[A-OS04] Ocean Mixing Frontiers

[AOS04-P06] Impacts of wave spreading and multidirectional waves on estimating Stokes drift

*Adrean Webb¹, Baylor Fox-Kemper² (1.The University of Tokyo, Dept. of Ocean Technology, Policy, and Environment, Kashiwa, Chiba, Japan, 2.Brown University, Dept. of Earth, Environmental, and Planetary Sciences, Providence, RI, USA)

Keywords:Stokes drift, unidirectional waves, wave spreading

The Stokes drift velocity is an important quantity in categorizing the
effects of ocean surface gravity waves and is increasingly used in
models to parametrize wave-driven mixing or calculate sea surface
transport. However, it is often overlooked that Stokes drift for a
random sea is not easily generated from wind and wave data and large
differences exist even between 1D and 2D spectral approximations. It
is important to rectify these differences in order to compare model
results and improve understanding.
Here, it will be shown that differences in Stokes drift magnitude and
direction depend mainly on the interaction of different wave groups
and the process of wave spreading. To illustrate, we will review
various Stokes drift approximations and introduce a new 1D spectral
approximation to include the systematic effects of wave spreading.
This new approximation will be used with observational and global
model data (buoy located at Ocean Weather Station P and WAVEWATCH III
output respectively) to separate and quantify wave spreading and
multidirectional wave effects on Stokes drift.