One aspect of atmospheric dynamics is the trade winds. They have been of great importance, especially since the 15th century, due to their significant influence on sailing ships. However, not many people know what the trade winds are . Even today, many people are drawn to sailing thanks to the trade winds, as they are the winds that blow between the Equator and the tropics. They originate from both the Northern and Southern Hemispheres and are located in the Intertropical Convergence Zone.
In this article we are going to tell you what the trade winds are, what are their characteristics and importance.
What are the trade winds
The trade winds are wind currents that blow almost continuously in summer in the Northern Hemisphere and are more irregular in winter. Their influence is felt between the equator and the tropics, and their north-south latitude reaches approximately 30°. They are moderately strong winds, with an average wind speed of about 20 km/h.
Due to their non-destructive power and apparent stability during the summer, they have historical significance because they facilitate important maritime trade routes. They are also responsible for making it possible to sail across the Atlantic Ocean to the United States. The first to create a detailed map of the trade winds and monsoons was Edmund Halley, who published the map in 1686 in a study using data from British commercial sailors.
The trade winds blow from the northeast (NE) in the Northern Hemisphere to the southwest (SW) at the top of the Earth, and from the southeast (SE) to the northwest (NW) at the bottom of the Earth, that is, in the Southern Hemisphere. Their direction of inclination is due to the Coriolis effect, which causes the Earth's rotation to affect moving objects and alter their motion differently depending on the hemisphere they are in.
Formation of the trade winds
The origin of the trade winds lies in how the sun's rays heat different parts of the Earth in different ways. The formation of the trade winds is summarized below:
- Because the sun's rays have a greater impact during a full impact, that is, vertically, the Earth's equator receives more heat, than is the cause of global warming. As for the trade winds, when the sun's heat falls on the land and waters of the equatorial region, the heat will eventually return to the surface air in large amounts, thereby overheating. This air expands and loses density when heated, becomes lighter, and rises.
- As the hot air rises, cold air from the tropics will fill the void.
- In contrast, hot air that rises near the equator moves toward a latitude of 30º, regardless of the hemisphere in which it is located.
- By the time it reaches this point, most of the air has cooled enough to drop to surface level, forming a closed loop called a Hadley battery.
- However, not all the air will cool down again. A piece is heated again and flows towards the Ferrer battery located between 30º and 60º of latitude, and continues advancing towards the poles.
- The Coriolis effect is the cause that these winds do not blow vertically but obliquely, and the reason why your perception in the two hemispheres is partially reversed.
Also, the meeting point of the trade winds of the two hemispheres, or the small area between them, is called ITCZ, the tropical convergence zone. This area is very important for boaters because it has low pressure and many updrafts. Intermittent heavy rains are very common and their exact location is constantly changing with the evolution of the air mass.
Where they are
As mentioned earlier, trade winds are generated across the entire region, including the area between the equator and 30 degrees north latitude. This has affected many countries. The Canary Islands experience trade winds, partly due to the climate of these Spanish islands. In winter, they were barely affected by the stabilizing effects of the Azores High. Their location near the Tropic of Cancer and their geographical characteristics give them a dry subtropical climate in summer , which, although distant, is similar to that of the Mediterranean Sea.
They also have significant influence on countries like Venezuela, Chile, Colombia, Ecuador, and Costa Rica, all of which are located in tropical regions and have complex climates that attract trade winds. These winds vary significantly depending on the geographic region and specific season. For more information about this atmospheric phenomenon, you can consult the La Niña phenomenon , which also affects weather conditions.
It's important to note that, although trade winds and monsoons are closely related, they are far from the same and should not be confused . Trade winds are gentle, strong, and fairly constant winds, while monsoons are winds with strong, seasonal storms that produce large amounts of precipitation.
Azores anticyclone
The Azores High is named for a reason. It plays a significant role in the Atlantic region where the Azores archipelago is located. Depending on the high's movement, the indirect impact of the trade winds on the Canary Islands can be greater or lesser.
In winter, this anticyclone is very close to the Canary Islands. This leads to greater stability and less trade winds. Therefore, the cold air has little effect on the islands. This is one of the basic factors to maintain a pleasant and warm climate in the colder season.
In summer, the anticyclone migrates over the Azores. The further it is from the Canary Islands, the greater the impact of the trade winds. Therefore, the summer trade winds blow more strongly, preventing temperatures from soaring.
I hope that with this information you can learn more about what are the trade winds and lower their characteristics.