Interactions Between Internal Solitary Waves and Sea Ice

Abstract

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.

Experimental study of internal solitary wave evolution beneath an ice keel model

“…A study on the interaction of ISW with an ice sheet by Carr et al (2019) reported that an ice sheet protruding into the pycnocline may cause distortion or even breaking of ISW. Hartharn-Evans et al (2024) investigated the interactions between ISWs and free-floating objects representing sea ice and found that float velocity was dependent on both the amplitude of the wave and the length of the float. At present, there is only a limited number of studies on the interaction between ISWs and ice keels in the laboratory, and previous researchers mainly focused on the motion state of ice, leading to a lack of clarity regarding the characteristics of wave -flow field, and energy of ISWs.…”