Anti-trade winds are the upper branch of the Hadley cell. While trade winds carry surface air toward the equator, anti-trades return that air aloft (8–15 km) towards subtropical latitudes, where it descends to close the circulation.
Link to the subtropical jet
Anti-trades are closely linked to the subtropical jet stream, which marks where descending air accumulates. As it descends, the air compresses and warms, creating the great subtropical deserts (Sahara, Kalahari, Atacama). Their intensity varies with seasons and with phenomena like El Niño.