Interactions Between Internal Solitary Waves and Sea Ice

Internal Solitary Waves (ISWs) that form on internal density interfaces in the ocean are responsible for the horizontal transport and vertical mixing of heat, nutrients, and other water properties. The waves also induce fluid motion that can induce stresses and motion on floating structures, such as sea ice. This study investigates ISW-sea ice interactions. Using laboratory experiments, ISWs generated via the lock gate technique are observed interacting with weighted floats of varying sizes. The motion of these floats can be modeled effectively, simply as the average velocity of the fluid under the float, and it is found that when floats are small relative to the wavelength, they behave in the same manner as a fluid particle, but as floats become bigger relative to the wavelength, the maximum velocity decreases, and interaction time increases. This phenomenon is explained simply by the wave-induced flow as opposed to energy transfer arguments. By using this model with a large sample of theoretical waves, the float motion is parameterized based on the float length and wave parameters. Whilst small floats do not disrupt the flow patterns, the wave-induced flow under larger floats forms a pair of counter-rotating vortices at each end of the float. The formation and evolution of these flow features arise as a result of boundary layer separation with the horizontal wave-induced flow relative to the float velocity. This reveals complex dynamics due to the non-stationary behavior of both the float and flow. Underwater waves are found in oceans across the world, including in areas with sea ice. They help mix heat, salt and other constituents in the ocean between deep and shallow waters. The Arctic is changing quickly, with summer sea ice extent declining 12.6% per decade, so we are now finding internal waves in newly ice-free areas. Experiments are used to understand how these waves interact with sea ice. It is found that bigger floats move more slowly and create more flow disturbance, albeit not enough to cause mixing. The way this flow behaves is complicated by the movement of both the model ice, and the wave. Further experimental work is needed to understand the impact of changing the thickness, concentration and shape of the ice on the behavior of these waves. Internal Solitary Waves (ISWs) can interact with sea ice in the Arctic Ocean. This process is modeled using laboratory experimentsThe wave-induced motion of ice is slower when the ice length is large in comparison to the wave, a result explained by the wave form aloneVortices form at the ice edge. They are boundary layer features that depend on the motion of both the ice and ISW