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In the equator large hot air masses rise to the upper layers of the atmosphere and move towards the Poles (Earth's higher latitudes) where the temperatures are colder. In the Northern Hemisphere, at around 30° latitude because of the rotation of the Earth (the Coriolis force), these air masses are deviated clockwise and begin sinking down creating a high pressure area (called Anticyclone) over the North Atlantic Ocean.
 Hence, winds generated over the equator revolve clockwise around the North Atlantic Ocean's high pressure area. Since they are largely driven by the globe's temperature differences which translate into atmospheric pressure differences, these winds are considered global winds.
The "trade winds" as they are being called are not influenced by the topography of the earth surfaces, resulting instead from the combined influences of the rotation of the earth (Coriolis forces) and its temperature differences from equator to poles. The later are due to the effect of solar radiation incidence angles on a spherical surface. These cannot be the same on the center of a sphere (earth's equator) versus its extremes (the poles). It may be relevant to mention that these fundamentals cannot change, regardless of any climate change considerations, so long that the earth is round and rotates while exposed to direct solar radiation.  Geological evidence provided by the existence of the world’s largest sedimentary phosphate deposits (42 % of World reserve base*) that have been trapped at the bottom of Morocco’s Atlas Mountain range further to the North, confirm that the trade winds that are shaping oceanic currents in the exact same pathways, have been there for millions of years.
Indeed, high marine biological productivity associated with upwelling ocean currents along continental margins brought phosphorus-rich cold waters from deeper ocean levels nearer to the surface. This nourishes and stimulates growth of plants and animals whose remains accumulated on the sea bottom. The concentrations of phosphorus-rich organic debris covering thousands of square kilometers drifted away towards this area to be trapped by North Africa's Atlas mountain range. These, highlighted by the yellow triangles shown on the map to the left (over Khouribga, Benguérir and Youssoufia respectively) have accumulated over millions of years to become the largest phosphate-rock deposits that are mined today. Further to the South, on the African coast and the junction between the Sahara desert with the Atlantic Ocean, the trade winds are creating a zone of global energy exchange caracterized by a dry climate dominated by steady winds. Indeed, thermal winds generated daily over the Sahara's hot surfaces are actually superimposed upon the larger trade wind system coming from the Atlantic. This generates one of the largest and steadiest wind systems available on earth. The North to North East wind directions resulting from the merging of these global and local effects are typical for a Trade Wind region. The Trade Winds are actually the main factor responsible for the Sahara's extreme dryness by moving away the clouds from the ocean. The Trade Winds have been known for centuries. During the Age of Sail, the pattern of these prevailing winds determined transatlantic sailing routes impacting thereby the history of European empire-building and most of the world's modern political geography. The trade winds shaped the vast majority of the Saharan coastline into inert rocky plateaus, called "Hammadas".
Wind speeds have been accurately monitored on several sites in Morocco and Mauritania in order to confirm the scale of the aforementioned wind resource. (*) Source: United States Geological Survey - Geology and Nonfuel Mineral Deposits of Africa and the Middle East - 2009
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Resource / Trade Winds 
