Sea ice floes dissipate the energy of steep ocean waves

Toffoli, Alessandro; Bennetts, Luke G.; Meylan, Michael H.; Cavaliere, Claudio; Alberello, Alberto; Elsnab, John; Monty, Jason

doi:10.1002/2015gl065937

Cited by 58 publications

(59 citation statements)

References 52 publications

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“…Besides, inelastic deformation is expected to occur in large floes or unbroken ice areas and therefore does not explain wave attenuation reported in the first kilometers of the MIZ (Wadhams et al, ). Latter cases could be explained by scattering, friction, floe‐floe collisions, slamming (Bennetts et al, ), and overflow (Toffoli et al, ), but their respective magnitude remains to be quantified in real conditions. These first kilometers of the MIZ, where we expect to find rather small floes, are also likely not compatible with the use of our dispersion relation, which hypothesizes a thin semi‐infinite elastic ice plate.…”

Section: Discussionmentioning

confidence: 99%

Floe Size Effect on Wave‐Ice Interactions: Possible Effects, Implementation in Wave Model, and Evaluation

et al. 2018

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Wind waves may play an important role in the evolution of sea ice. That role is largely determined by how fast the ice layer dissipates the wave energy. The transition from a continuous layer of ice to a series of broken floes is expected to have a strong impact on the several attenuation processes. Here we explore the possible effects of basal friction, scattering, and dissipation within the ice layer. The ice is treated as a single layer that can be fractured in many floes. Dissipation associated with ice flexure is evaluated using an anelastic linear dissipation and a cubic inelastic viscous dissipation. Tests aiming to reproduce a Marginal Ice Zone are used to discuss the effects of each process separately. Attenuation is exponential for friction and scattering. Scattering produces an increase in the wave height near the ice edge and broadens the wave directional spectrum, especially for short-period waves. The nonlinear inelastic dissipation is larger for larger wave heights as long as the ice is not broken. These effects are combined in a realistic simulation of an ice break-up event observed south of Svalbard in 2010. The recorded rapid shift from a strong attenuation to little attenuation when the ice is broken is only reproduced when using a nonlinear dissipation that vanishes when the ice is broken. A preliminary pan-Arctic test of these different parameterizations suggests that inelastic dissipation alone is not enough and requires its combination with basal friction. Key Points:• A spectral wave model with effects of sea ice floe size is presented • Ice breakup is combined with three attenuations processes • Model wave heights for a break-up event reproduce observations in Svalbard apply to wide fields of pancakes that are found in the freezing season and but should rather be representative of waves interacting with solid ice pack. In these conditions, our goal is to explore plausible regimes of wave attenuation in the MIZ, given certain assumptions about wave-ice interaction processes.The different mechanisms that have been proposed to explain wave attenuation in the ice can be represented by source terms in the wave action equation describing the evolution of the wave field (Masson & LeBlond, 1989). The relative importance of the different mechanisms is still unknown in conditions encountered in the natural environment (Squire, 2007). Robin (1963) measured wave attenuation in the Weddel Sea but did not conclude on its possible source, mentioning anelastic dissipation (hysteresis) and basal friction as possible explanations. Wadhams (1973) hypothesized that wave could be dissipated by secondary creep, namely, the inelastic dissipation of waves due to the ice flexure, with a strain rate proportional to the cube of the stress, following the flow law used by Glen (1955) for very slow glacier motions. The work done during and after MIZEX emphasized scattering, that is, multiple reflections of waves by floes, as the dominant source of wave attenuation (Kohout & Meylan, 2008;Kohout et al., 2014;Montiel et...

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Section: Discussionmentioning

confidence: 99%

Floe Size Effect on Wave‐Ice Interactions: Possible Effects, Implementation in Wave Model, and Evaluation

et al. 2018

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“…The RADARSAT‐2 SAR measurements shown here suggest that the wave stripes are still present 200 km from the ice edge along the transect indicated in Figure . As waves propagate through the MIZ, wave energy suffers attenuation and dissipation by scattering interactions and momentum transfer to the ice floes (Doble & Bidlot, ; Kohout et al, ; Meylan & Masson, ; Perrie & Hu, ; Toffoli et al, ; Wadhams, ). Energy transferred from the waves contributes to ice floe motions.…”

Section: Wave Propagation Through Ice In the Mizmentioning

confidence: 99%

Remote Sensing of Waves Propagating in the Marginal Ice Zone by SAR

Shen

Perrie

et al. 2018

JGR Oceans

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Wave‐ice interactions are important in high sea state conditions, when waves propagate from the open ocean into the marginal ice zone (MIZ) and the pack ice. In situ observations of waves and wave‐ice interactions can be obtained at a small number of MIZ locations in costly and challenging experiments, whereas remote sensing using satellite RADARSAT‐2 SAR (synthetic aperture radar) images can observe waves throughout the MIZ, in all weather conditions. We present a methodology to retrieve MIZ wave parameters from polarimetric SAR data. As an application, we describe the characteristics of waves propagating from open water into the MIZ, as generated by a strong low pressure system that developed to the east of Greenland. As waves penetrate the MIZ, SAR remote sensing observations suggest increased dominant wavelengths, attenuated wave energy and shifted mean wave directions. The SAR observations and estimates for retrieved wave attenuation in the MIZ are shown to be consistent with wave attenuation theory and in situ field observations. Thus, valuable estimates of MIZ waves over large spatial scales at high‐resolution are provided by the SAR measurements.

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“…As waves propagate into the ice farther, the cumulative partial-transmission effects by multiple floe edges directly contribute to the exponential decay of the forward-going wave energy (e.g., Kohout and Meylan 2008;Montiel et al 2016). (ii) the dissipative processes such as viscous effects existing in the ice layer and its underlying wave-ice boundary layer (e.g., Liu et al 1991;Keller 1998;Wang and Shen 2010;Voermans et al 2019;Rabault et al 2019), overwash near the floe's front (Skene et al 2015;Toffoli et al 2015), wave-driven floe collisions and breakup (e.g., Collins et al 2015), etc. It is noteworthy that the dissipation mechanism closely depends on the ice type (e.g., grease/pancake ice, ice floe, and continuous ice).…”

Section: Introducing Ice Effects Into Rtementioning

confidence: 99%

Spectral Modeling of Ice-Induced Wave Decay

Liu

Rogers

Babanin

et al. 2020

Journal of Physical Oceanography

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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.

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Sea ice floes dissipate the energy of steep ocean waves

Cited by 58 publications

References 52 publications

Floe Size Effect on Wave‐Ice Interactions: Possible Effects, Implementation in Wave Model, and Evaluation

Floe Size Effect on Wave‐Ice Interactions: Possible Effects, Implementation in Wave Model, and Evaluation

Remote Sensing of Waves Propagating in the Marginal Ice Zone by SAR

Spectral Modeling of Ice-Induced Wave Decay

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