Viento de Levante

From Wikipedia, the free encyclopedia

This article needs sections. Please format the article according to the guidelines laid out at Wikipedia:Manual of Style (headings).

Viento de Levante or the Levanter - an easterly wind that blows in the Western Mediterranean, an example of mountain-gap wind.

The wind rises in the central Mediterranean or around the Balearic Islands and blows westwards reaching its greatest intensity through the Strait of Gibraltar. The winds are moist carrying fog and precipitation. The winds are well known for creating a particular cloud formation above the Rock of Gibraltar. The Levanter winds can occur at any time in the year, but are most common from July to October.

The Strait of Gibraltar, located at the western entrance to the Mediterranean, is frequently associated with strong gap winds that can produce dangerous seas, especially when they blow against tide and current. As shown in the figure below, the Gibraltar represents a narrow sea-level passage about 15 km wide and 55 km long that is surrounded by terrain reaching several thousand feet.

The most pronounced gap wind though the Strait is from the east and is known as the Levanter, which can produce winds of 20-40 kt in and to the west of the gap. The typical synoptic "set-up" is shown in the the sea-level pressure analysis presented below for 1200 UTC 25 August 1981. High pressure is found over the eastern Mediterranean, with lower pressure to the west of Gibraltar. The sinking motions accompanying such anticyclonic conditions often results in the formation of an inversion a few thousand feet above the surface. Such an inversion provides a vertical stable layer or cap that contains the low-level air and results in greater topographic blocking and stronger gap flow. A large horizontal gradient exists over the Strait, and winds accelerate downgradient from high to low pressure within the gap. Under such circumstances, the winds can go from near calm in the eastern Mediterranean (known as the Alboran Basin) to gale force strength on the western side of the Strait. It is important to stress that the strongest winds are not observed mid-Strait, as might be expected if the funnel mechanism was dominant; rather, the strongest winds are over the western Strait and immediately downwind to the west. Levanters are most frequent during the warm season from May through October.

The name of the wind pattern comes from the Levante, which in Spanish means East, the perceived origin point of the winds, and it is used to describe both East and the wind coming from the East. The opposite of the Levante is the Poniente (West). Levante is originated from the verb "levantar" (to rise) and refers to the fact that the sun rises from the East. In the same way, Poniente comes from the Spanish verb "poner" (or "ponerse" in its intransitive form) which in one of its acceptions means "to put down" or "to lay down" (or "to lie down") and again it refers to the fact that Sun comes down in the West. These both terms, "Levante" and "Poniente" are commonly used in Spanish sea terminology to indicate directions, East and West, while at sea.

[edit] References

• 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

• Scorer, R.S., 1952: Mountain-gap winds; a study of the surface wind in Gibraltar. Quart. J. Royal Met. Soc., 78, 53-59