Trade Winds and Rainfall During A Normal Year

• During a normal year, the easterly trade winds push and pile the water in the equatorial pacific into the western part of the pacific basin.
• The sea level is actually higher in the western pacific
• Also note the upward motion and precipitation associated with the warm water and lower pressure in the western pacific
• Also note the cooler water, high pressure and subsidence in the eastern Pacific.
• The large-scale zonal circulation in the equatorial plane is called the Walker Circulation.