Wind-driven surface currents affect water to a depth of approximately how many meters?

Wind-driven surface currents affect water to a depth of approximately how many meters?

• A. Several hundred meters
• B. Several dozen meters
• C. Several thousand meters
• D. At surface only

Answer: (A)

Wind adds shear at the ocean surface and, through turbulence and the Coriolis effect, drags the water in the upper part of the water column. The influence isn’t confined to the surface; it penetrates downward to a depth known as the Ekman layer, which in typical conditions extends to roughly a few hundred meters. That’s why wind-driven surface currents affect water to about several hundred meters. The options that limit the effect to the surface, or that place it far shallower or much deeper than air–water friction and rotation would generally produce, don’t fit this broader, but still upper-layer, influence.

Wind adds shear at the ocean surface and, through turbulence and the Coriolis effect, drags the water in the upper part of the water column. The influence isn’t confined to the surface; it penetrates downward to a depth known as the Ekman layer, which in typical conditions extends to roughly a few hundred meters. That’s why wind-driven surface currents affect water to about several hundred meters. The options that limit the effect to the surface, or that place it far shallower or much deeper than air–water friction and rotation would generally produce, don’t fit this broader, but still upper-layer, influence.