Global wind patterns are created by the uneven heating of the Earths surface, which drives large global wind systems that, in turn, drive the oceans surface currents. These wind patterns are important to life as they help control where it rains, what kinds of species can survive in an area, and even where tropical rainforests and deserts are located. The three major global wind belts are polar easterlies, westerlies, and trade winds. The key features of global wind patterns are:
-
Hadley Cells: These are circulation cells that circulate air through the atmosphere from the surface to high altitudes and back again. The cells on either side of the Equator are called Hadley cells and give rise to the Trade Winds at Earths surface.
-
Coriolis Effect: This is the apparent shift in the path of any fluid or object moving about the surface of the Earth due to the rotation of the Earth. All winds in the Northern Hemisphere appear to curve to the right as they move, while in the southern hemisphere, winds appear to curve to the left.
-
Intertropical Convergence Zone (ITCZ): This is a broad east to west area of light winds around the equator where the trade winds converge. This belt of air around the equator receives much of the sun’s radiant energy and is the area with the most active weather.
-
Doldrums: This is another name for the ITCZ, where there are light winds due to the convergence of the trade winds.
-
Polar Cells: These are circulation cells that are located between 60 and 90 degrees latitude in both hemispheres. They are responsible for the polar easterlies.
-
Westerlies: These are the prevailing winds that blow from west to east in the middle latitudes between 30 and 60 degrees latitude in both hemispheres.
-
Trade Winds: These are steady winds that blow from east to west between 30 degrees latitude and the equator in both hemispheres.
Global wind patterns are even more complicated than the overall model, and they are influenced by many factors, including the Earths rotation, the suns radiation, and the Coriolis effect.
