Change of current speed in the Ekman layer (full red line) and in the logarithmic layer (broken blue line). The inset shows the first 2 meters above the bottom enlarged. Absolute speeds and depths are shown as an example but otherwise arbitrary.

As the figure shows, the difference in speed between the logarithmic layer and the Ekman layer is only slight. The main difference is in direction: The current in the logarithmic layer does not rotate with depth. This is not seen in a diagram of current speed.

In the ocean, the logarithmic layer is incoporated into the Ekman layer as a sub-layer, ie the current does not rotate over the first few meters and current speed follows the blue curve, before it continues with the red profile and exhibits the Ekman spiral structure.

© 1996 M. Tomczak

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