Winds can also generate vertical water motions by processes called upwelling and downwelling.
This process is called Ekman transport and is a result of the Coriolis effect. In the Southern Hemisphere, surface water is deflected to the left of the wind's motion. Where winds cause the surface water to move toward a coastline or to converge with another water mass, the surface water will try to move downward to create a downwelling current. Where winds cause the surface water to move away from a coastline or to diverge from another surface water mass, deeper water will move up to the ocean surface, creating an upwelling current. For example, northerly winds are common in the summer along the California coast.