Wind is the quasi-horizontal movement of This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. If an article link referred you here, you might want to go back and fix it to point directly to the intended page. Air is a name for the mixture... air (as opposed to an air The word current usually implies a flow or movement. There are several uses of the word in English: An electrical current A flow of water or other fluid (including air; see wind); particularly, an ocean current. An adjective meaning recent or up-to-date, as in current affairs or his... current) caused by a horizontal Pressure (symbol: p or P) is the measure of the force that acts on a unit area. where: p is the pressure F is the force A is the area Often F is taken to be the of the magnitude of the mean vector force normal to the surface of... pressure In vector calculus, the gradient of a scalar field is a vector field which points in the direction of the greatest rate of change of the scalar field, and whose magnitude is the greatest rate of change. In the following two images, the scalar field is in black and white... gradient force. It occurs at all scales, from local breezes generated by heating of land surfaces and lasting tens of minutes to The adjective global and adverb globally imply that the verb or noun to which they are applied applies to the entire Earth and all of its species and regions. It is sometimes used as a synonym for the much narrower international/internationally but this is incorrect: Only two nations need... global winds resulting from Solar heating is a style of building construction which uses the energy of sunshine to heat a structure. Active solar heating uses pumps which move air or a liquid from the solar collector sometimes into the building, sometimes into a storage area. Passive solar heating relies on the design and... solar heating of the Earth, also known as the Earth or Terra, is the third planet outward from the Sun. It is the largest of the solar systems terrestrial planets, and the only planetary body that modern science confirms as harboring life. The planet formed around 4.5 billion (4.5×109) years... Earth. The two major influences on the atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet ( In physics, the Coriolis effect is a manifestation of inertia first described in full by Gaspard-Gustave Coriolis, a French scientist, in 1835. Formula The formula for the coriolis force is as follows. In this formula the arrow above the symbol indicates vector quantities, is the coriolis force, m is... Coriolis effect).

Given a difference in Schematic drawing of a simple mercury barometer with vertical mercury column and reservoir at base A barometer is an instrument used to measure atmospheric pressure. A standard mercury barometer has a glass column of about 30 inches (about 76 cm) in height, closed at one end, with an open mercury... barometric Pressure (symbol: p or P) is the measure of the force that acts on a unit area. where: p is the pressure F is the force A is the area Often F is taken to be the of the magnitude of the mean vector force normal to the surface of... pressure between two air masses, a wind will arise between the two which tends to flow from the area of A high, or a high pressure area, is a region where the atmospheric pressure is greatest with relation to the surrounding area. Highs are frequently associated with light winds and subsidence. Subsidence will generally evaporate most cloud droplets after less than 500 meters, due to adiabatic heating. Thus, high pressure... high pressure to the area of A low, or a low pressure area, is a region of rising atmospheric air. Active weather on Earth is defined by the presence of lows, which generally produce cloud, strong winds, and precipitation. Low pressure areas may be formed in one of three ways. On Earth, they are most commonly... low pressure until the two air masses are at the same pressure, although these flows will be modified by the In physics, the Coriolis effect is a manifestation of inertia first described in full by Gaspard-Gustave Coriolis, a French scientist, in 1835. Formula The formula for the coriolis force is as follows. In this formula the arrow above the symbol indicates vector quantities, is the coriolis force, m is... Coriolis effect in the extratropics.

Winds can be classified either by their scale, the kinds of forces which cause them (according to the atmospheric In advanced physics, equations of motion usually refer to the Euler-Lagrange equations, differential equations derived from the Lagrangian. The following article is about elementary physics only. Linear equations of motion In kinematics, four equations of motion (or kinematic equations) apply to bodies moving linearly (in that is, one dimension... equations of motion), or the geographic regions in which they exist. There are global winds, such as the wind belts which exist between the Atmospheric circulation is the large-scale movement of air, and the means (together with the ocean circulation, which is smaller [1]) by which heat is distributed on the surface of the Earth. The large-scale structure of the atmospheric circulation varies from year to year but the basic structure remains... atmospheric circulation cells. There are upper-level winds, such as the Jet streams are fast flowing, confined air currents found in the atmosphere at around 12 km above the surface of the Earth, just under the tropopause. They form at the boundaries of adjacent air masses with significant differences in temperature, such as of the polar region and the warmer air... jet streams. There are synoptic-scale winds that result from pressure differences in surface air masses in the middle latitudes, and there are winds that come about as a consequence of Physical map of the Earth (Medium) (Large 2 MB) Geography is the scientific study of the locational and spatial variation in both physical and human phenomena on Earth. The word derives from the Greek words γη or γεια (Earth) and γραφει... geographic features such as the A sea breeze or seabreeze is a thermally-forced mesoscale (i.e. local-scale) meteorological circulation that develops across boundaries of water and land surface types, especially coastal regions. Due to solar heating and the thermal properties of land and water, the land surface heats up faster than the ocean... sea breeze. Spatial scale provides a shorthand form for discussing relative lengths, areas, distances and sizes. A microclimate, for instance, is one which might occur in a mountain valley or near a lakeshore, whereas a megatrend is one which involves the whole planet. It is important to realize that these divisions are... Mesoscale winds are those which act on a local scale, such as gust fronts. At the smallest scale are the winds which blow on a scale of only tens to hundreds of metres and are essentially unpredictable, such as dust devils and microbursts.

Winds can also shape landforms, via a variety of Eolian (or aeolian) processes pertain to the activity of the winds. Winds may erode, transport, and deposit materials, and are effective agents in regions with sparse vegetation and a large supply of unconsolidated sediments. Although water is much more powerful than wind, eolian processes are important in arid environments such... eolian processes.

Winds by spatial scale

Prevailing winds — the general circulation of the atmosphere

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The worlds major wind systems This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. This applies worldwide. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this...

Global wind systems

Prevailing winds are winds which come about as a consequence of Atmospheric circulation is the large-scale movement of air, and the means (together with the ocean circulation, which is smaller [1]) by which heat is distributed on the surface of the Earth. The large-scale structure of the atmospheric circulation varies from year to year but the basic structure remains... global circulation patterns. These include the Trade Winds, the Westerlies, the Polar Easterlies, and the jet streams.

Because of differential heating and the fact that warm air rises and cool air falls, there arise circulations that (on a non-rotating planet) would lead to an equator-to-pole flow in the upper atmosphere and an pole-to-equator flow at lower levels. Because of the Earth's rotation, this simple situation is vastly modified in the real atmosphere. In almost all circumstances the horizontal component of the wind is much larger than the vertical — the exception being violent Convection is the transfer of heat by the motion of or within a fluid. It may arise from temperature differences either within the fluid or between the fluid and its boundary, or from the application of an external motive force. It is one of the three primary mechanisms of heat... convection.

The Trade Winds are the most familiar consistent and reliable winds on the planet, exceeded in constancy only by the A katabatic wind is a wind blowing down a gradient caused by buoyancy forces - ie the air is cool. Over the major Ice sheets of Antarctica and Greenland katabatic winds blow with great constancy particularly during the polar night, when heat loss by radiation from the surface cools the overlying... katabatic winds of the major An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 square kilometers (12 million acres). The only current ice sheets are Antarctic and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of... ice sheets of World map showing location of Antarctica A satellite composite image of Antarctica For the Kim Stanley Robinson novel see Antarctica (novel) Antarctica (from Greek ἀνταρκτικός, opposite the arctic) is a continent surrounding the Earths South Pole. It is the... Antarctica and This article is about Greenland, the island dependency of Denmark. For information about the United States town of Greenland, see Greenland, New Hampshire. Greenland (Greenlandic: Kalaallit Nunaat, The Land of the Greenlanders (Kalaallit); Danish: Grønland) is a self-governed Danish territory and an Arctic island nation located in North... Greenland. It was these winds that early mariners relied upon to propel their ships from Europe to North and South America. Their name derives from the Old English 'trade', meaning "path" or "track," and thus the phrase "the wind blows trade," that is to say, on track.

The Trades form under the The major driving force of atmospheric circulation in the tropical regions is solar heating. Because of the Earth’s 23.5 degree axial tilt, the sun is never more than a few tens of degrees from directly overhead at noon in the tropics; as a consequence, incident solar radiation... Hadley circulation cell, and are part of the return flow for this cell. The Hadley carries air aloft at the equator and transports it poleward north and south. At about 30°N/S latitude, the air cools and descends. It then begins its journey back to the equator, but with a noticeably westward shift as a result of the action of the In physics, the Coriolis effect is an inertial force first described by Gaspard-Gustave Coriolis, a French scientist, in 1835. When the equations of motion are formulated in a rotating coordinate system a term arises which looks like a force, called the Coriolis force. See also centrifugal force. In changing... Coriolis force.

Along the east coast of North America, friction twists the flow of the Trades even further clockwise. The result is that the Trades feed into the Westerlies, and thus provide a continuous zone of wind for ships travelling between Europe and the Americas.

The Westerlies, which can be found at the mid-latitudes beneath the Atmospheric circulation is the large-scale movement of air, and the means (together with the ocean circulation, which is smaller [1]) by which heat is distributed on the surface of the Earth. The large-scale structure of the atmospheric circulation varies from year to year but the basic structure remains... Ferrel circulation cell, likewise arise from the tendency of winds to move in a curved path on a rotating planet. Together with the airflow in the Ferrel cell, poleward at ground level and tending to equatorial aloft (though not clearly defined, particularly in the winter), this predisposes the formation of eddy currents which maintain a more-or-less continuous flow of westerly air. The upper-level polar jet stream assists by providing a path of least resistance under which low pressure areas may travel.

The Polar Easterlies result from the outflow of the Polar high, a permanent body of descending cold air which makes up the poleward end of the Atmospheric circulation is the large-scale movement of air, and the means (together with the ocean circulation, which is smaller [1]) by which heat is distributed on the surface of the Earth. The large-scale structure of the atmospheric circulation varies from year to year but the basic structure remains... Polar circulation cell. These winds, though persistent, are not deep. However, they are cool and strong, and can combine with warm, moist For the album by Ocean Colour Scene, see North Atlantic Drift (album) The Gulf Stream is orange and yellow in this representation of water temperatures of the Atlantic. Source:NASA. The Gulf Stream, also known as the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that... Gulf Stream air transported northward by weather systems to produce violent A rolling thundercloud over Enschede, The Netherlands. A thunderstorm is a form of severe weather characterized by the presence of lightning and its attendant thunder. It is often accompanied by copious rainfall, or, on occasion, snowfall. Thunderstorms form when significant condensation, resulting in the production of a wide range of... thunderstorms and For other uses of Tornado, see Tornado (disambiguation). A land tornado. A waterspout near Florida. A tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud. The word tornado comes from the Spanish or Portuguese verb tornar, meaning to turn. The phenomenon appears in storms all around the... tornadoes as far as 60°N on the North American continent.

Records of tornadoes in northerly latitudes are spotty and incomplete because of the vast amount of uninhabited terrain and lack of monitoring, and it is certain that tornadoes have gone unseen and unreported. The deadly Edmonton tornado of 1987, which ranked as an F4 on the The Fujita scale rates a tornados intensity by the damage it inflicts on human-built structures. It was introduced in 1971 by T. Theodore Fujita of the University of Chicago who developed the scale together with Allan Pearson, head of the Forecast Center in Kansas City, Missouri Fujita scale... Fujita scale and killed 27 people, is evidence that powerful tornadoes can occur north of the 50th parallel.

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Edmonton tornado 1987 This image is in the public domain This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. This applies worldwide. File history Legend: (cur) = this is the current file, (del) = delete this old version...

The Edmonton, Canada tornado of 1987 is evidence that powerful tornadoes can develop at high latitudes.

The jet streams are rapidly moving upper-level currents. Travelling generally eastward in the tropopause, the polar jets reside at the juncture of the Ferrel cell and the Polar cell and mark the location of the polar cold front. During winter, a second jet stream forms at about the 30th parallel, at the interface of the Hadley and Ferrel cells, as a result of the contrast in temperature between tropical air and continental polar air.

The jet streams are not continuous, and fade in and out along their paths as they speed up and slow down. Though they move generally eastward, they may range significantly north and south. The polar jet stream also marks the presence of Rossby (or planetary) waves are large-scale motions in the ocean or atmosphere whose restoring force is the variation in Coriolis effect with latitude. The waves were first identified in the atmosphere in the 1939 by Carl-Gustaf Arvid Rossby who went on to explain their motion. Terrestrial waves The... Rossby waves, long-scale (4000 - 6000 km in wavelength) harmonic waves which perpetuate around the globe.

Seasonal winds

Seasonal winds are winds that only exist during specific seasons, such as the The Republic of India is the second most populous country in the world, with a population of more than one billion, and is the seventh largest country by geographical area. India has grown significantly, both in population and in strategic importance in the last two decades. The Indian economy is... Indian A monsoon is a periodic wind, especially in the Indian Ocean and southern Asia. The word is also used to label the season in which this wind blows from the southwest in India and adjacent areas that is characterized by very heavy rainfall, and specifically the rainfall that is associated... monsoon.

Synoptic winds

Synoptic winds are winds associated with large-scale events such as warm and cold In meteorology, a weather front is a boundary between two air masses with differing characteristics (e.g., air temperature or humidity). When a weather front passes over an area, it is marked by changes in temperature, wind speed and direction, atmospheric pressure, and often a change in the precipitation pattern... fronts, and are part of what makes up everyday weather. These include the Geostrophic literally means earth-turning. The geostrophic approximation is to ignore all forces other the balance between the Coriolis force and the pressure gradient force. This is a very good approximation for the synoptic scale instantaneous flow in the mid-troposphere where friction is not important - ie away from the... geostrophic wind, the gradient wind, and the cyclostrophic wind.

As a result of the Coriolis force, winds in the northern hemisphere always flow clockwise around a A high, or a high pressure area, is a region where the atmospheric pressure is greatest with relation to the surrounding area. Highs are frequently associated with light winds and subsidence. Subsidence will generally evaporate most cloud droplets after less than 500 meters, due to adiabatic heating. Thus, high pressure... high pressure area and counterclockwise around a A low, or a low pressure area, is a region of rising atmospheric air. Active weather on Earth is defined by the presence of lows, which generally produce cloud, strong winds, and precipitation. Low pressure areas may be formed in one of three ways. On Earth, they are most commonly... low pressure area (the reverse occurs in the southern hemisphere). At the same time, winds always flow from areas of high pressure to areas of low pressure. These two forces are opposite but not equal, and the path that results when the two forces cancel each other runs parallel to the An isobar is a line of equal or constant pressure on a graph, plot, or map; an isopleth of pressure. In meteorology, the pressures shown are reduced to sea level, not the surface pressures at the map locations. Also, in nuclear physics, two nuclides with the same mass number are... isobars. Wind following this path is known as Geostrophic literally means earth-turning. The geostrophic approximation is to ignore all forces other the balance between the Coriolis force and the pressure gradient force. This is a very good approximation for the synoptic scale instantaneous flow in the mid-troposphere where friction is not important - ie away from the... geostrophic wind. Winds are said to be truly geostrophic only when other forces (e.g. This article is about the resistive force. For the Japanese rock band, see Friction (band). In physics, friction is the resistive force that occurs when two surfaces travel along each other when forced together. It causes physical deformation and heat buildup. The frictional force is a function of the force... friction) acting on the air are negligible, a situation which is often a good approximation to the large-scale flow away from the The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. This area lies approximately between 23.5° N latitude and 23.5° S... tropics.

In certain circumstances, the Coriolis force acting on moving air may be almost or entirely overwhelmed by the centripetal force. Such a wind is said to be cyclostrophic, and is characterized by rapid rotation over a relatively small area. This article is about weather phenomena. For other uses, see Hurricane (disambiguation), Typhoon (disambiguation) and Tropical storm (disambiguation). Hurricane Ivan viewed from the International Space Station, September 2004. NASA photo by Edward Fincke. In meteorology, a tropical cyclone (or tropical storm, typhoon or hurricane, depending on strength and location) is... Hurricanes, For other uses of Tornado, see Tornado (disambiguation). A land tornado. A waterspout near Florida. A tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud. The word tornado comes from the Spanish or Portuguese verb tornar, meaning to turn. The phenomenon appears in storms all around the... tornadoes, and This article is about weather phenomena. For other uses, see Hurricane (disambiguation), Typhoon (disambiguation) and Tropical storm (disambiguation). Hurricane Ivan viewed from the International Space Station, September 2004. NASA photo by Edward Fincke. In meteorology, a tropical cyclone (or tropical storm, typhoon or hurricane, depending on strength and location) is... typhoons are examples of this type of wind.

Mesoscale winds

Synoptic winds occupy the lower boundary of what is considered to be "forecastable" wind. Winds at the next lowest level of magnitude typically arise and fade over time periods too short and over geographic regions too narrow to predict with any long-range accuracy. These mesoscale winds include such phenomena as the cold outflow from A rolling thundercloud over Enschede, The Netherlands. A thunderstorm is a form of severe weather characterized by the presence of lightning and its attendant thunder. It is often accompanied by copious rainfall, or, on occasion, snowfall. Thunderstorms form when significant condensation, resulting in the production of a wide range of... thunderstorms. This wind frequently advances ahead of more intense thunderstorms and may be sufficiently energetic to generate local weather of its own. Many of the "special" winds, addressed in the last section of this article, are mesoscale winds.

Microscale winds

Microscale winds take place over very short durations of time - seconds to minutes - and spatially over only tens to hundreds of metres. The Turbulent flow around an obstacle; the flow further away is laminar Laminar and turbulent water flow over the hull of a submarine Turbulence creating a vortex on an airplane wing In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by low-momentum diffusion, high momentum convection, and... turbulence following the passage of an active front is composed of microscale winds, and it is microscale wind which produces convective events such as Dust Devil Johnsonville, South Carolina A dust devil is a rotating updraft, 1000 meters high or more and tens of meters in diameter. Dust devils are often observed in times of atmospheric turbulence, especially common in the San Luis Valley of Colorado. They are visible in the Great Basin and... dust devils. Though small in scope, microscale winds can play a major role in human affairs. It was the crash of a fully loaded Orbital Sciences Stargazer Lockheed L-1011 The Lockheed L-1011 TriStar was the third widebody passenger jet airliner to reach the marketplace, following the Boeing 747 jumbo jet and the Douglas DC-10. In the 1960s, American Airlines approached Lockheed and competitor Douglas with a need for an aircraft smaller... Lockheed L-1011 at Dallas/Fort Worth International Airport, located between the cities of Dallas and Fort Worth, is the busiest airport in Texas and third busiest airport in the world in terms of operations. In terms of passenger traffic, it is the sixth busiest airport in world. In terms of land area, it... Dallas-Fort Worth International Airport in the summer of 1985 is a common year starting on Tuesday of the Gregorian calendar. Events Environmental and weather change Asian Tiger Mosquito, an invasive species is first found in Houston, Texas May 25 - Bangladesh is hit by a tropical cyclone and storm surge which kills approximately 10,000 people. September 19 - 8... 1985, and the subsequent loss of 133 lives, that introduced the term "microburst" to many people, and that was a factor in the installation of Doppler radar uses the Doppler effect to return additional information from a radar system. The Doppler effect shifts the frequency of the radar beam due to movement of the target, allowing for the direct and highly accurate measurement of speeds. Doppler radars were originally developed for military radar systems, but... doppler radar in airports and weather installations worldwide.

Local winds that are tied to specific temperature distributions

Some local winds blow only under only certain circumstances, i.e. they require a certain temperature distribution.

Differential heating is the motive force behind land breezes and sea breezes (or, in the case of larger bodies, lake breezes), also known as on- or off-shore winds. Water is a rapid absorber/radiator of heat, whereas land not only absorbs heat more slowly but releases it over a greater period of time. The result is that, in locations where sea and land meet, heat absorbed over the day will be released more quickly by the water. Air contacting water cools. Over the land, heat is still being released into the air, which rises. This convective motion draws the cool sea air in to replace the rising air, resulting in a sea breeze. During the day, the roles are reversed. The land, cooled from a night of radiation, continues to soak up heat long after the heat capacity of the water has been reached. Warm air over the water rises, pulling cool air from inland to replace it. And so it goes.

Mountain breezes and valley breezes are due to a combination of differential heating and geometry. When the sun rises, it is the tops of the mountain peaks which receive first light, and as the day progresses, the mountain slopes take on a greater heat load than the valleys. This results in a temperature inequity between the two, and as warm air rises off the slopes, cool air moves up out of the valleys to replace it. This upslope wind is called a valley breeze. The opposite effect takes place in the afternoon, as the valley radiates heat. The peaks, long since cooled, transport air into the valley in a process that is partly gravitational and partly convective and is called a mountain breeze.

Mountain breezes are one example of what is known more generally as a A katabatic wind, from the Greek word katabatikos meaning going downhill, is a wind that blows down a topographic incline such as a hill, mountain, or glacier. A distinction is drawn between winds that are warmer than their surroundings (generally called Foehn or regionally, Chinook, Santa Ana or Diablo) and... Katabatic wind. These are winds driven by cold air flowing down a slope, and occur on the largest scale in This article is about Greenland, the island dependency of Denmark. For information about the United States town of Greenland, see Greenland, New Hampshire. Greenland (Greenlandic: Kalaallit Nunaat, The Land of the Greenlanders (Kalaallit); Danish: Grønland) is a self-governed Danish territory and an Arctic island nation located in North... Greenland and World map showing location of Antarctica A satellite composite image of Antarctica For the Kim Stanley Robinson novel see Antarctica (novel) Antarctica (from Greek ἀνταρκτικός, opposite the arctic) is a continent surrounding the Earths South Pole. It is the... Antarctica. Most often, this term refers to winds which form when air which has cooled over a high, cold plateau is set in motion and descends under the influence of gravity. Winds of this type are common in regions of For the region of the same name, see Mongolia (region) Mongolia (Khalkha Mongolian: Монгол Улс) is a landlocked nation in central Asia, bordered by Russia to the north and the Peoples Republic of China to the south. It was the center of... Mongolia and in glaciated locations.

Because katabatic refers specifically to the vertical motion of the wind, this group also includes winds which form on the lee side of mountains, and heat as a consequence of compression. Such winds may undergo a temperature increase of 20°C or more, and many of the world's "named" winds (see list below) belong to this group. Among the most well-known of these winds are the Chinook has several meanings: The Chinookan nation of Native Americans of the Pacific Northwest, which inhabited the lower Columbia River valley in what is now Washington, Oregon, and British Columbia. Chinook comprise the Clatsop, Cathlamet, Multnomah, Watlala, Clowwewalla, Clackamas, Chilluckittequa and Wasco tribes Coastal Chinook and Upper Chinook are extinct... chinook of Western Canada and the American Northwest, the Swiss A foehn wind occurs when a deep layer of prevailing wind is forced over a mountain range. As the wind moves upslope, it expands and cools, causing water vapor to precipitate out. This dehydrated air then passes over the crest and begins to move downslope. As the wind descends to... foehn, California's infamous Santa Ana winds are warm, dry winds that characteristically appear in Southern California weather during autumn and early winter. Santa Anas are a type of foehn wind, the result of air pressure buildup in the high-altitude Great Basin between the Sierra Nevada and the Rocky Mountains. This air mass... Santa Ana wind, and the Spanish This article refers to the atmospheric phenomenon. For the Olympic sailing class, see windsurfing. For the French anti-air weapon system, see Mistral missile Mistral is an atmospheric phenomenon that occurs mostly in the winter and spring in the Gulf of Lion. It creates a cold, strong northwesterly wind along... mistral.

The opposite of a katabatic wind is an anabatic wind, or an upward-moving wind. The above-described valley breeze is an anabatic wind.

A widely-used term, though one not formally recognised by meteorologists, is Orography is the average height of land, measured in geopotential meters, over a certain domain. In geoscientific models, such as general circulation models, orography defines the lower boundary (except where there is ocean, of course). Because orography is spatially averaged, for example the height of the Himalaya mountains will depend... orographic wind. This refers to air which undergoes orographic lifting. Most often, this is in the context of winds such as the chinook or the foehn, which undergo lifting by mountain ranges before descending and warming on the lee side.

Winds that are defined by an equilibrium of physical forces

These winds are used in the decomposition and analysis of wind profiles. They are useful for simplifying the atmospheric In advanced physics, equations of motion usually refer to the Euler-Lagrange equations, differential equations derived from the Lagrangian. The following article is about elementary physics only. Linear equations of motion In kinematics, four equations of motion (or kinematic equations) apply to bodies moving linearly (in that is, one dimension... equations of motion and for making qualitative arguments about the horizontal and vertical distribution of winds. Examples are:

• Geostrophic literally means earth-turning. The geostrophic approximation is to ignore all forces other the balance between the Coriolis force and the pressure gradient force. This is a very good approximation for the synoptic scale instantaneous flow in the mid-troposphere where friction is not important - ie away from the... geostrophic wind (wind that is a result of the balance between In physics, the Coriolis effect is an inertial force first described by Gaspard-Gustave Coriolis, a French scientist, in 1835. When the equations of motion are formulated in a rotating coordinate system a term arises which looks like a force, called the Coriolis force. See also centrifugal force. In changing... Coriolis force and pressure gradient force; flows parallel to An isobar is a line of equal or constant pressure on a graph, plot, or map; an isopleth of pressure. In meteorology, the pressures shown are reduced to sea level, not the surface pressures at the map locations. Also, in nuclear physics, two nuclides with the same mass number are... isobars and approximates the flow above the The Atmospheric boundary layer (ABL) is the portion of the atmosphere most affected by the suns heating of the Earths surface, and by friction. It is typically 1 to 2 kilometres above ground level; the depth is dependent on the temperature of the underlying surface. Warmer surfaces in... atmospheric boundary layer in the midlatitudes if This article is about the resistive force. For the Japanese rock band, see Friction (band). In physics, friction is the resistive force that occurs when two surfaces travel along each other when forced together. It causes physical deformation and heat buildup. The frictional force is a function of the force... frictional effects are low)
• thermal wind (not actually a wind but a wind difference between two levels; only exists in an atmosphere with horizontal temperature gradients, i.e. In fluid dynamics, the baroclinity (sometimes called baroclinicity) is a measure of the stratification in a fluid. Baroclinity is proportional to which again is proportional to the angle between surfaces of constant pressure and surfaces of constant density. Thus in a barotropic fluid (which is defined by zero baroclinity), these... baroclinicity)
• ageostropic wind (difference between actual and geostrophic wind; the wind component which is responsible for air "filling up" The CYCLONE, an early computer built in 1959 by Iowa State University, was based on the Institute for Advanced Study (IAS) architecture developed by John von Neumann. As with all computers of its era, it was a one of a kind machine that could not exchange programs with other computers... cyclones over time)
• gradient wind (like geostrophic wind but also including The expression centrifugal force is used to express that if an object is being swung around on a string the object seems to be pulling on the string. In actual fact the person holding the string is doing the pulling. When an object is at speed, then if no force... centrifugal force)

Names for specific winds in certain regions

Classical Greek and Roman wind names

In ancient Greek mythology comprises the collected legends of Greek gods and goddesses and ancient heroes and heroines, originally created and spread within an oral-poetic tradition. Our surviving sources of mythology are literary reworkings of this oral tradition, supplemented by interpretations of iconic imagery, sometimes modern ones, sometimes ancient ones, as... Greek mythology, the four winds were personified as gods. The Greeks also observed the seasonal change of the winds, as evidenced by the The frieze of the tower showing the Greek wind gods Boreas (north wind, on the left) and Skiron (northwesterly wind, on the right). The tower of the winds The Tower of the Winds, also called horologion (timepiece), is an octagonal Pentelic marble tower on the Roman agora in Athens. It... Tower of the Winds in The Acropolis in central Athens, one of the most important landmarks in world history. The Parthenon, the main monument on the site, was built in favour of goddess Athena, the patron of the city Athens ( Greek: Αθήνα Athína) is the capital of Greece, and... Athens.

Roman writers later gave them Latin was the language originally spoken in the region around Rome called Latium. It gained great importance as the formal language of the Roman Empire. All Romance languages are descended from Latin, and many words based on Latin are found in other modern languages such as English. It is said... Latin names. Note: the "north wind", for example, is the wind that blows from the north, not towards it.

Modern wind names

Many local wind systems have their own names. For example:

• Bor is a municipality in the state of S o Paulo in Brazil. Its latitude is 22.6/22 1611 S and the longitude is 50.3/50 3204 W. The population in 2003 is 818 and the area is 119.53 km The elevation is 582 m... Bora (northeasterly from eastern Europe to Italy)
• Chinook has several meanings: The Chinookan nation of Native Americans of the Pacific Northwest, which inhabited the lower Columbia River valley in what is now Washington, Oregon, and British Columbia. Chinook comprise the Clatsop, Cathlamet, Multnomah, Watlala, Clowwewalla, Clackamas, Chilluckittequa and Wasco tribes Coastal Chinook and Upper Chinook are extinct... Chinook {easterly off the Rocky Mountains)
• Etesian (Greek name) or Meltemi (Turkish name) (northerly across Greece and Turkey)
• A foehn wind occurs when a deep layer of prevailing wind is forced over a mountain range. As the wind moves upslope, it expands and cools, causing water vapor to precipitate out. This dehydrated air then passes over the crest and begins to move downslope. As the wind descends to... Foehn (off the northern side of the Alps)
• The “Gregale” can occur during times when a low moves through the area to the south of Malta and causes a North Easterly wind to affect the Island. Categories: Substubs ... Gregale (northeasterly from Greece)
• Khamsin (southeasterly from North Africa to the eastern Mediterranean)
• The Levanter is an easterly wind that blows in the Western Mediterranean. The wind rises in the central Mediterranean or around the Balearic Islands and blows westwards reaching its greatest intensity through the Straight of Gibraltar. The winds a moist carrying fog and precipitation. The winds are well known for... Levanter (easterly through Strait of Gibraltar (disambiguation). Motto: Nulli Expugnabilis Hosti ( Latin: Conquered By No Enemy) Languages English ( official), an English-influenced Spanish dialect called Llanito is also spoken Capital (Gibraltar) Coordinates 36°07′ N 5°21′ W Governor and Commander-in-Chief Sir Francis Richards Chief Minister Peter... Gibraltar)
• Libeccio (southwesterly towards Italy)
• Marin (south-easterly from Mediterranean to France)
• This article refers to the atmospheric phenomenon. For the Olympic sailing class, see windsurfing. For the French anti-air weapon system, see Mistral missile Mistral is an atmospheric phenomenon that occurs mostly in the winter and spring in the Gulf of Lion. It creates a cold, strong northwesterly wind along... Mistral (northwesterly from central France to Mediterranean)
• Nor'easter (Eastern United States)
• Santa Ana winds are warm, dry winds that characteristically appear in Southern California weather during autumn and early winter. Santa Anas are a type of foehn wind, the result of air pressure buildup in the high-altitude Great Basin between the Sierra Nevada and the Rocky Mountains. This air mass... Santa Ana winds (Southern California)
• This article is about the Mediterranean wind. Sirocco is also the name of an Australian band, and Scirocco is an automobile. Sirocco, scirocco or jugo is a strong southerly to southeasterly wind in the Mediterranean that originates from the Sahara and similar North African regions. It arises from a warm... Sirocco (southerly from North Africa to southern Europe)
• The Vendevale is a westerly wind that blows into the Mediterranean Sea around the area of the Straits of Gibraltar and Morocco. This is generally associated with travelling Depressions entering the Mediterranean from the west. Categories: Africa geography stubs | Spain geography stubs | Weather ... Vendavel (westerly through Strait of Gibraltar)

Meteorological instruments to measure wind speed and/or direction

• Anemometer installation on roof of Deconism Gallery, using three size 6, schedule 40 pipes in their original uncut 20 foot (6 m) lengths. The wire (4 conductors running inside a shield) runs along the rightmost leg of the 3 legged tripod mount thats attached to the rigging that runs... anemometer (measures wind speed, either directly, e.g. with rotating cups, or indirectly, e.g. via pressure differences or the propagation speed of ultrasound signals)
• A radiosonde is a unit for use in weather balloons that measures various atmospheric parameters and transmits them to a fixed receiver. A frequency band at 403 MHz is reserved for radiosondes. The device is tied to a helium filled balloon, which lifts the device up through the atmosphere. The... rawinsonde ( Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. For other uses of the acronym GPS, see GPS (disambiguation). The Global Positioning System, usually called GPS (the US military refers to it as NAVSTAR GPS), is a satellite navigation system used for determining one... GPS-based wind measurement is performed by the probe)
• Rawinsonde weather balloon just after launch. Notice a parachute in the center of the string and a small instrument box at the end. After release it measures many parameters. These include temperature, relative humidity, pressure, and wind speed. This information is transmitted back to surface observers. A weather balloon is... weather balloon (passive measurement, balloon position is tracked from the ground visually or via This article is about the device. For the fictional character in M*A*S*H, see Corporal Walter (Radar) OReilly. This long range radar antenna (approximately 40m (130ft) in diameter) rotates on a track to observe activities near the horizon. Radar is an acronym for radio detection and ranging... radar; wind profile is computed from drift rate and the theoretical speed of ascent)
• A weather vane, also called a wind vane, is a movable device attached to an elevated object such as a roof for showing the direction of the wind. Very often these are in the shape of cockerels and are called weather cocks. Arrows are also popular, but a multitude of... weather vane (used to determine wind direction)

See also

• The Beaufort scale is an empirical measure for the intensity of the wind based mainly on sea-state or wave conditions. Its full name is the Beaufort wind force scale. It should be noted that the wave heights given pertain to the conditions found at open sea. The scale was... Beaufort scale
• Meteorology is the scientific study of the atmosphere that focuses on weather processes and forecasting. Meteorological phenomena are observable weather events which illuminate and are explained by the science of meteorology. Those events are bound by the variables that exist in Earths atmosphere. They are temperature, pressure, water vapor... meteorology
• Climatology is the science that studies climates and investigates their phenomena and causes. The discipline also referred to as climate research. A climatologist is someone who studies climatology. The principal focus of climate science is certainly atmospheric science and meteorology, but the subject is so complex that it involves many... climatology

External links

• The Winds of Mars: Aeolian Activity and Landforms (http://www.lpi.usra.edu/publications/slidesets/winds.html), paper with slides that illustrate the wind activity on the planet Mars is the fourth planet from the Sun in the solar system, named after the Roman god of war (the counterpart of the Greek Ares), on account of its blood red color as viewed in the night sky. This feature also earned it the name of Red Planet. Mars has... Mars.
• Database of Wind Characteristics (http://www.winddata.com). Wind data for wind (turbine) design and wind resource assessment and siting.
• Wind Atlases of the World (http://www.windatlas.dk). Lists of wind atlases and wind surveys from all over the world.
• A List of Named Winds (http://ggweather.com/winds.html)
• Dust Devil Movie (http://www.animalu.com/pics/dd1.htm) A short movie showing Dust Devils in action on a dry lakebed.