The Somali Jet, also known as the Findlater Jet, is a cross-equatorial wind system which forms off the eastern coast of

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

. It is recognised as an important component of the

Indian Monsoon The Monsoon of South Asia is among several geographically distributed global monsoons. It affects the Indian subcontinent, where it is one of the oldest and most anticipated weather phenomena and an economically important pattern every year fro ...

and is a factor in the relatively low rainfall in

East Africa East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...

. It contributes to the existence of the

Somali Current The Somali Current is a cold ocean boundary current that runs along the coast of Somalia and Oman in the Western Indian Ocean and is analogous to the Gulf Stream in the Atlantic Ocean. This current is heavily influenced by the monsoons and is th ...

– the only major upwelling system that occurs on a western boundary of an ocean.

History

The Somali Jet was documented scientifically for the first time by Findlater in 1969 based on upper air data from the Maldives and Nairobi. In practice, the existence of the strong winds had long been known due to its effect on maritime trade. Piracy off the Somali Coast is thought to be limited by the strong winds, with most instances of piracy occurring when the Somali Jet is weak.

Structure

The Somali Jet is a wind maximum (>) in the lowest 1.5 km of the atmosphere, capped above by a maritime

temperature inversion In meteorology, an inversion (or temperature inversion) is a phenomenon in which a layer of warmer air overlies cooler air. Normally, air temperature gradually decreases as altitude increases, but this relationship is reversed in an inver ...

. It forms across a relatively narrow band of longitudes. In the northern hemisphere summer (July-September), the jet presents as a southeasterly wind in the southeastern

, before recurving anticylonically to the northeast on crossing the equator, parallel to the East African coast. At this time of year, the strongest jet winds are the southwesterlies in the

Arabian Sea The Arabian Sea () is a region of sea in the northern Indian Ocean, bounded on the west by the Arabian Peninsula, Gulf of Aden and Guardafui Channel, on the northwest by Gulf of Oman and Iran, on the north by Pakistan, on the east by India, and ...

. There is also a local maximum in the southeasterly winds off the northern tip of

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

. In response to the annual cycle in insolation, the jet reverses direction in the southern hemisphere summer (December to February).

References

{{reflist Winds Atmospheric dynamics