Editing Fundamentals of Meteorology (section)

== Global Atmospheric Circulation Cells ==

If the Earth did not rotate, this heat transfer would be a simple, continuous loop: hot air would rise at the equator, travel all the way to the poles, cool, sink, and travel back along the surface. However, Earth's rotation breaks this flow into three distinct latitudinal circulation bands known as cells.

=== The Hadley Cell ===
Located between the equator and approximately 30 degrees latitude (North and South), the Hadley cell is driven by intense tropical heating. Warm, moist air rises at the equator, creating a band of low pressure and heavy precipitation known as the Intertropical Convergence Zone (ITCZ). As this air reaches the top of the troposphere, it moves poleward, cooling as it travels. By the time it reaches roughly 30 degrees latitude, the air is cold, dry, and dense. It sinks back to the surface, creating high-pressure zones that are responsible for most of the world's major deserts (such as the Sahara). 

=== The Polar Cell ===
Operating from roughly 60 degrees latitude to the poles (90 degrees), the Polar cell is the smallest and weakest of the three. Intensely cold, dense air sinks at the poles, creating high surface pressure. This air flows equatorward along the surface until it reaches about 60 degrees latitude, where it meets warmer air moving up from the mid-latitudes, is forced to rise, and returns toward the poles aloft.

=== The Ferrel Cell ===
Situated between 30 and 60 degrees latitude, the Ferrel cell acts as a transitional gear between the Hadley and Polar cells. Unlike the other two, it is not directly driven by temperature gradients but is instead forced into motion by the descending air of the Hadley cell and the rising air of the Polar cell. Surface air in the Ferrel cell moves poleward and rises at 60 degrees, while high-altitude air moves equatorward and sinks at 30 degrees.