TRADE WINDS: What are they, how do they form and where do they do it?

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The trade winds were extremely important in the centuries from the XV due to their great influence on sailing, and even today there are many who dare to put their sails in their favor. These are winds that occur between the equator and the tropics, blowing from the Northern hemisphere and also from the South, being in the well-known Intertropical Convergence Zone.

If you want to know more about the trade winds and their influence on the climate, keep reading us in this curious article by Green Ecologist in which we explain what are trade winds, how do they form and where do they do it.

What are trade winds - definition and importance

The trade winds are wind currents that blow almost constantly during the Northern Hemisphere summer and more irregularly in the winter. Its effect is given between the equator and the tropics, approximately up to 30º latitude both North and South. They are moderate force winds, with an average speed of about 20 km / h.

Due to their non-destructive force and their marked constancy in the summer months, historically they have had great importance, since they allowed the existence of important maritime trade routes and, in addition, they were also responsible for making it possible to cross the Atlantic to reach America by sailboat. The first to establish a detailed map that included both the trade winds and the monsoons was Edmund Halley, who published it in 1686, in a study that he produced with data from English commercial sailors.

The trade winds blow from NE (Northeast) to SW (Southwest) in the upper part of the planet, the Northern hemisphere, and from SE (Southeast) to NW (Northwest) in the lower part of the Earth, that is, in the southern hemisphere. His oblique direction is due to coriolis effect, which causes the rotation of the Earth to affect moving objects and modify their movement differently depending on the hemisphere in which they are.

How Trade Winds Form - The Process

The origin of the trade winds it is found in how the sun's rays heat different parts of the planet differently. This is the trade wind formation process summarized:

  1. As the influence of solar rays it is much greater when they impact fully, that is, perpendicularly, the Earth's equator receives a greater amount of heat, a circumstance to which it owes its warmer climate. With regard to trade winds, when the sun's heat falls on the lands and waters of the equatorial zone, this heat ends up returning to the surface air in quantity, so it overheats. This air, when heated, expands and loses density, becoming lighter and rising.
  2. To the rising hot air, a void is created that is filled by the coldest airs in the tropics.
  3. In turn, the hot air that has risen near the equator is moving towards 30º latitude, regardless of the hemisphere in which it is located.
  4. By the time it reaches this point, much of that air has cooled enough to descend back to a surface height, giving rise to the closed circuit known as the hadley cell.
  5. However, not all the air cools down again. A part heats up again and circulates towards the ferrel cell, which is between 30º and 60º of latitude, continuing its way towards the poles.
  6. The coriolis effect It is what causes these winds to not blow perpendicularly but obliquely, as well as their senses in the two hemispheres to be partially inverted.

In addition, the point where the trade winds of the two hemispheres meet, or rather the small area between them, is called ITCZ, Intertropical Convergence Zone. This area is of great importance for sailors, as it has low pressures and large upward air flows. In it intermittent torrential rains are common and its exact location constantly changes with the evolution of the air masses.

Where the trade winds occur

The trade winds occur, as we have mentioned, throughout the territory that encompasses the zone between the equator and 30º latitude, both North and South. This affects a large number of countries.

There are trade winds in the Canary Islands, which are partly responsible for the climate of these Spanish islands. In winter they make themselves felt with little force thanks to the stabilizing influence of the Azores anticyclone. Its location near the Tropic of Cancer and its geographical peculiarities give it its subtropical climate of dry summers, similar to the Mediterranean despite the distance.

They also have an important influence in countries such as Venezuela, Chile, Colombia, Ecuador or Costa RicaAll from tropical areas and with complex climates that make the trade winds blow in them with marked differences depending on the specific geographical area and the season of the year.

Keep in mind that, although lthe trade winds and monsoons they are closely related, are far from the same, and should not be confused. The trade winds are moderate and fairly constant force winds, while the monsoons are winds with heavy seasonal storms that discharge enormous amounts of precipitation. Learn more about these in this other post about What are monsoons, types and consequences.

If you liked discovering all this about what trade winds are and how they form, we recommend you discover other types of winds with these other articles by Green Ecologist about the Types of winds in Spain and What is the solar wind and how it affects the Earth.

If you want to read more articles similar to Trade winds: what are they and how are they formedWe recommend that you enter our Nature Curiosities category.

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