Wave Attenuation in Marginal Ice Zone of Arctic Pack Ice to the North of Spitsbergen
- Aleksey Marchenko (University Centre in Svalbard)
- Document ID
- International Society of Offshore and Polar Engineers
- The 28th International Ocean and Polar Engineering Conference, 10-15 June, Sapporo, Japan
- Publication Date
- Document Type
- Conference Paper
- 2018. International Society of Offshore and Polar Engineers
- boundary layer, attenuation, Waves, ice, method of wave measurements
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- 21 since 2007
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Results of wave measurements in the marginal ice zone of the Arctic pack ice are analyzed and interpreted using a model of wave damping. The model takes into account wave energy dissipation due to the energy transformations inside turbulent boundary layer below the ice. The model includes two parameters one of which is equal to the ratio of the amplitudes of horizontal floe velocities to the horizontal velocities of surface water particles. The second parameter equals the eddy viscosity of water under the ice. Estimates of wave attenuation based on the model considerations are found in a good agreement with the observed wave attenuation.
Penetration of surface waves below floating ice and their action on the ice are under the interest during last years because of a reduction of ice covered areas in the Arctic Ocean. Waves can destroy relatively big areas of solid drift ice in few hours (see, e.g., Collins et al, 2015). Broken ice is more mobile and has less insulating capacity for energy exchange between atmosphere and ocean. Wave amplitudes and lengths are most important characteristics influencing critical bending stresses in ice when it is destroyed by waves. Process of wave attenuation controls wave amplitudes and spectrum depending on the distance to the ice edge.
Wadhams et al (1988) investigated characteristics of wave attenuation process in the marginal ice zone (MIZ) of the Greenland Sea and Bering Sea. Similar processes have been investigated in the Barents Sea by Frankenstein et al (2001), Tsarau et al (2017), Marchenko and Chumakov (2017), and in the Antarctic ice by Meylan et al (2014) and Doble et al (2015). The field measurements demonstrated exponential attenuation of wave amplitudes on the way of their propagation in the ice covered areas. Increments of wave amplitude and wave energy attenuations increase with the increase of wave frequency. The dependence of wave attenuation from wave amplitudes is not significant in most of the cases.
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