The Walker Cell
The Walker Cell: The Walker circulation is the result of a difference in surface pressure and temperature over the western and eastern tropical Pacific Ocean. A pressure gradient from east to west and causes surface air to from high pressure in the eastern Pacific to low pressure in the western Pacific. Higher up in the atmosphere, west-to-east winds complete the circulation. The Walker circulation affects precipitation patterns in many locations, including the Southwest, and influences the easterly trade winds, oceanic upwelling, and ocean biological productivity. It also provides the background against which El Niño-Southern Oscillation (ENSO) events take place.
Credit: Figure courtesy of United Nations Environmental Program, GRID-Arendal Maps and Graphics Library; A portion of the caption provided with permission from the University Corporation for Atmospheric Research. http://www.unep.org/