What are the characteristics of the trade winds?

With the boats and skippers immersed in the South Atlantic having left the equator behind and with Fernando de Noronha at the bow, there will be many miles ahead to sail with the South East trade winds, with time to think – on the boat, at sea, in themselves: in this world they want to circumnavigate – What will be the challenges they have to face?

The knowledge of the global weather patterns that govern the different Oceans will undoubtedly be a subject that the skippers participating in the Global Solo Challenge (GSC) will surely have deeply studied.

The principal oceans of the globe are the Atlantic, the Indian, the Pacific, the Arctic, and the Antarctic oceans. Two of them, the Atlantic and Pacific oceans, share some similar weather characteristics. The Indian Ocean, at least in its southern part, does as well.

 

As far as the GSC sailors are concerned, they will be primarily affected by the western prevailing wind belt of the southern oceans, and the different meteorological zones of the Atlantic both in the northern and southern hemispheres.

Focusing at the moment while in the Atlantic, they will think about the trade winds that accompany them and what remains of the Atlantic ahead. Concerns for the Indian and Pacific oceans they will leave for later. There is much to think about here in the Atlantic.

The Atlantic is divided into climatic zones depending upon latitude. The most northerly is an area of west winds, immediately to the south of it, an area of variable winds, and then south of that the area of the NE trade winds. South of the NE Trade winds is the so-called Inter-tropical Convergence Zone (ITCZ or what historically was called the doldrums). South of the ITCZ begin the SE trade winds, followed further south by another zone of variable winds.

 

There are two large well-established anticyclones in the Northern and Southern hemispheres of this ocean, that of the Azores in the North and that of St. Helena in the South, each generating its trade winds.

The anticyclone of the Azores “rotates” clockwise, creating the trade winds of the NE in the northern hemisphere; and that of St. Helena that “rotates” counterclockwise, creating the trade winds of the SE in the southern hemisphere.

The yachts of the GSC leaving from La Coruña, will have to sail the area of variable winds; “dropping down” to the trade winds of the NE; cross the ITCZ, and the equator; when they will then enter the area of the trade winds of the SE. They will have to reach the vicinity of Fernando De Noronha off Brazil, then turn and go towards Tristan da Cunha, (entering the zone of variable winds of the southern hemisphere), and then head towards Cape of Good Hope. Once passing the Cape of Good Hope, they will have left the Atlantic at their stern.

 

An important part of the GSC participants’ tour of the world, perhaps the most pleasant in terms of navigation comfort, will undoubtedly be the time spent sailing through the trade winds.

The “Trade Winds” were named by the English and literally meant the winds of commerce as these winds facilitated the historical commercial trading routes used by the beautiful tall ships of the past.

The limits of the trade winds and the inter-tropical convergence zone move north and south, changing both their size and position in latitude. This movement is associated with the Sun’s displacement north to south throughout the year.

 

The meteorology that accompanies the trade winds usually consists of stable winds that oscillate between force 4/5 Beaufort and rarely, but not improbably, those winds can increase to intensities greater than force 7. The skies are normally clear with clusters of cumulus clouds on the horizon, temperatures are pleasant and atmospheric pressure stable, with a slight barometric tide every 12 hours, if the barometer oscillates at a more pronounced level or stops, that is usually a sign of the approach or formation of a tropical storm.

It is always pleasant for a sailboat to be accompanied by these winds, not only for their regularity and the pleasant weather that characterizes them, also because they typically are favorable and take the boats towards their marked course. They will be a part of the voyage that will be enjoyed, and each sailor will try and take advantage of them to make as much headway on the long route to finish the challenge of the GSC.