Spectral Modeling of Ice-Induced Wave Decay

Abstract

Three dissipative (two viscoelastic and one viscous) ice models are implemented in the spectral wave model WAVEWATCH III to estimate the ice-induced wave attenuation rate. These models are then explored and intercompared through hindcasts of two field cases: one in the autumn Beaufort Sea in 2015 and the other in the Antarctic marginal ice zone (MIZ) in 2012. The capability of these dissipative models, along with their limitations and applicability to operational forecasts, are analyzed and discussed. The sensitivity of the simulated wave height to different source terms—the ice-induced wave decay Sice and other physical processes Sother (e.g., wind input, nonlinear four-wave interactions)—is also investigated. For the Antarctic MIZ experiment, Sother is found to be remarkably less than Sice and thus contributes little to the simulated significant wave height Hs. The saturation of dHs/dx at large wave heights in this case, as reported by a previous study, is well reproduced by the three dissipative ice models with or without the utilization of Sother in the ice-infested seas. A clear downward trend in the peak frequency fp is found as Hs increases. As fp decreases, the dominant wave components of a wave spectrum will experience reduced damping by sea ice, and finally result in the flattening of dHs/dx for Hs > 3 m in this specific case. Nonetheless, Sother should not be disregarded within a more general modeling perspective, as our simulations suggest Sother could be comparable to Sice in the Beaufort Sea case where wave and ice conditions are remarkably different.

Experimental evidence for a universal threshold characterizing wave-induced sea ice break-up

“…The observational threshold value I br ≈ 0.014, which separates the break-up from the non-break-up events, is indicated by the dashed line. Liu et al, 2020), therefore, thin ice is generally exposed to more wave energy, including shorter wavelengths. Moreover, there are still significant uncertainties in the actual mechanical properties of very thin ice relative to thicker ice.…”

Experimental evidence for a universal threshold characterizing wave-induced sea ice break-up

“…Waves can, however, still play a critical role in the break-up of thin ice. For instance, thick ice attenuates wave energy more strongly than thin ice (e.g., Doble et al, 2015;Liu et al, 2020), therefore, thin ice is generally exposed to more wave energy, including shorter wavelengths. Moreover, there are still significant uncertainties in the actual mechanical properties of very thin ice relative to thicker ice.…”

Sea Ice Retreat Contributes to Projected Increases in Extreme Arctic Ocean Surface Waves

“…This is an area of active research under continuous development (Squire, 2020). When more information about the sea ice state is available, typically at shorter time and/or spatial scales, more complex ice‐wave interaction approaches might be implemented (e.g., Boutin et al, 2020; Doble & Bidlot, 2013; Liu et al, 2020). However, given the limited knowledge and large uncertainty of the sea ice climatology in the future projections (Shu et al, 2015), the implemented SIC approach in this study is reasonable and similar to those used in wave simulations at similar spatial and temporal scales (e.g., wave projections by Khon et al, 2014, and CFSR and ERA5 historical products).…”