Introduction
Wind is one of the most important characteristics of weather and climate. Wind causes the movement and mixing of air and transports impurities suspended in it. Wind promotes the exchange of heat, moisture and energy between the underlying surface and the atmosphere, and also transports enormous air masses within the general circulation of the atmosphere.
Many natural processes and phenomena are associated with the action of wind. Strong winds cause soil erosion, dust storms and waves on bodies of water, while hurricanes and storms cause destruction and coastal flooding. Wind significantly affects the operation of many sectors of the economy: agriculture, aviation, maritime, river, road and rail transport, municipal services and others.
The Dictionary provides the names and characteristics of winds and wind systems on planetary and local scales, as well as certain synoptic, meteorological, hydrodynamic, technical, geographical and maritime terms and characteristics related to the action of winds.
For ease of use, the terms and concepts in the Dictionary are grouped into two parts: the first, main part gives the names and characteristics of winds and wind systems, as well as some terms related to the genesis of winds; the second part contains meteorological, synoptic, geological and maritime terms and concepts that characterise the effects of winds. In addition, the second part includes some specialised terms needed to understand the main entries in the first part of the Dictionary, as well as geographical names associated with wind.
The Dictionary includes terms and concepts found in various literary sources, both in Russian and in several foreign languages. Encyclopaedic and specialised dictionaries, reference books, textbooks, monographs and individual studies were used in compiling the Dictionary. Materials from the author’s many years of correspondence with meteorological institutions, stations and libraries of the Soviet Union, as well as with the meteorological services of the German Democratic Republic, the People’s Republic of Bulgaria, Japan, the Hawaiian Islands, Sweden, Spain, France and others, were also used.
It should be noted that textbooks on climatology and meteorology and specialised reference works generally contain only very brief information on the main wind systems and winds. The “Meteorological Dictionary” by S. P. Khromov and L. I. Mamontova, the “Geographical Dictionary” by S. V. Kolesnik and others likewise describe only the principal and best-known winds and wind systems. D. Stamp’s “Dictionary of General Geographical Terms” gives the names of some local winds in foreign countries. The USSR has many similar winds that, unfortunately, are mentioned neither in dictionaries nor in textbooks.
However, with the expansion and improvement of the observation system, as well as the development of previously uninhabited territories, meteorologists and weather forecasters in recent years have increasingly focused on local winds as an important factor influencing weather conditions and human production activities.
In compiling the wind characteristics, the author relied on definitions established in Soviet geographical science. Differences in the completeness with which individual terms are presented are due to their differing importance, degree of study and coverage in the literature.
By analogy with other works on winds, the author sought, where possible, to give an idea of the synoptic conditions under which a particular wind arises and to explain the origin of some wind names.
The Dictionary does not claim to be exhaustive. Some definitions may appear subjective; this is due to differences in the views of the authors of various works and monographs from which definitions and spellings of names were taken.
The author expresses deep gratitude to all specialists who kindly responded to his inquiries, read individual sections of the manuscript and made useful comments that helped improve the book. The author would be grateful for any comments, additions or suggestions concerning the content and structure of the Dictionary and asks that they be sent to the author at the Ukrainian Research Institute of the State Committee for Hydrometeorology (252028, Kyiv, 105 Nauky Ave.).
Storm in Odesa, 12 October 2016
Storm in Odesa, 12 October 2016. Photo: Anatolii Venhruk
Wind Names — Letter B
BONENTI, ponente — a damp westerly black wind on the Black Sea, in Bulgarian ports and along the Crimean coast, accompanied by overcast weather, sometimes with rain. See Karadzhol, Ponend, Popiete.
BORVII (Ukr.) — a cold northerly wind in Ukraine.
BREEZE
Breeze (English breeze, Spanish/Portuguese brisa) — a light wind, usually up to force 4 on the Beaufort scale, along the coast of a large body of water (large lakes, reservoirs, rivers or seas), which changes direction during the day according to changes in the direction and magnitude of the horizontal temperature gradient across the shoreline, in proportion to the land–water temperature difference. A breeze is usually well developed in the warm season under lightly clouded skies, when the land–water temperature contrast is greatest, around 20 °C.
Daytime (sea, lake) and night-time (land) breezes are distinguished.
The daytime breeze blows from the body of water toward the warmer land (see Sea Wind). The night-time breeze blows from the shore, cooled at night, toward the warmer water surface (see Land Breeze). The land breeze changes to a sea breeze in the morning before noon, while the sea breeze changes to a night-time breeze in the evening, after midday. The height of the air layer affected by the breeze varies depending on synoptic conditions, season and shoreline features. For example, a sea breeze in Sevastopol and Feodosiia can reach a vertical extent of up to 2 km, whereas in Poti it is only about 200 m. The night-time wind can immediately form in a layer up to 300 m thick as air collapses from the land, especially when it combines with a night-time mountain wind from steep coastal slopes. The breeze extends up to 30–40 km from the shoreline.
Above the breeze, a wind in the opposite direction may occur — an antibreeze, separated from the near-water air flow, the breeze itself, by a breeze inversion. The breeze is well developed at low latitudes in summer. It is observed mainly during anticyclonic weather in the evening, when the land breeze is strengthened by the drainage of cooled air from the mountains. Depending on atmospheric circulation and coastal relief, the breeze may strengthen or weaken.
Sometimes the boundary of the breeze’s spread can be traced — the breeze front. The sea-breeze front is the zone where cold marine air meets warm air over land. As the breeze strengthens, this zone moves inland. It is identified by abrupt changes in temperature, humidity and wind and moves bands of morning fog inland (see Fog Wind). The land-breeze front is the zone between continental air that has moved over the sea surface at night and air of marine origin. In the mixing layer at the boundary of these air masses, warm air is buoyant relative to cold air.
Diagram of the formation of daytime and night-time breezes and the vertical distribution of air temperature above the shore in the morning (1) and at the end of the day (2).
Diagram of the development of breeze circulation over river banks. 1 — river breeze, 2 — antibreeze, 3 — general air flow in the lower troposphere, 4 — temperature inversion and wind-reversal level.
Local features can strengthen or weaken breezes. Thus, on the coasts of Portugal and Morocco, the breeze is strengthened by the cold Atlantic current, which increases temperature gradients in the coastal strip. The same occurs in plains close to the sea that are strongly heated by the Sun, for example around Rome and Naples. On the southern and eastern coasts of the Mediterranean, from Tunisia to Syria, breezes occur on almost every summer day, as they do on the coasts of the Black and Azov seas. They intensify when their direction coincides with the general wind flow.
Depending on wind speed, light, gentle, moderate and fresh (strong) breezes are distinguished, with wind speeds of up to 3.3, 5.2, 7.4 and 9.8 m/s respectively.
In a number of coastal areas, “breeze” is a proper name for winds of certain directions and properties. For example, briza (Spanish, Portuguese briza, brisa) is a breeze in Puerto Rico, a regular north-easterly trade wind that changes to an easterly direction under the influence of a latitudinal shoreline; briza carabinera (Spanish briza carabinera) is an unexpected strong coastal squall in Spain and France; brisas is a strong south-easterly sea wind (see Suestado) in Montevideo, Uruguay, as well as a north-easterly trade wind on the coasts of South America during the trade-wind season; breiz (brisa) is the north-easterly monsoon in the Philippine Islands; brisote, brisol (Spanish brisote, brisol) is a north-easterly wind in Cuba, a strong trade wind; brise solaire (French brise solaire) is a breeze in Provence; after sunrise it has a north-easterly direction, by noon it strengthens and turns south-easterly, marking the start of the sea breeze, and then southerly. By evening this wind subsides (see Solaris).
BUENTO-GARBI, punento-garbi — a south-westerly wind in Yalta. It affects the sea current in the bay. Compare Ponend.
BUNENT — a westerly wind on the Sea of Azov. Compare Ponend.
BUREVII (Ukr.) — a hurricane in Ukraine. Compare Borvii.
STORM-FORCE WIND — a wind with a speed of 15 m/s or more lasting more than 2 minutes.
STORM, buron (Uzbek), boroon chapkyn (Kyrgyz), tufon (Tajik), fyrtina (Azerbaijani) — a prolonged and strong wind, 24–28 m/s, accompanied by destruction on land and heavy seas (a storm at sea). On the Beaufort scale, a storm can reach force 10. Such a wind destroys buildings and uproots trees. Dust and dust-free storms are distinguished. Depending on the colour of the lifted dust, dust storms may be black, yellow, red, white or brown. By structure, storms are divided into flow, jet and vortex storms. Storms are usually caused by the passage of an active atmospheric front, a deep cyclone or a tornado.
BUCHNYI RAIN — a storm with heavy rain in Ukraine.
Wind Names — Letter V
VERKHOVYCH — a southerly wind on the Pechora River.
VERKHOVNA — 1. A fresh sea wind usually northerly on the Black Sea. 2. A strong wind on a clear day, a sign of impending bad weather in Krasnoyarsk Krai. 3. A rise in water caused by wind set-up, tide or rain at river mouths and in bays.
UPSTREAM WIND — verkhovyk, verkhovyi, verkhnii, verkhovochka, amon (French), halny (Polish), biyiktiktesh shamal (Kyrgyz), shamoli boloi (Tajik), kutariluvchi shamol (Uzbek) — wind (Azerbaijani), shamoli boloi (Tajik), kutariluvchi shamol (Uzbek), chain yukharilaryndan esen kyulek (Azerbaijani) — a wind from the upper reaches of rivers and valleys. It has different directions depending on valley orientation. In the Trans-Volga region it is a warm south-westerly wind, sometimes dry, and a sign of approaching bad weather; on the Volga it is north-westerly; in the Baikal region it is easterly or south-easterly, a sign of the onset of bad weather; on the Middle Dnipro it is north-westerly;
on the Lower Dnipro it is north-easterly; on Lake Teletskoye it is a southerly foehn, flowing down the lower reaches of the Chulyshman River; with this wind even in March the temperature can rise to 20 °C, which makes field cultivation possible on the southern shore of Lake Teletskoye. On Lake Baikal it is the barguzin, northerly or north-easterly longitudinal winds; in southern Baikal it is an easterly wind; in Komsomolsk-on-Amur, a southerly wind (compare Lamus); on eastern Kamchatka, a westerly wind with clear weather.
SPRING SQUALL — a short-lived gust of wind in spring, widespread in the USSR. Compare Vesniak.
VITROBOI — a strong autumn wind, usually north-westerly, northerly or north-easterly. It strips leaves from trees.
WINDS IN BALAKLAVA (Crimea) — trimuntan (N), bora (NE), greba-levanti (ENE), levanti (E), land wind (SE), shiroko and ostria (S), sea wind (S), ponenti (W), maistra (NW). The names were brought in ancient times by Greek fishermen. The prevailing winds here are ostria and trimuntan, which blow meridionally along the narrow mountain passage. Compare Balaklava Storm.
WINDS ON THE DANUBE — opivnochi, pyvnych, pulnoch, severiak and severats (N); yuzhak (S, SE); abaza (E, NE); karasl (SW).
WINDS IN THE KUBAN REGION — trimuntana (N), grego (NE), levant (E), kubanets (SE), garbi (S), nizovka and poludenka (SW), ponent (W), maistra (NW), bunatsia (complete calm).
VYTROVYI (Ukr.) — a strong wind in Ukraine.
VORTEX STORMS — a collective name for vortex systems of strong wind, distinguished from linear zones of strong wind, jets and drainage flows. The diameters of vortex storms range from a few metres (dust whirls, whirls), tens or hundreds of metres (waterspouts, tornadoes) to tens of kilometres (linear squalls).
WHIRLS, whirls, whirlwind (English whirls, whirlwind) — strong vortices of small diameter, from a few metres to about one hundred metres, outside which, with increasing distance from their axis, wind speed decreases from strong or hurricane force to calm. They arise under clear skies through the influence of relief and uneven heating of the underlying surface, for example during drought or a severe fire, and sometimes beneath a powerful descending wind flow reaching the ground, as if burrowing into it, as observed, for example, around the equinoxes in Antarctica on Adélie Land. Whirls develop from the bottom upward, unlike tornadoes, which arise beneath parent clouds, and move in the direction of the prevailing near-surface wind that carries them. They usually dissipate quickly, but can sometimes be traced for several kilometres. Most often they have an irregular column-like shape and are hollow inside. They are characteristic of steppe and desert regions, mountains, foothills and strongly dissected non-forested terrain.
VOSTOCHOK (Ukr.) — a weak easterly wind on the Dniester.
WATER SET-DOWN, set-down, vodogon, povod, padun (Pomor) — an offshore wind in the north of the USSR that lowers the water level at a river mouth, and the water-level fall itself, as opposed to set-up, a rise in water. On the Northern Dvina this is the Russian wind; on the Lower Dnipro, the upstream north-easterly wind; at the mouth of the Volga, a north-westerly wind.
Wind Names — Letter G
GALICIAN RUFFS — a south-easterly wind on Lake Onega. It raises large waves and produces whitecaps on wave crests.!!!!!
MOUNTAIN–VALLEY WINDS — winds of local air circulation between a mountain ridge and a valley with a diurnal period: during the day, valley winds, directed from valleys toward the mountains; at night, mountain winds, that is, drainage of cold air from higher ground into the valley. A distinction is made between mountain winds proper, at night, and valley winds, during the day, which occupy the entire valley floor, and slope winds that blow upslope over heated slopes during the day, in a relatively thin layer, and downslope at night.
Mountain–valley winds result from the combined action of radiative, circulation, orographic and landscape factors of weather and climate. This circulation is well developed in the warm season during anticyclonic, lightly clouded weather. In the diurnal cycle, near-surface wind strengthens during the day on valley floors and slopes and weakens toward night, after which the mountain wind begins and strengthens until dawn. In the free atmosphere above the wind-reversal level, maximum wind speed occurs at night and the minimum during the day, the opposite of what is observed near the surface. The diurnal variation in the height of the valley wind is such that it usually begins in the morning at once through a considerable thickness of the atmosphere; the height of this layer is greatest during the day and decreases toward evening.
A feature of the valley wind is that its speed decreases with height, usually up to the level of the surrounding peaks, above which the gradient wind prevails. The night-time mountain wind may begin abruptly, like a collapse of air that has cooled in the highlands.
Diagram of the development of mountain–valley winds (1) and slope winds (2)
At low latitudes, mountain–valley winds are better developed and occur more often than at high latitudes. Relief determines their extent and affects their stability and duration.
Phases in the development of mountain–valley winds are distinguished, that is, periods of change in wind speed and direction: for the mountain wind — initiation, or the beginning of gravitational air drainage; full development; accumulation of a lens of cold air and its filling of the foothills; a relict inert mass of cold air; morning gravitational drainage; and decay of the mountain wind; for the valley wind — initiation, or upslope air pull; formation of mountain-convective cloudiness; full development; and decay (M. F. Helmholtz, O. A. Drozdov). In the morning and evening, pauses in mountain–valley winds are observed, periods of calm while the wind direction changes.
Mountain winds have various local names, for example mtis kari (Georgian), dag kyuleyi (Azerbaijani), shamoli kuhi (Tajik), too shamaly (Uzbek), Bergwind and Oberwind (German), mountain wind (English). Valley winds are respectively called kheobis kari, dere kyuleyi, shamoli vodi, oroon shamaly, vodiy shamoli, Talmesher Wind and Unterwind, valley wind.
MOUNTAIN BREEZE — see Breeze.
MOUNTAIN WIND — see Mountain–Valley Winds.
HORYSHNII WIND, horyshniachok — a weak northerly upstream wind in the Dniester region, as well as an upstream mountain wind in Crimea and the Carpathians.
GREGAL, gregala, grekal (Spanish gregal, French grécale); grego, gregos, grek (Latin graecus — blowing from Greece) — a continental north-easterly wind, a north-east wind, in the Mediterranean basin. It occurs with an incursion of dry continental air, cold in winter and warm in summer. In spring and autumn it is accompanied by unpleasant frosty weather with drizzle, snow or rain. It is often strong.
Some local differences are noted. Thus, in southern France in the Lower Rhône basin it is called gréal, gargal and grec; at Marvejols, Lozère department, it is a south-easterly wind; in Marseille it is a breeze (see Plauvinau).In Malta it is called the Balkan wind; in the Tyrrhenian Sea, gregolia and greco; in the eastern Mediterranean and the Azov–Black Sea basin, grego, gregos and greco. On the Sea of Azov, sailors call the easterly wind gregor. In these sea basins, gregolevantes and gregolevant are distinguished as east-north-easterly winds, in Greece and Italy and at Yalta and Balaklava, as well as gregotramontana, a north-north-easterly wind in Greece, Sulina and Yalta.
GREGO, greco — see Gregal.
Wind Names — Letters K, L, M
KIDAIE KAMINNIA (Ukr., “throws stones”) — a strong wind in the Dniester region.
KYMBUR (Ukr.) — an easterly wind in the Lower Dniester region.
KYMLACH (Ukr.) — a strong wind in the Dniester River basin.
KLIMAT, tramontan, tramontana — a cold northerly wind from the mountains at Yalta, a katabatic flow, a weak bora. It does not extend far out to sea.
LIGHT WIND — a wind with a speed of 1.6–3.3 m/s, force 2 on the Beaufort scale, causing tree leaves to rustle.
ICE STORM — a strong wind accompanied by rain falling from comparatively warm air onto a frozen ground surface. An ice crust, glaze ice, forms on objects at the surface. A strengthening of the wind under such conditions is often accompanied by damage and broken trees.
FOREST WIND — local air circulation that arises on a clear night between a forest and an open area, at the forest edge. Air cooled by contact with cold leaves and tree branches descends and flows into the open area, replacing air removed by the return circulation above the trees. Wind direction is determined by the direction of the horizontal temperature gradient: the near-surface wind is directed from the more strongly cooled area toward the warmer one. The forest wind does not extend far from the forest edge or deep into the forest. Compare Breeze.
LODOZ (Turkish lodoz, from Greek notos) — a warm southerly or south-westerly white wind with fine weather on the western shores of the Black Sea. It is observed in summer and autumn. Batı lodoz, a south-westerly wind; kıble lodoz, a south-south-westerly wind; and lodoz poyraz, a south-easterly wind, are distinguished.
LOCAL WINDS, local air circulation — air currents of small horizontal extent, from hundreds of metres to tens of kilometres, arising from local disturbance of a larger air flow under the influence of orography and landscape features. These include breezes, mountain and valley winds, foehn, bora, glacier and drainage winds.Sometimes local storms that arise within the general circulation system under the influence of the characteristics of a large territory or local manifestations of convection, such as storms in African deserts, are also included.
Local winds have the vertical profile of a mesojet and are an important factor in local climate.
Local winds are classified according to genetic, morphological, spatial-kinematic and temporal characteristics (see Classification of Winds).
LOCAL STORMS — see Local Winds.
URBAN WINDS — winds arising from the deformation of large air flows in areas of urban development. Wind in a city blows mainly along streets, and its direction may not coincide with the general air flow above the city. At street intersections and in narrowed streets between buildings, jets and vortices arise and are especially noticeable during blizzards. Wind jets across streets form a kind of closed circulation, with air rising on one side of the street and descending on the other. Wind strengthens in narrow passages. Air rises along walls heated by the Sun and descends along shaded walls. At night, during calm conditions,air drains along both sides of streets and rises along their middle. Air above the city is warmer, causing winds to develop from the outskirts toward the centre, above which ascending air currents form. The greatest differences between wind speeds in a city and on its outskirts are observed in spring.
URBAN BREEZE — a wind that blows from the outskirts toward the city during the day and in the opposite direction, from the centre toward the outskirts, at night. It develops in lightly clouded weather during the warm season. See Urban Winds.
Strong blizzards occur in the zone of a warm atmospheric front and south or south-east of intense cyclones, in the forward part of deep baric troughs. During a blizzard, wind-driven evaporation of snow (ablation) is observed.
SEA BREEZE — see Breeze.
SEA WIND, moriak, moriana, morianyk, maren, marinada, Auflandiger Wind (German), altan (Latin altanus)— a daytime breeze blowing toward the land. It usually begins in the morning, reaches maximum speed after midday, and subsides around sunset, being replaced by a night-time land breeze, blowing toward the body of water. It sometimes penetrates far inland. In Saudi Arabia, for example, it penetrates 200–225 km inland at speeds of up to 7 m/s, occupying an atmospheric layer more than 1,200 m deep. The direction of the sea wind depends on relief and the orientation of the shoreline. Compare Otan.
MORIAK — see Black Sea Moriak. Black Sea Breeze.
Wind Names — Letters P, U, Kh
TRADE WINDS — persistent easterly winds, tropical easterly transport, with a component directed toward the equator. They arise on the equatorial periphery of subtropical dynamic anticyclones. They develop in the trade-wind zone between 6° S and 28° N in the Northern Hemisphere winter and between 30° N and 30° S in summer. The width and position of the trade-wind zone change from season to season and also differ in different parts of the ocean. The average speed of the trade winds is 5–6 m/s. However, they strengthen near capes and islands. For example, the north-easterly trade wind near Socotra Island in the Arabian Sea, at the entrance to the Gulf of Aden, is notable not only for its frequency but also for its strength; as a result, for half the year small vessels cannot approach the island closer than 40 miles.
In winter, the easterly trade-wind flow occupies the entire troposphere up to a height of 16 km; in summer it does not extend above 10 km. Above the trade winds, a westerly antitrade wind prevails.
The atmospheric-circulation system in the trade-wind latitudes, consisting of the trade winds and antitrade winds, forms the trade-wind circulation ring, or wheel.
Trade winds are usually accompanied by lightly clouded, dry weather because cloud development is inhibited by the trade-wind inversion or a restraining layer. Trade-wind cumulus clouds are weakly developed vertically and often have a stratocumulus character. Sometimes powerful cumulus clouds break through the inversion layer. Trade-wind rains are observed on the windward, eastern parts of islands and coasts. They are most intense in winter, during periods of strong trade-wind development.
The trade-wind inversion lies at heights of 1–2 km and separates the lower main trade-wind current from the upper, warmer and drier air. In the intertropical convergence zone, the inversion is absent, creating conditions for the development of cumulonimbus clouds.
The trade-wind climate, the climate of regions under the influence of the trade winds, is characterised by persistent winds — for example, in the Hawaiian Islands, trade winds prevail on 90% of summer days and 50% of winter days — and dryness. On plains this is the climate of trade-wind deserts, such as the Sahara and Kalahari, formed under the influence of drying winds such as the harmattan.
In the zone where the trade winds of the Northern and Southern Hemispheres meet, or where a trade wind meets a monsoon, a trade-wind, or tropical, atmospheric front forms. It lies in a baric trough between the subtropical anticyclones of both hemispheres. In the Mediterranean, the trade-wind front separates the north-easterly trade wind from the south-westerly monsoon, which transitions into the antitrade wind. In the zone of low fronts, the south-westerly flow produces hot, dry weather in summer and cold, cloudy weather with light rain in winter. In spring, cyclones form on such fronts over the plains of North Africa (see Intertropical Convergence Zone).
Over the ocean, trade winds cause drifting equatorial trade-wind currents, the North and South Equatorial Currents in the Atlantic and Pacific oceans, with speeds of 15–20 cm/s that increase toward the equator. The warm Gulf Stream current is affected, as a result of which more warm Atlantic water passes near Iceland and water levels in the North and Baltic seas change, usually lowest in spring and highest in autumn.
HURRICANE (from a word meaning an evil spirit in an indigenous language, Araucanian hurrican). — 1. A wind of destructive force and considerable duration, unlike a squall, force 12 on the Beaufort scale, 32.7 m/s or more. Sometimes even a force-9 wind is called a hurricane because of its destructive effects. 2. Tropical cyclones, including Antillean, West Indian hurricanes and the typhoons of the Far East. 3. In the southern Sahara, summer squalls with catastrophic downpours and thunderstorms are incorrectly called African hurricanes. They arise in the zone where the beginning or ending rains of the south-westerly monsoon meet the north-easterly trade wind. Timbuktu experiences 8–10 such hurricanes per year. The south-westerly monsoon season begins and ends with a period of hurricanes; squally wind gusts begin and end these short, violent atmospheric disturbances. The hurricanes move from east to west with the trade wind. Compare African Waves.
Among the K’iche’ peoples of Central America, Huracán is the god of thunder and storms, the one-legged god of fear, bad weather and tempests. Among the Aztecs this god is called Tezcatlipoca. In myth he is associated with the constellation Ursa Major.
HURRICANE TORNADOES — tornadoes smaller than usual that form on the periphery of the main hurricane flow as independent vortices, funnels that reach the Earth’s surface. They are usually observed in the right quadrant of the storm zone, outside the wind wall of the tropical cyclone.
Wind Names — Letters Ch, Sh, Kh
CHYSTYI HORYSHNIAK — a persistent northerly wind in the Dniester region.
SQUALL — a sharp increase in wind speed over a short period, accompanied by a change in direction. Wind speed during a squall often exceeds 20–30 m/s. A squall usually lasts several minutes. Repeated gusts are sometimes observed. During a squall there is a jump in atmospheric pressure, producing a characteristic spike on a barogram, a change in relative humidity and a rapid drop in temperature. A squall is often accompanied by heavy rain and a thunderstorm, a shower.
Air-mass and frontal squalls are distinguished. Air-mass squalls are associated with powerful convective clouds — cumulonimbus clouds arising in hot summer weather over land or in cold, unstably stratified air masses over a warm underlying surface. Frontal squalls are associated mainly with cold atmospheric fronts and prefrontal cumulonimbus clouds. In both cases, vortex motion of air with a horizontal axis of rotation is observed within and beneath the clouds.
In the USSR, only 10% of squalls are air-mass phenomena; the remainder are associated mainly with fronts. Squalls should be distinguished from wind gusts lasting 10–30 seconds. Orographic squalls, arising from the influence of orography on the main atmospheric air flows, are also distinguished. These include, for example, bora and foehn.
Depending on the accompanying weather, a white squall is distinguished, arising for dynamic reasons when an air flow is deformed by features of the underlying surface or when different air flows interact; a black squall, accompanied by overcast weather; a dry squall, in which precipitation does not reach the Earth’s surface because of dry air; a thunderstorm squall, accompanied by a sharp blast of gusty wind before and during a thunderstorm; a rain squall, accompanied by a heavy downpour; a dust squall, and so on. In summer, squalls associated with powerful convection may be accompanied by thunderstorms even in comparatively dry air. In such cases precipitation does not reach the Earth’s surface.
At southern latitudes and on uplands, squalls occur more often than in the north and on plains. For example, an area of increased squall frequency is observed in the Southern Urals, the Volga Upland, Central Russian Upland, Volhynian–Podolian Upland, the Crimean yaylas and other places with complex orography. Squalls occur most often in mountainous areas — the Caucasus, Tian Shan and Yablonovy Range — where up to 80 squalls occur annually, almost everywhere.
SQUALLY WIND — a wind whose gusts exceed the mean wind speed by 10 m/s or more. Each gust lasts a little more than 20 seconds.
The frequency of wind gusts is in some cases its principal characteristic, for example during a strong bora or foehn.
CALM — see Windlessness.
STORM, tempest — a prolonged, very strong wind accompanied by destruction on land and heavy seas. Wind speed exceeds 24 m/s, or force 10 on the Beaufort scale. Because of destructive effects, a force 8–9 wind, 17–24 m/s, is sometimes also called a storm. A strong storm, severe storm, violent storm, force 11, and hurricane, force 12, are distinguished.
STORMS OF THE SEA OF AZOV — mainly north-easterly dangerous winds of monsoon type that cover large areas of the south-east of the European territory of the USSR and are accompanied by severe frosts. They occur 20–30 times a year and reach high speeds. On the Sea of Azov they are dangerous to vessels. These winds drive waves from the head of Taganrog Bay over 300–400 km, causing heavy surf. The waves break ice, pile up hummocks along the Arabat Spit, roll over it and form cones of sand and shell deposition on the ice of Syvash (see Greus). In spring, southerly and westerly winds become more frequent. In summer there are no more than one or two storm days per month. These are mainly squalls on cold atmospheric fronts. Waterspouts are observed occasionally.
One of the principal features of the sea’s wind regime is the considerable change in coastal water level during set-down and set-up winds. Wind waves affect the entire water column down to the bottom because shallow depths predominate. When the wind weakens, wave action quickly subsides. Wind waves have a short wavelength and considerable steepness. Choppy seas are often observed because waves are reflected from the shores.
STORMS OF THE BLACK SEA — mainly north-easterly dangerous winds representing the winter continental monsoon. They are observed most often in December and March. The average duration of a storm is 10–30 hours, and in some cases 100 hours or more. They are accompanied by severe cooling, snowfall and sea smoke. In spring, north-westerly storms occur, accompanied by cloudy, unsettled weather. Southerly storms are less frequent than others. Waterspouts sometimes occur on hot days. In autumn and winter, cyclones break into the sea and generate violent, prolonged storms from the west, south and sometimes south-east. Storms are observed on the Black Sea on 50–60 days per year.
A number of bays and gulfs have their own storm-regime characteristics. These include, for example, the autumn–winter bora at Novorossiysk, Gelendzhik and Tuapse. In Batumi Bay, a seiche-like surge is observed with westerly winds, while south-westerly winds produce swell. On the southern coast of the sea, the most dangerous areas are Mapavri and Cape Kerempe. If the mountains become covered in cloud, rain with westerly winds will begin in the coming days. In Rize Limanı Bay, between Capes Askoros and Fener, a north-westerly wind drives large waves, while the south-westerly wind that replaces it causes rough seas. Storm frequency here is highest in winter. In Trabzon Bay, between Capes Hupsi and Güzelhisar, storms occur in all seasons. North-easterly and north-westerly winds are especially dangerous, generating severe rough seas. An easterly wind produces swell called kalam. In Samsun Bay, north-easterly winds in winter can reach storm force and cause heavy seas. They are accompanied by rain, sometimes hail, and continue for several days. In Sinop Bay, storms are usually observed in winter with south-easterly, north-westerly or westerly winds.
In the Bosporus Strait, north-easterly winds from the Black Sea usually blow during the day and subside by night. In winter, the north-easterly wind blows persistently here (see Dardanelles Wind) under cloudless skies; when it breaks westward it brings haze and clouds with rain, often snow or even hail. Frost can reach −10 °C. North-westerly winds blow rarely but are squally and often accompanied by rain. Southerly winds are accompanied by fine weather.
Near Odesa Bay, squally storms occur mainly with north-easterly winds. In winter they bring fog. At the port of Ochakiv, strong south-westerly winds produce a surge. Strong easterly Ochakiv squalls are also observed here — sudden wind gusts that sometimes reach hurricane force. They arise on the northern periphery of a Black Sea cyclone and are associated with an atmospheric front extending latitudinally. Dust storms occur in Mykolaiv during the warm part of the year. On the southern coast of Crimea, at Alushta and Yalta, strong winds usually blow from the mountain passes (compare Maistra, Tramontana, Foehn, Bora).
BLIZZARD.
Blizzard, viia, viialytsia, khurdelytsia, khurtovyna, kura, borosho, burgalak (Kyrgyz), buroni barfi (Tajik), kar-buki (Georgian), izgirin, kor buroni (Uzbek), khaardakh sil-lie, khurta, khurtovyna (Yakut), khaardakh sil-lie, buurba (Yakut), khurta, khurtovyna (Ukr.), chovhun (Azerbaijani) — the transport of snow above the Earth’s surface by wind of sufficient strength. Sometimes snow is transported together with dust. A general blizzard (buran, khurtovyna, kura, purga, khurta), a drifting-snow blizzard (zamet, zauvazhnost, ponyzovka) and an upper blizzard (zakrutyty) are distinguished. A general blizzard with falling snow (sypukha) is the transport of snow above the Earth’s surface by sufficiently strong wind, more than about 9 m/s, while snow is falling from clouds. It is most often observed ahead of a warm atmospheric front or an occlusion front. In a drifting-snow blizzard, the wind transports snow lifted from the snow-cover surface, with the snow rising above human eye level. A drifting-snow blizzard is observed when the wind is sufficiently strong and the snow-cover surface is dry, usually in the rear of a cyclone or on the periphery of an anticyclone. Ground drifting snow (pozemok, pozem, volokusha, pisha kura, ponosukha, popovzykha, poderukha, ponos, tashchykha) is also distinguished.
A blizzard lasting more than 12 hours with wind speeds of 15 m/s or more is classified as a particularly dangerous weather phenomenon.
Relief features and the position of an area relative to snow-bearing winds determine blizzard frequency. Areas with a high frequency of blizzards include the south-west of Altai Krai, the Ob River valley, the north and north-east of the USSR, Kamchatka, Sakhalin and others.
Prokh Leonid Zusiiovych
(1921, Zhytomyr — 1983, Kyiv) — a Ukrainian synoptic engineer and meteorologist and researcher, Candidate of Geographical Sciences, educator, a noted populariser of meteorological knowledge. He served as head of an aviation meteorological station, head of a weather forecasting department, deputy director of the Far Eastern Hydrometeorological Service Administration, director of the Hydrometeorological Technical School in Vladivostok, and senior researcher at the Ukrainian Hydrometeorological Research Institute (UkrHMI) in Kyiv.
He made a significant contribution to the study of the mechanisms of dangerous natural phenomena and weather in Ukraine (storm-force winds, squalls, tornadoes, windthrows and fogs). He obtained significant results while studying mesojets and the intensification of mesojet forest-felling winds in the Carpathians. His works present original data on the mechanism of fog formation and features of its vertical and radiative structure, obtained using a self-designed thermoelectric psychrometer and a two-sided pyrgeometer.