The Ekman Spiral

arrows represent water movement

As wind blows over the surface layer of water, friction between the two pulls the water forward. As we know, when water (and other objects) moves across Earth’s surface it bends due to the Coriolis Effect. The top most layer of water will bend away from the direction of the wind at about 45 degrees. For simplicity, we will assume that this scenario is in the Northern Hemisphere and all movement bends to the right. As the top layer of water begins to travel, it in turn pulls on the water layer beneath it, just as the wind had. Now this second water layer begins to move, and it travels in a direction slightly to the right of the layer above it. This effect continues layer by layer as you move down from the surface, creating a spiral effect in the moving water.

Tags: Currents