See also: Trade wind (homonymy)

The trade wind is a blowing Vent of is in west systematically subtropical high pressures towards the low equatorial pressures . In the northern Hemisphere, it blows of the North-East towards south-west, in the Southern hemisphere of south-east towards the North-West.

A trade wind is a wind of the intertropical areas (between southern 23°27 northern and 23°27), of dominant general the North-East for the hemisphere Northern and south-eastern for the blowing southern hemisphere between the sea level (0 m) up to 1500 m even 2000 Mr. C' is only starting from 6000 m of altitude that one meets the Jet-Stream S . The general circulation of the winds at low altitude (up to 2000 m) is mainly controlled by east winds in the tropical and equatorial areas, contrary to the moderate areas where it results overall in winds of west.

The trade winds are at the beginning of the dry winds; this is why the continental trade winds, which cross emerged and frequently arid grounds, differ by their nature from the oceanic trade winds, which blow lengthily above surfaces of water to high temperature and can be thus regenerated out of steam.

The continental trade winds, when they blow above desert or semi-desert areas, cannot that to maintain the aridity these areas as it is the case of the Harmattan, which in summer circumvents the thermal depression of the the Sahara, and in any season drains the accesses of the west of Africa.

The oceanic trade winds, on the contrary, collect the escaped water of sea surface by evaporation and will be able to very play thus a fundamental role in rising with high-altitude of the equatorial air by wet convection after they reach the zone of intertropical convergence. The oceanic trade winds see their speeds frequently reaching 20 km/h.

The climatic phenomenon named El Niño corresponds to a quasi-disappearance of the trade winds in the Western part of the equatorial Pacific. Contrary, the climatic phenomenon named Niña is accompanied by the reinforcement of the trade winds in this same zone of the Pacific.

Simple: Wind#Planetary_wind_belts