Transformation of internal solitary waves under ridged ice cover
Internal wave-driven mixing is an important factor in the balance of heat and salt fluxes in the polar regions of the ocean. The breaking internal waves at the edge of the ice cover can essentially enhance the mixing and melting of ice in the Arctic Ocean and Antarctica. The internal solitary waves...
| Main Authors: | , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus Publications
2023
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/egusphere-2023-1992 https://noa.gwlb.de/receive/cop_mods_00068890 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00067300/egusphere-2023-1992.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1992/egusphere-2023-1992.pdf |
| Summary: | Internal wave-driven mixing is an important factor in the balance of heat and salt fluxes in the polar regions of the ocean. The breaking internal waves at the edge of the ice cover can essentially enhance the mixing and melting of ice in the Arctic Ocean and Antarctica. The internal solitary waves (ISWs) are generated by various sources, including tidal currents over the bottom topography, the interaction of ice keels with tides, varying in time wind, vortices, and lee waves. In the study, a numerical investigation of the transformation of ISW propagating from open water in the stratified sea under the edge of the ice cover is carried out to compare the depression ISW transformation and loss of energy on smooth ice surfaces, including those on the ice shelf and glacier outlets, with the processes beneath the ridged underside of the ice. They were carried out using a nonhydrostatic model which is based on the Reynolds averaged Navier-Stokes equations in the Boussinesq approximation for a continuously stratified fluid. The Smagorinsky turbulence model extended for stratified fluid was used to explicitly describe the small-scale turbulent mixing. Two series of numerical experiments were carried out in an idealized 2D setup. The first series aimed to study processes of the ISW-depression transformation under ice cover of constant submerged ice thickness. A loss of energy was estimated based on the budget of depth-integrated pseudoenergy before and after the wave transformation. The transformation of depression ISW is controlled by the blocking parameter β. For large positive and large negative values of parameter β which is the ratio of the height of the minimum depth of the upper layer under the ice cover to the incident wave amplitude. The energy loss was relatively small for large positive and large negative values of β. The maximal value of energy loss was about 38 % and it is reached at β ≈ 0 for ISW. In the second series of experiments, a number of keels were located underside of the ice layer of constant ... |
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