BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Internal Solitary Waves and their interaction with sea ice - Magda Carr (Newcastle University) DTSTART:20220927T083000Z DTEND:20220927T090000Z UID:TALK178373@talks.cam.ac.uk DESCRIPTION:Oceanic internal waves (IWs) propagate along density interface s and are ubiquitous in stratified water. Their properties are influenced strongly by the nature and form of the upper and lower bounding surfaces o f the containing basin(s) in which they propagate. \; As the Arctic Oc ean evolves to a seasonally more ice-free state\, the IW field will be aff ected by the change at the surface. The relationship between IW dynamics a nd ice is important in understanding (i) the general circulation and therm odynamics in the Arctic Ocean and (ii) local mixing processes that supply heat and nutrients from depth into upper layers\, especially the photic zo ne. This\, in turn\, has important ramifications for sea ice formation pro cesses and the state of local and regional ecosystems. \;\nAn experime ntal study of internal solitary waves (ISWs) propagating in a stably strat ified two-layer fluid in which the upper boundary condition changes from o pen water to ice is presented. Grease\, level and nilas ice are considered . The experiments show that the internal wave-induced flow at the surface is capable of transporting sea-ice in the horizontal direction. In the lev el ice case\, the transport speed of\, relatively long ice floes\, nondime nsionalized by the wave speed is linearly dependent on the length of the i ce floe nondimensionalized by the wavelength. It will also be shown that b ottom roughness associated with different ice types can cause varying degr ees of vorticity and small-scale turbulence in the wave-induced boundary l ayer beneath the ice. Measures of turbulent kinetic energy dissipation und er the ice are\, shown to be comparable to those at the wave density inter face. Moreover\, in cases where the ice floe protrudes into the pycnocline \, interaction with the ice edge can cause the ISW to break or even be des troyed by the process. The results suggest that interaction between ISWs a nd sea ice may be an important mechanism for dissipation of ISW energy in the Arctic Ocean.\nPreliminary results from Particle Tracking Velocimetry measurements of experiments using floating polystyrene discs (with the sam e density as sea ice &rho\; = 910kg/m3 ) will also be presented. The motio n of these discs is compared to the output of a simple numerical model\, i n order to quantify how ice moves in response to the near-surface internal wave-induced flow.\nAcknowledgements\nThis work was funded through the EU Horizon 2020 Research and Innovation Programme Hydralab+ and by the Natur al Environment Research Council (NERC) funded ONE Planet Doctoral Training Partnership (grant number [NE/S007512/1]).\nReferences\nCarr M\, Sutherla nd P\, Haase A\, Evers K-U\, Fer I\, Jensen A\, Kalisch H\, Berntsen J\, P arau E\, Thiem O\, Davies PA. \;Laboratory Experiments on Internal Sol itary Waves in Ice-Covered Waters. \;Geophysical Research Letters  \;2019\, \;46(21)\, 12230-12238. LOCATION:Seminar Room 1\, Newton Institute END:VEVENT END:VCALENDAR