Modeling and characterizing the typical under-ice acoustic channel for the Arctic

In this paper,properties of arctic underwater acoustic channel using Burke-Twersky(BT) model and ray theory was reserached.In the BT model sea ice ridge is assumed as a set of elliptical semi-cylinder randomly distributed on a stress-free surface based on BT model which is usually used to describe ice-sea surface in polar region.By approximation of low frequency and high frequency of BT model,the reflection coefficients were calculated at different frequencies.On the basis of ray theory,we calculate the acoustic field and analyze the properties of underwater acoustic channel.Compared to underwater acoustic channel properties when the boundary is air,the result shows that under the ice surface some sound rays disappear during transmission,because the ice surface reflection coefficients are smaller than absolutely soft surface.Especially under-ice transmission loss is higher when the frequency is higher.As a result,underice condition is not beneficial for acoustic signals to travel far.Under the ice surface,the multi-path structure of the channel is not significant compared to air surface.The research results are valuable for predicting performance of sonar system working in the polar region.