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Unsteady Ekman–Stokes dynamics: implications for surface-wave induced drift of floating marine litter
  • Christopher John Higgins,
  • Jacques Vanneste,
  • Ton van den Bremer
Christopher John Higgins
University of Oxford

Corresponding Author:[email protected]

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Jacques Vanneste
University of Edinburgh
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Ton van den Bremer
Oxford University
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Abstract

We examine Stokes drift and wave-induced transport of floating marine litter on the surface of a rotating ocean with a turbulent mixed layer. Due to Coriolis–Stokes forcing and surface wave stress, a second-order Eulerian-mean flow forms, which must be added to the Stokes drift to obtain the correct Lagrangian velocity. We show that this wave-driven Eulerian-mean flow can be expressed as a convolution between the unsteady Stokes drift and an ‘Ekman–Stokes kernel’. Using this convolution we calculate the unsteady wave-driven contribution to particle transport. We report significant differences in both direction and magnitude of transport when the Eulerian-mean Ekman–Stokes velocity is included.
28 Sep 2020Published in Geophysical Research Letters volume 47 issue 18. 10.1029/2020GL089189