A Computational Fluid Dynamics Model for the Small-Scale Dynamics of Wave, Ice Floe and Interstitial Grease Ice Interaction

Abstract

The marginal ice zone is a highly dynamical region where sea ice and ocean waves interact. Large-scale sea ice models only compute domain-averaged responses. As the majority of the marginal ice zone consists of mobile ice floes surrounded by grease ice, finer-scale modelling is needed to resolve variations of its mechanical properties, wave-induced pressure gradients and drag forces acting on the ice floes. A novel computational fluid dynamics approach is presented that considers the heterogeneous sea ice material composition and accounts for the wave-ice interaction dynamics. Results show, after comparing three realistic sea ice layouts with similar concentration and floe diameter, that the discrepancy between the domain-averaged temporal stress and strain rate evolutions increases for decreasing wave period. Furthermore, strain rate and viscosity are mostly affected by the variability of ice floe shape and diameter.

Diffusion of gravity waves by random space inhomogeneities in pancake-ice fields. Theory and validation with wave buoys and synthetic aperture radar

“…In the scattering-based approach of 47 The attenuation rates predicted by the two scattering-based approaches are well-aligned only for waves longer than 200 m, for which the flexural rigidity of the sea ice is expected to be negligible. This behavior for very long waves is consistent with computational fluid dynamics simulations that consider the heterogeneous sea ice material composition and account for the wave-ice interaction dynamics 48 . Numerical results therein suggest that the mechanical sea ice response becomes independent of the detailed distribution of pancakes for wave number smaller than 0.016 m −1 .…”

“…We can then use the value of λ from analysis of the SAR images to carry out a best-fit of the buoy data on wave attenuation with Eqs. (57) and (48), to retrieve the values of the remaining parameters ϕ inc and h2 :…”

“…Black lines show attenuation rates computed with Eqs. (48,57). The top panels show the attenuation rates measured at 15:30 UTC, and thus related to the CSK acquisition, while the bottom panels show the attenuation rates measured at 17:00 UTC and 17:30 UTC, and are related to the S1 acquisition.…”

Direct Observations of Wave‐Sea Ice Interactions in the Antarctic Marginal Ice Zone

“…The cold air temperature during the winter deployment provide a strong heat flux out of the ocean, leading to grease ice in between and possibly below the ice floes. Interstitial grease ice has been hypothesized to affect the attenuation rate (Marquart et al., 2021). As discussed by De Carolis et al.…”

“…The cold air temperature during the winter deployment provide a strong heat flux out of the ocean, leading to grease ice in between and possibly below the ice floes. Interstitial grease ice has been hypothesized to affect the attenuation rate (Marquart et al, 2021). As discussed by De Carolis et al ( 2021), presence of grease ice below the floes would also cause an effective ice thickness larger than the observed floe thickness, and therefore a stronger wave attenuation, which could explain the difference in attenuation between winter and spring.…”