Sea ice floes dissipate the energy of steep ocean waves

TL;DR

This study investigates how sea ice floes dissipate energy from steep ocean waves, revealing that nonlinear effects become significant with energetic waves, which are not captured by traditional linear models.

Contribution

The paper introduces an experimental model for wave attenuation by a single ice floe and compares it with linear predictions, highlighting the importance of nonlinear effects in energetic wave conditions.

Findings

Linear models work well for gentle waves

Overprediction occurs for energetic waves

Wave-ice interactions like floe over wash enhance dissipation

Abstract

Wave attenuation by ice floes is an important parameter for modelling the Arctic Oceans. At present, attenuation coefficients are extracted from linear models as a function of the incident wave period and floe thickness. Recent explorations in the Antarctic Mixed Ice Zone (MIZ) revealed a further dependence on wave amplitude, suggesting that nonlinear contributions are non-negligible. An experimental model for wave attenuation by a single ice floe in a wave flume is here presented. Observations are compared with linear predictions based on wave scattering. Results indicate that linear models perform well under the effect of gently sloping waves. For more energetic wave fields, however, transmitted wave height is normally over predicted. Deviations from linearity appear to be related to an enhancement of wave dissipation induced by unaccounted wave-ice interaction processes, including the floe over wash.