A study of reflection and refraction of waves at the interface of water and porous sea ice

Abstract

Sea ice is modeled as a transversely isotropic brine-saturated porous medium in accordance with the model proposed by Schwarz and Weeks [J. Glaciol. 19, 499–531 (1977)]. The reflection and refraction of waves at the water–ice interface are studied. Numerical results indicate that the porosity of the ice has a noticeable effect on the wave reflectivity. Its effect, however, becomes small when the grazing angle of the incident wave becomes small. The existence of a thin and porous ice skeleton layer on the ice medium further reduces the reflectivity. The reduction of reflectivity becomes more distinct as the frequency of the incident wave increases. Numerical results point out that, in addition to the porosity, the ice layer thickness is the most dominant property influencing the under-ice wave reflectivity. The calculated results show a qualitative agreement with the in situ experimental results by Yang and Votaw [J. Acoust. Soc. Am. 70, 841–851 (1981)].