Wind Waves in Sea Ice of the Western Arctic and a Global Coupled Wave-Ice Model

Abstract

The retreat of Arctic sea ice is enabling increased ocean wave activity at the ice edge, yet the interactions between surface waves and sea ice are not fully understood. Here, we examine in situ observations of wave spectra spanning 2012-2021 in the western Arctic marginal ice zone (MIZ). Swell waves are rarely observed beyond 100 km inside the MIZ. However, local wind waves are observed forming in patches of open water amid partial ice cover during summer. These local waves remain fetch-limited between ice floes with heights less than 1 m. To investigate the physics of these waves, we conduct experiments varying wave attenuation and generation in ice in a global model with coupled interactions between waves and sea ice. A weak high-frequency attenuation rate is required to simulate the wind waves reported in observations. The choice of attenuation scheme and the wind input in ice have a remarkable impact on the extent of wave activity in sea ice across polar oceans, particularly in the Southern Hemisphere. As well as demonstrating the need for stronger constraints on wave attenuation, our results suggest further attention should be paid to locally generated wind waves and their role in sea ice evolution.