Figure 2.7 Coriolis effectThe amount of deflection the air makes is directly related to both the speed at
which the air is moving and its latitude. Therefore, slowly blowing winds will be
deflected only a small amount, while stronger winds will be deflected more.
Likewise, winds blowing closer to the poles will be deflected more than winds at
the same speed closer to the equator. The Coriolis force is zero at the equator.
Hadley, Ferrel, and Polar Cells
The worldwide system of winds, which transports warm air from the equator
where solar heating is greatest toward the higher latitudes where solar heating is
diminished, gives rise to Earth’s climatic zones. Three types of air circulation
cells associated with latitude exist—Hadley, Ferrel, and Polar.
HADLEY AIR CIRCULATION CELLS
Air heated near the equator rises and spreads out north and south. After cooling
in the upper atmosphere, the air sinks back to Earth’s surface within the
subtropical climate zone (between 25° and 49° north and south latitudes).
Surface air from subtropical regions returns toward the equator to replace the