Trade Winds During an El Nino Year

• During an El Nino year, the trade winds weaken
• This allows the water in the western pacific to move to the eastern pacific in the form of a "kelvin wave"
• The equatorial counter current is also stronger
• Notice the change in the Walker Circulation and associated precipitation distribution.
• What causes the changes in trade winds, sea-surface temperatures, and pressure patterns in the equatorial pacific is still not known....., can you believe it????