A two layer model for wave dissipation in sea ice

TL;DR

This paper introduces a two-layer model for wave dissipation in sea ice, using a self-similarity scaling law and dimensional analysis to derive a viscosity equation, effectively capturing complex ice properties and matching observations.

Contribution

It proposes a novel two-layer wave dissipation model for sea ice based on self-similarity and dimensional analysis, improving parameterization in operational models.

Findings

Model's dissipation rate aligns with field and laboratory data.

Derived viscosity proportional to wave frequency and ice thickness squared.

Two-layer structure captures partial pressure gradient effects.

Abstract

Sea ice is highly complex due to the inhomogeneity of the physical properties (e.g. temperature and salinity) as well as the permeability and mixture of water and a matrix of sea ice and/or sea ice crystals. Such complexity has proven itself to be difficult to parameterize in operational wave models. Instead, we assume that there exists a self-similarity scaling law which captures the first order properties. Using dimensional analysis, an equation for the kinematic viscosity is derived which is proportional to the wave frequency and the ice thickness squared. In addition, the model allows for a two-layer structure where the oscillating pressure gradient due to wave propagation only exists in a fraction of the total ice thickness. These two assumptions lead to a spatial dissipation rate that is a function of ice thickness and wavenumber. The derived dissipation rate compares favourably with available field and laboratory observations.