9.5: Langmuir Circulation

Measurements of surface currents show that winds generate more than Ekman and inertial currents at the sea surface. They also generate a Langmuir circulation (Langmuir, 1938), a current that spirals around an axis parallel to the wind direction. Weller et al. (1985) observed such a flow during an experiment to measure the wind-driven circulation in the upper 50 meters of the sea. They found that during a period when the wind speed was 14 m/s, surface currents were organized into Langmuir cells spaced 20 m apart, the cells were aligned at an angle of 15\(^{\circ}\) to the right of the wind, and vertical velocity at 23 m depth was concentrated in narrow jets under the areas of surface convergence (figure \(\PageIndex{1}\)). Maximum vertical velocity was \(-0.18 \ \text{m/s}\). The seasonal thermocline was at 50 m, and no downward velocity was observed in or below the thermocline.

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