| Summary: | International audience A quantitative monitoring of wind-generated wave penetration in the sea ice is now possible with synthetic aperture radars (Ardhuin et al. Remote Sens. Env. 2018, Stopa et al. PNAS 2018). This new data set is providing a deluge of data complementary to the few previous in situ measurements, that is completely changing our understanding of ice impact on ocean waves. In particular, the paradigm of wave scattering by floes or ice thickness variations, which may have been representative of a thick ice Arctic in the 1980s, is now replaced by measurements of wave dissipation with little evidence of scattering. This dissipation is not yet understood but is presumably related to fast cycling of stresses in the ice and, in the presence of pancakes, dissipation in a dual phase solid-liquid system. The new data also clearly shows that wave attenuation can be very strong, releasing a large momentum flux that can be larger than the wind stress over a wide band in the marginal ice zone. That momentum flux is also very heterogeneous, probably due to heterogeneous ice properties, including ice thickness, possibly associated to feedback mechanisms between ice and waves (e.g. Sutherland and Dumont JPO 2018). So far most of the wave-in-ice data available from Sentinel 1 comes from the the Southern Ocean, thanks to the routine acquisition in high resolution IW and wave modes. A few images in the Arctic have allowed to evaluate and adjust parameterizations in wave models (Ardhuin et al. JGR 2018). New data from the SWIM instrument on CFOSAT, launched in October 2018, are bringing measurements of waves in ice in particular in the low incidence beams. These data are presented and discussed. We look forward to the proposed SKIM mission that would measure ice drift, surface current and waves with a Doppler radar. Based on numerical simulations, we expect to observe complex interactions between the near-ice jets, the wave field impinging on the ice, and the momentum flux to the ice layer near the edge, with ...
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