Observations of wave dispersion and attenuation in landfast ice

Abstract

Observations of wave propagation in landfast ice were obtained in Tempelfjorden, Svalbard during March 2015. Wave motion was measured near the ice edge using inertial motion units and consisted of a combination of swell from the North Atlantic and wind-generated waves. The waves were observed to be unidirectional in the ice with comparable magnitudes in the vertical and horizontal displacements. The dispersion relation was calculated from the measured phase difference between two adjacent sensors separated by a distance of approximately 60 m. Deviations from the gravity wave dispersion relation were observed during the growth phase of the waves and were consistent with the presence of flexural waves. This period of wave growth was accompanied by significant wave attenuation in the high frequency portion of the wave spectrum which persisted for 3-5 h.