Surface waves and sea ice interactions control most of polar sea ice dynamics, affecting sea ice fracture, Floe Size Distribution (FSD), ice formation and ice-ocean-atmosphere fluxes. Such interactions take place in complex areas made of fragmented sea ice called Marginal Ice Zones (MIZ). In order to improve our understanding of surface waves propagation through this complex, multi-scale medium, we operated several field measurements campains in the St. Lawrence estuary, near Rimouski, Canada. In order to characterize both waves propagation and sea ice properties, we designed new methods based on different instruments such as Unmanned Aerial Vehicles (UAV), wave buoys, geophones and optical fiber. I propose to present you two of these methods which are described below.
Thanks to several UAV, digital image correlations and geometric projections, we precisely measure the waves velocity field during a wave-induced ice break-up event generated by an icebreaker nearby continuous sea ice. This UAV-based measurement is in good agreement with wave buoys placed on the ice before the fracture, enabling to get the wave amplitude over a grid of 106×75 meters with a high spatio-temporal sampling.
In February 2025, we deployed a 600 meters long optical fiber across three different morphological sea ice conditions. Once connected to a laser interrogator unit and mechanically coupled to the ice, this cable can monitor strain field propagation through the ice, using a technique called Distributed Acoustic Sensing (DAS). During hour-long recordings, we measured the propagation of both multi-modal seismic signals generated by active sources and hydro-elastic swell. Thanks to the dispersion of these elastic waves, we identify the ice mechanical properties in each sea ice area.
