What causes ocean currents?

Strong and predictable winds, like the trade winds, are one of the major forces which drive the Pacific currents. Winds are particularly important in driving surface currents, while deep-water currents are driven by convection, which results from temperature differences between water layers. Convection occurs when ocean water heats up and becomes less dense, and rises. This water moves above the cooler water, and gives off its heat to the surrounding environment. As it cools, it begins to sink, and the process is repeated. Convection results in a continual circulation of ocean water.

Click on the links below to learn more about the currents in the Pacific Ocean:

Driving forces of currents El Niño
Measuring the flow of currents La Niña
North Pacific currents