A method to estimate reflection and directional spread using rotary spectra from accelerometers on large ice floes

Abstract

he directional wave spectra in sea ice are an important aspect of the wave evolution and can provide insights into the dominant components of wave dissipation, i.e. dissipation due to scattering or dissipation due to viscous processes under the ice. In this paper we propose a robust method for the measurement of directional wave spectra parameters in sea ice from a 3-axis accelerometer or a heave, pitch and roll sensor. Our method takes advantage of certain aspects of sea ice and makes use of rotary spectra techniques to provide model-free estimates for the mean wave direction, directional spread and reflection coefficient. The method is ideally suited for large ice floes, i.e. where the ice floe length scale is much greater than the wavelength, but a framework is provided to expand the parameter space where the method may be effective.