Levant (wind)
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The winds of the Mediterranean |
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The levant (Catalan: Llevant, Italian: Levante, Maltese: Lvant, Greek: Λεβάντες, Spanish: Levante) is an easterly wind that blows in the western Mediterranean Sea and southern France, an example of mountain-gap wind. In Roussillon it is called "llevant" and in Corsica "levante". In the western Mediterranean, particularly when the wind blows through the Strait of Gibraltar, it is called the Viento de Levante or the Levanter. It is also known as the Solano.
When blowing moderately or strongly, the levant causes heavy swells on the Mediterranean. Usually gentle and damp, the levant frequently brings clouds and rain. When it brings good weather, it is known as the "levant blanc",[1] or "levante calma" in Gibraltar.
The origin of the name is the same as that of the name Levant for the region of the eastern Mediterranean: it is the Latin word "levante", the participle of levare "to raise" – as in sol levante "rising sun". It thus referred to the eastern direction of the rising sun.
Etymology
The name of the wind pattern entered English from Middle French levante (French: rising), the sun rises in the east, the perceived origin point of the wind and rain. It is used to describe the direction east, the wind coming from the east, as well as a general term for the lands bordering the eastern Mediterranean.
Description
The wind rises in the central Mediterranean or around the
The Strait of Gibraltar
The Strait of Gibraltar, located at the western entrance to the Mediterranean Sea, is frequently associated with strong gap winds that can produce dangerous seas, especially when they blow against tide, current or swell through the Strait, which is a narrow sea-level passage about 15 km (9.3 mi) wide and 55 km (34 mi) long that is surrounded by terrain reaching several thousand feet.
The most pronounced gap wind through the Strait, the Levanter, can produce winds of 20 to 40 kn (40 to 70 km/h) in and to the west of the gap when there is higher pressure to the east, over the Mediterranean, with lower pressure to the west of
The Gibraltar levanter cloud
Sometimes the levanter forms a characteristic cloud named "banner-cloud" over the Rock of Gibraltar. However, this is not always the case and a particular set of conditions is required for its formation.
Near the surface, the levanter is moist, but is unsaturated. As the moist air, which must be capped to be stable and so unable to rise by convection, is forced to rise over the Rock, the moisture condenses to form a cloud that streams away west from its top. If wind speeds are too low and stability high in the near-surface layer, the cloud does not form and condensation is also sensitive to small changes in moisture content, such that when the wind across the Rock veers into the southeast, the flow becomes too dry for the cloud to form, bringing drier air from North Africa. When the wind speed is too low, the air is blocked and unable to rise to form the cloud. At high wind speeds, the turbulent mixing to the lee of the Rock distributes the moisture through a comparatively deep layer and the cloud is, at best, very broken. Often it dissolves immediately west of the Rock in these turbulent windy conditions.
In suitable conditions, the characteristic "pennant" cloud forms downwind. It usually extends about 5 km (3 mi) west from the top of the Rock in a turbulent plume. (Similar clouds may sometimes be seen elsewhere – notably the pennant cloud that forms on the Matterhorn in Switzerland.) This cloud hangs over the centre of the city of Gibraltar, while there is usually sunny weather in to the north and south from the southern outskirts of the city.
On the western side of the Rock, the winds near sea level are often from the west or southwest, as the air forms large overturning rolls, more than 350 m (1,100 ft) deep in the lee protection of the mountain, but strong winds tend to alter this flow regime.
The pennant cloud is not seen in westerly winds, although many of the same processes occur - it is just that the air is usually drier and may be warmer, as well as being less stable – so that convection from the surface is deeper and not capped near the mountaintop level. (Low cloud can sometimes be seen on the Rock, early in the morning in westerly winds, but this disappears as temperatures rise. It is also likely that the very steep eastern slope of the Rock tends to make the downwind flow too turbulent for cloud formation.)
Around dawn, the flow is relatively smooth through the cloud, but later in the morning, as it becomes warmer, some convective overturning develops within the plume as temperatures rise.
Formation of the cloud is classically very near the top of the ridge-line of the Rock at nearly 400 m (1,300 ft) altitude, but the base is usually a little lower in the turbulent flow to the west. The top of the cloud is rarely much more than 450 m (1,500 ft) above
Strong winds across the Rock
When winds are very strong across the crest of the Rock, usually in excess of 15 m/s (34 mph), the cloud becomes detached from the crest of the Rock forming west of a line parallel to the ridge up to about 100 m (300 ft) from it. At the same time, curved arcs of cloud may be seen within or below the pennant cloud, indicating the formation of a
In popular culture
- This wind is a Gibraltarian Flamenco Metal band Breed 77, who titled a track from their 2006 In My Blood (En Mi Sangre)album "Viento De Levante".
- In his novel brought the Moors to Spain.
- The Levante is mentioned in the historical fiction novel The Hundred Days by Patrick O'Brian.
- Clé: Levanter is the name of the mini-album by a Korean band Stray Kids, released on December 9, 2019. The title track of the album is also titled Levanter.
- Levante is a model of the Italian car manufacturer Maserati.
References
- ^ Meteo-France website (in French) on "Vents regionaux and vents locaux"
- Bendall, A. A., 1982: Low-level flow through the Strait of Gibraltar. Meteor. Mag., 111, 149-153
- Dorman, C. E., R. C. Beardsley, and R. Limeburner, 1995: Winds in the Strait of Gibraltar. Quart. J. Royal Met. Soc., 121, 1903–1921
- Galvin, J. F. P., A. I. Black, and D. A. Priestley, 2011: "Mesoscale weather features over the Mediterranean: Part 1". Weather, 66, 72-78
- Scorer, R.S., 1952: Mountain-gap winds; a study of the surface wind in Gibraltar. Quart. J. Royal Met. Soc., 78, 53-59
- Vialar, Jean, 1948: Les vents régionaux et locaux, reissued by Météo-France in 2003
External links
- Meteo-France French-language on meteorology