Modelled Stokes drift in the Marginal ice zones of the Arctic Ocean

Abstract

<p>The Stokes drift in the marginal ice zones (MIZ) of the Arctic Ocean is modelled by WAVEWATCH III. Applying two viscoelastic and one empirical frequency-dependent wave-ice models, the modelled wave parameters and spectrum are compared with field observations in the Beaufort-Chukchi Sea. Three wave-ice parameterizations show similar abilities to produce the surface Stokes drift estimated from buoy measurements. By using five-year (2015-2019) hindcasted directional spectra of the autumn Arctic, we present and discuss the monthly mean surface Stokes drift (1-10 cm/s), e-folding depth (1-14 m) and vertically integrated transport (0.1-0.4 m2/s) in the marginal ice zones, which are stronger in October than in September. When bulk wave parameters are adopted to estimate the Stokes drift fields, the surface Stokes drift will be underestimated by about 44-59% with mean ice concentration smaller than 60%, and the Stokes e-folding depth will be overestimated by about 1.4 to 5.0 times increasing from the interior to the edge of the ice cover. Since the Stokes drift may be an important component of the total surface current, we compare the modelled surface Stokes drift with the Eulerian current from reanalysis data, which shows that the mean surface Stokes drift is typically about 30% of the Eulerian current over large parts of the MIZ in Arctic Ocean, and is of the same order or even larger in some sea areas of the Chukchi, E. Siberian and Laptev Seas. It indicates that the Stokes drift is necessary to be considered to better model the dynamic processes of the sea ice, especially for the drift of ice floes.</p>