The air moves towards the equatorial low-pressure zone, and warms up when it meets the land or ocean. At around 60° this warmed air rises. This is another thermally direct cell.

The Earth's atmospheric circulation varies from year to year, but the large-scale structure of its circulation remains fairly constant. The smaller scale weather systems – mid-latitude depressions, or ...

As warm air rises and cold air sinks it forms three atmospheric circulation cells north of the equator and three to the south. These circulation cells move over land and sea to redistribute the ...

But as air reaches the upper levels of the atmosphere ... This belt of air circulation is referred to as a Hadley cell, after George Hadley, who first described it (Holton 2004).