The major power source for winds on the earth is the sun, which heats the equatorial regions significantly more than the polar ones. What this means is that air in the equatorial regions is warmed while the air in the polar regions cools. The low-latitude warm air expands and rises (think of steam rising from a tea kettle) and heads toward the poles, creating what is termed a Hadley Cell. Meanwhile, the high-latitude (polar) air has cooled and become denser, sinks, and flows toward the equator, creating a Polar