Global winds and Coriolis effect, illustration. The rotation of the Earth and the Coriolis effect causes the wind patterns shown. The prevailing winds (lower right) are the trade winds (tropical easterlies), mid-latitude westerlies, and the polar easterlies. The corresponding cells (upper left) are the Hadley cells, Ferrel cells, and polar cells. Between these regions are the high-altitude tropical, subtropical and polar jetstreams (upper right and lower left).