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Abstract

The interactions between surface waves and sea ice are a rich set of scientific problems. For example, wave orbital motions inhibit ice skin-over, Langmuir circulations and turbulence from breaking are thought to advect surface-formed ice crystals into the water column, and wave-driven turbulence affects the vertical heat transfer that controls ice formation. These phenomena are becoming increasingly relevant as decreasing sea ice results in larger waves over a longer season in the Arctic Ocean. Tantalizing numerical simulations have suggested that, for example, observed streak structures of ice on the sea surface are indeed related to wave forcing. However, almost no previous experimental studies have tackled the problem. In this presentation, results from two recent field campaigns will be presented, one in the Arctic (during DarkEdge 2021), and one in the St. Lawrence Estuary (WAAXT 2023), that were specially designed to illuminate the role of waves and wave-driven turbulence on ice formation. These campaigns were conducted in late season during the transition from open water to ice-covered ocean. Using a multi platform approach, including ships, drifting buoys, an autonomous vessel, UAVs, and a research aircraft, it was possible to capture two ice formation events. Waves and wave-driven turbulence were observed to play a key role in the 3-D spatial distribution of sea ice features during the formation stage. This included on streak and band formation, vertical advection of ice crystals, and vertical heat flux for melting and freezing water. The results and their implications will be discussed.