sometimes causes dusty, dry weather along the northern coast of Africa, storms in the Mediterranean and cold, wet weather in Europe. It causes dry fogs and dusty haze.

Dust brought by sirocco can damage mechanical devices and enter living spaces. Sirocco is unhealthy regardless of whether it is wet or dry. Some sirocco cause nervous disorders, headaches, neuralgia, weakness, sleep disturbances, increased irritability, etc., even to the point of insanity. There are even legends that crimes committed during the sirocco were once forgiven, being attributed to its maddening dryness and heat.

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Local winds are winds that are characteristic of certain geographical areas and are associated in their origin with local conditions. The cause of local winds may be uneven heating of the air from the underlying surface (breezes, mountain-valley winds).

Breezes occur on the shores of seas, large lakes and some large rivers and are characterized by a sharp change in direction during the day.

During the day, when the land is heated more than the water, the air above it rises and flows upward towards the reservoir. In the surface layers, the wind begins to blow from the sea to the land - the sea breeze. The air flowing towards land is compensated by its descent over the sea. Onshore breezes occur at night when the land cools more than the water and when the air circulation is opposite to that of the day. With rising currents (over land during the day, over water at night), clouds form. During downward currents the sky is cloudless.

Since the contrasts in temperatures between land and water are greater during the day than at night, sea breezes are more pronounced than coastal breezes: their speed is greater (up to 7 m/sec), their power is greater (up to 1000 m), and the wind they capture is wider (up to 100 km).

Breezes are especially pronounced where daily temperature fluctuations are large, for example in the tropical zone.

Mountain-valley winds can be divided into two types: slope winds and mountain-valley winds themselves. Slope winds arise as a result of different heating and cooling of air at the same level at the surface of the slope and in the free atmosphere. During the day, the air near the slopes heats up more than the air at the same level further away from the slope, resulting in upslope winds. At night the opposite is true.

Actually, mountain-valley winds are caused by the fact that the air in a mountain valley heats up and cools more than at the same altitude above the neighboring plain. During the day it rises along the bottom of the valley (valley wind), at night it flows down (mountain wind).

Local winds (foehn, bora), arising as a result of the influence of relief on air currents, with a certain pressure distribution are called orographic.

Föhn is a warm, dry and gusty wind from mountains, often covered with snow and glaciers. It occurs when there is a large difference in atmospheric pressure on one side and the other side of a mountain range. Passing over the ridge to the side low blood pressure, the air on the windward slope cools (by 1° per 100 m before the condensation limit and by 0.5-0.6° per 100 m above the condensation limit) and loses moisture (clouds form and precipitation occurs). At the pass altitude, the air has a correspondingly lower temperature and absolute humidity than at the beginning of the rise, which coincides with the maximum moisture content at a given temperature. On the leeward slope, the air, descending, heats up adiabatically (by 1° per 100 m) and moves away from the saturation point, acquiring features characteristic of a foehn (relatively high temperature and low relative humidity).

The foehn blows often in winter and spring. With a large deficit of air humidity, it causes rapid melting and evaporation of snow (the hairdryer is called the “snow eater”), and in the spring it has a drying effect on plants. The duration of the hair dryer is from several hours to several days, the speed is from calm to 20% m/sec. Hair dryer is very common. In Russia and neighboring countries it can be observed in the Caucasus, in the mountains of Central Asia, and in Yakutia.

Bora is a cold strong wind blowing from low (up to 1000 m) coastal mountains towards the sea, mainly in the cold season. Bora occurs when cold air over land is separated from warm air over water by a low ridge. Cold air gradually accumulates in front of the ridge and rolls down to the sea at high speed. As it descends, it heats up adiabatically, but the temperature difference between cold and warm air still remains large. As a result, the temperature on the coast drops sharply.

The Novorossiysk bora has been well studied. Through the Markhot Pass (450 m) on the Varada ridge, a mass of cold air rushes to the Black Sea from the land side. Wind speed reaches 40 m/sec, in some cases - 60 m1sec. The temperature on the seashore sometimes drops to -20.-25°. The spray of water caused by the wind freezes, and a layer of ice up to 4 m thick quickly covers the embankment, various objects on the shore and ships at sea. Since bora appears in the sea at a distance of no more than 3-5 km, ships are in a hurry to leave the bay.

Local winds refer to winds that are characteristic only of certain geographical areas. Their origin is different.

Firstly, local winds may be a manifestation of local circulations, independent of the general circulation of the atmosphere and superimposed on it. Such are, for example, breezes along the shores of seas and large lakes. Differences in the heating of the shore and water during the day and night create local circulation along the shoreline. At the same time, in the surface layers of the atmosphere, the wind blows during the day from the sea to the warmer land, and at night, on the contrary, from the cooled land to the sea. Mountain-valley winds also have the character of local circulation. See below for more details.

Secondly, local winds can represent local changes (disturbances) in the currents of the general circulation of the atmosphere under the influence of orography or topography of the area. Such, for example, is the foehn - a warm wind blowing along mountain slopes into valleys when the current of the general circulation crosses a mountain range. The downward movement of the foehn, associated with an increase in air temperature, is a consequence of the influence of the ridge on the general circulation flow. The influence of orography also explains boron and its various varieties.

Terrain may also cause winds to increase in some areas to speeds significantly higher than those in neighboring areas. Such locally enhanced winds of one direction or another are also known in different areas under different names like local winds. Sometimes special properties are given to the local wind by the passage of air over a very hot and dry surface, such as a desert, or, conversely, over a highly evaporating (water) surface.

Thirdly, local winds also refer to such strong winds or winds with special properties in a certain area, which are essentially general circulation currents. The intensity of their manifestation and their specificity for a given geographical area are a consequence of the general circulation mechanism itself, the very geographical distribution of synoptic processes. In this sense it is called a local wind, for example, the sirocco on the Mediterranean Sea.

In addition to the sirocco, numerous local winds are known in various places on the Earth, bearing special names, such as samum, khamsin, Afghan, etc. Mention of such winds can be found in the physiographic or climatic characteristics of individual areas.

Breezes are winds near the coastlines of seas and large lakes that have a sharp daily change in direction. During the day, the sea breeze blows in the lower few hundred meters (sometimes in a layer of more than a kilometer) towards the shore, and at night the shore breeze blows from the shore to the sea. Wind speed during breezes is about 3-5 m/sec, in the tropics and more. Breezes are clearly expressed in cases where the weather is clear and the general air transport is weak, as happens, for example, in the inner parts of anticyclones. Otherwise, the general movement of air in a certain direction masks the breezes, as always happens during the passage of cyclones.

Particularly pronounced breeze circulation is observed in subtropical anticyclones, for example on desert coasts, where daily temperature changes over land are large and overall pressure gradients are small.

But well-developed breezes are observed in the warm season (from April to September) and in such mid-latitude seas as the Black, Azov, and Caspian.

Breezes are associated with the daily variation of land surface temperature

Mountain-valley winds

In mountain systems, winds with a daily frequency, similar to breezes, are observed. These are mountain-valley winds. During the day, the valley wind blows from the throat of the valley up the valley and also up the mountain slopes. At night, the mountain wind blows down the slopes and down the valley towards the plain. Mountain-valley winds are well expressed in many valleys and basins of the Alps, Caucasus, Pamirs and other mountainous countries, mainly in the warm half of the year. Their vertical power is significant and measured in kilometers: the winds fill the entire cross-section of the valley, right up to the crests of its side ridges. As a rule, they are not strong, but sometimes reach 10 m/sec or more.

A foehn is a warm, dry and gusty wind that sometimes blows from the mountains to the valleys. The air temperature with a hairdryer increases significantly and sometimes very quickly; relative humidity drops sharply, sometimes to very low values. At the beginning of the foehn, sharp and rapid fluctuations in temperature and humidity can be observed due to the meeting of the warm air of the foehn with the cold air filling the valleys. Foehn gustiness indicates strong turbulence in the foehn flow. The duration of the hairdryer can be from several hours to several days, sometimes with interruptions (pauses).

Hairdryers have been known in the Alps since ancient times. They are very common in the Western Caucasus, both on the northern and southern slopes of the ridge.

A prolonged and intense foehn can lead to rapid melting of snow in the mountains, an increase in the level and overflow of mountain rivers, etc. In the summer, the foehn, due to its high temperature and dryness can have a detrimental effect on vegetation. In the Transcaucasus (Kutaisi region) it happens that during summer hair dryers the foliage of trees dries out and falls off.

But a hair dryer can also be observed in Arctic air, when the latter, for example, flows through the Alps or the Caucasus and falls along the southern slopes. Even in Greenland, the flow of air from a three-kilometer-high ice plateau onto the fiords creates very strong temperature increases. In Iceland, temperature rises of almost 30° in a few hours were observed with hairdryers.

When the ridge flows in an air current, standing waves, so-called foehn waves, with an amplitude of several kilometers can arise, sometimes leading to the formation of lenticular clouds. These waves propagate upward to a height several times greater than the height of the ridge.

Bora is a strong cold and gusty wind blowing from low mountain ranges towards a fairly warm sea. Bora has long been known in the area of ​​Novorossiysk Bay on the Black Sea and on the Adriatic coast of Yugoslavia, in the Trieste region. Similar phenomena were discovered on Novaya Zemlya and in some other places. Sarma near the Olkhon Gate on Lake Baikal also belongs to the type of bora. Nord in the Baku region, Mistral on the Mediterranean coast of France, from Montpellier to Toulon, and North in the Gulf of Mexico (Mexico, Texas) are quite similar to bora in origin and manifestations.

Bora occurs in Novorossiysk, as in the Adriatic, in cases where a cold front approaches the coastal ridge from the northeast. Cold air immediately crosses the low ridge. Falling down the mountain ridge under the influence of gravity, the air acquires significant speed: in Novorossiysk in January, the wind speed during boron averages above 20 m/sec. Falling on the surface of the water, this downward wind creates a strong disturbance. At the same time, the air temperature drops sharply, which was quite high over the warm sea before the bora began.

Russia is a big country, and there is plenty of room for the winds to run wild. There are local winds in every region of our country. We remembered the main ones.

Barguzin

The mighty eastern Baikal wind, with a speed of 20 m/s and a duration of only a few hours. It reaches its special power in the fall. It blows mainly in the central part of the lake from the Barguzin Valley across and along Lake Baikal. It occurs due to the flow of cold air from the Daurian steppes. It blows evenly, with gradually increasing power, and usually precedes stable sunny weather.

The glorious sea is sacred Baikal,
A glorious ship is an omul barrel.
Hey, Barguzin, move the shaft,
Well done, it's not far to swim.

Bora

Bora (Italian bora from Greek boreas - north wind) lasts from several days to a week. This is the wind of the Novorossiysk and Gelendzhik bays (blows more than 40 days a year), Novaya Zemlya, the shores of Lake Baikal, the Chukotka city of Pevek ("yuzhak"), the wind of the western slope of the Urals. This is a strong gusty cold wind blowing on the coast of seas or large lakes from mountain ranges that separate the very cool and warmer coastal surface at their feet. It forms when low mountain ranges separate cold air over land from warm air over water. The warmer the water and the greater the temperature contrast, the more powerful the boron. A squally wind brings severe cold, raises high waves, and splashes of water freeze on the hulls of ships. Sometimes a layer of ice up to 4 meters thick grows on the windward side of the ship, under the weight of which the ship can capsize and sink. Before the appearance of the bora, thick clouds can be observed at the tops of the mountains, which the residents of Novorossiysk call “beard”.

Yuzhak

The origin of the name "Yuzhak" is beyond doubt: yuzhak is the general name for the southern winds in Russia. However, the Yuzhak is widespread not only in the southern regions of the country, but also in the northern ones. Thus, the Yuzhak is one of the most dangerous winds in Chukotka. He is dangerous with his suddenness and strength. Within an hour, the wind can blow at a speed of 40 m/s, and gusts can reach 60 - 80 m/s. Yuzhak carries away almost all the snow, exposes the banks, and destroys buildings. It is dangerous for ships anchored in the roadstead. Yuzhak is also called the southwest and west wind in Tiksi Bay. It is also strong and poses a threat to shipping.

Breeze

Breeze (French brise - light wind) is a local wind of low speed, changing direction twice a day. It occurs on the shores of seas, lakes, and sometimes large rivers. During the day, land warms up faster than water, and lower atmospheric pressure sets over it. Therefore, the daytime breeze blows from the water area to the heated coast. Night - from the chilled coast to warm water. Breezes are well expressed in summer during stable anticyclonic weather, when the difference in temperature between land and water is most significant. Breezes blow within a few hundred meters on land, and within a few tens of kilometers on the seas. In the era of sailing, breezes were used to begin sailing.

Sarma

The most powerful wind of both Baikal and Russia. This squally wind is formed when cold arctic air moves over the coastal mountain ranges. It is named after the Sarma River, through the valley of which the cold wind breaks through to Baikal. It appears like this: cold arctic air from the Lena plateau, passing through the Primorsky ridge, enters the Sarma valley, which narrows towards the shore of Baikal, which is a natural wind tunnel, upon exiting which the wind turns into a hurricane. Residents of the village of Sarma have to tie the roofs of their houses to the ground. This wind is most frequent and fierce in autumn and winter: in November - 10 days, in December - 13.

Before the appearance of sarma, mushroom-shaped stratocumulus clouds appear, with sharply defined boundaries, gathering over the peaks of the Primorsky ridge near the Sarma gorge. Usually, 2-3 hours pass from the beginning of the concentration of such clouds to the first gust of sarma. The last sign is the opening of the “gate” - the appearance of a gap between the tops of the mountains and the lower edge of the clouds.