Sirocco

Not to be confused with Socorro.
This article is about the Mediterranean wind. For other uses, see Sirocco (disambiguation) and Jugo (disambiguation).
The winds of the Mediterranean

Sirocco, scirocco, /sɪˈrɒkoʊ/, jugo or, rarely, siroc (Catalan: Xaloc, Greek: Σορόκος, Spanish: Siroco, Occitan: Siròc, Eisseròc) is a Mediterranean wind that comes from the Sahara and can reach hurricane speeds in North Africa and Southern Europe.

Origin of name

A sirocco from Libya blowing dust over the Mediterranean, Malta, Italy, Croatia, Montenegro, Albania and Greece

Scirocco and Sirocco are from the Greek name, σιρόκος "sirókos"[1] (through Italian scirocco [ʃiˈrɔkko]), which in turn derives from the Arabic word šarq [ʃaːrq], East) while ghibli is its name in Libya. The name jugo, pronounced [jûɡo], used in Croatia, Montenegro, Serbia, Bosnia and Hercegovina, Macedonia, Slovenia, Slovakia and hot, dust-bearing wind is called la calima. In Albanian it is called jugu. The leveche usually carries red Sahara dust and is associated with storms and heavy rain, the wind being very strong, lasting about four days. In Portugal, it is known as siroco and xaroco. In Malta, it is known as xlokk.[2] In Levantine Arabic (Lebanon and Syria) a similar wind is referred to as شلوق shlūq.

Development

It arises from a warm, dry, tropical airmass that is pulled northward by low-pressure cells moving eastward across the Mediterranean Sea, with the wind originating in the Arabian or Sahara deserts.[3] The hotter, drier continental air mixes with the cooler, wetter air of the maritime cyclone, and the counter-clockwise circulation of the low propels the mixed air across the southern coasts of Europe.

Effects

The Sirocco causes dusty dry conditions along the northern coast of Africa, storms in the Mediterranean Sea, and cool wet weather in Europe. The Sirocco's duration may be as short as half a day or may last several days. Many people attribute health problems to the Sirocco either because of the heat and dust along the African coastal regions or because of the cool dampness in Europe. The dust within the Sirocco winds can cause abrasion in mechanical devices and penetrate buildings.

Sirocco winds with speeds of up to 100 kilometres per hour are most common during the autumn and the spring. They reach a peak in March and in November when it is very hot, with a maximum speed of about 100 km/h (55 knots).

Combined with a rising tide, Sirocco is a factor responsible for the Acqua Alta phenomenon in the Venetian Lagoon.

Similar winds

Other prominent wind systems in the region are the bora/bura/burja (northwestern) and the llebeig/lebeccio/lebić (southwestern).

Calima

The calima is a hot, oppressing dust-laden, southerly to southeasterly, sometimes easterly wind in the Canary Islands region. It is particularly prevalent in winter. Like its "big brother" the sirocco, the calima blows out of a high-pressure area over Northern Africa and the Sahara and is normally drawn northwards ahead of a passing cold front or depression north of the archipelago. Its fine yellowish-brown dust creeps through doors and windows. Outside visibility often reduces to nil.

Sometimes a rare small depression forming southwest of the Canary Islands increase wind speed and intensity of a calima event. Such storms and the rising warm and humid air can lift dust up to 5,000 m above the Atlantic, blanketing hundreds of thousands of square miles of the eastern Atlantic Ocean with a dense cloud of Saharan sand, many times reaching as far as the Caribbean.

The hot and humid calima is often associated with fog and patchy drizzle and the Canary people suffer from respiratory problems. Conditions become so bad that they force public life and transport to a standstill. On January 8, 2002, the international airport at Santa Cruz had to be closed because visibility dropped to less than 50 meters.

See also

References

  1. ↑ Glossary of Meteorology (2012-01-26). "Sirocco". American Meteorological Society. Retrieved 2014-03-31.
  2. ↑ Encyclopaedia Britannica. Scirocco/xlokk Retrieved on 2007-05-19.
  3. ↑ Golden Gate Weather Services. Names of Winds. Retrieved on 2006-12-28.

External links

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