Approximate Stokes Drift Profiles in Deep Water

TL;DR

This paper introduces a new deep-water approximation for Stokes drift profiles that improves accuracy over traditional monochromatic models, with significant implications for ocean circulation and turbulence modeling.

Contribution

It presents an alternative Stokes drift profile relying on Stokes transport and surface drift, offering better agreement with observed spectra without extra computational cost.

Findings

Better match with complex wave spectra than monochromatic profiles

More accurate shear profiles impacting ocean circulation models

No additional computational cost compared to traditional models

Abstract

A deep-water approximation to the Stokes drift velocity profile is explored as an alternative to the monochromatic profile. The alternative profile investigated relies on the same two quantities required for the monochromatic profile, viz the Stokes transport and the surface Stokes drift velocity. Comparisons with parametric spectra and profiles under wave spectra from the ERA-Interim reanalysis and buoy observations reveal much better agreement than the monochromatic profile even for complex sea states. That the profile gives a closer match and a more correct shear has implications for ocean circulation models since the Coriolis-Stokes force depends on the magnitude and direction of the Stokes drift profile and Langmuir turbulence parameterizations depend sensitively on the shear of the profile. The alternative profile comes at no added numerical cost compared to the monochromatic profile.