What are trade winds and how do they circulate?

Trade winds are permanent east-to-west prevailing winds that flow across Earth's equatorial region, blowing mainly from the northeast in the Northern Hemisphere and the southeast in the Southern Hemisphere. They represent the lower branches of the global Hadley circulation, moving moisture and converging air toward the tropics. Historically utilized by sailing ships for ocean crossings, these winds also transport vital nutrients like Saharan dust across oceans while steering tropical storms.

What we know

• Trade winds are permanent east-to-west prevailing winds flowing in Earth's equatorial region. [1, 2]
• The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere. [2]
• Prevailing trade winds act as a manifestation of the lower branches of the global Hadley circulation. [3]
• Trade winds transport nitrate- and phosphate-rich Saharan dust to Latin America, the Caribbean, and parts of North America. [2]

Where to go next

• what caused itHow does the Hadley circulation drive tropical weather?
• what followedHow do trade winds steer tropical storms and hurricanes?
• how it workedWhat causes the trade wind inversion that caps shallow cumulus clouds?
• a case in pointHow did trade winds enable early European colonization of the Americas?
• compared withHow do atmospheric circulation patterns differ in mid-latitudes compared to the equator?
• an unexpected connectionHow does African desert dust colour North American sunsets?Trade winds carry mineral dust thousands of miles across the Atlantic Ocean from the Sahara Desert, which alters sky coloration and increases red sunsets in Florida.

Sources

• [1]trade wind (Wikidata Q160603) · CC0 1.0
• [2]Trade winds · CC BY-SA 4.0
• [3]Hadley cell · CC BY-SA 4.0
• [4]Atmospheric circulation · CC BY-SA 4.0
• [5]Prevailing winds · CC BY-SA 4.0