Reflection of sound waves from the underside of rough ice canopy in the Arctic Ocean

Deployed instruments in the Arctic Ocean cannot easily communicate to surface or between other instruments (rigs, gliders) without using acoustics. Propagation of sound in arctic waters is therefore of paramount importance for oceanographic investigations, and a lot of effort has been directed towards such issues. The present report is inspired by observations on acoustic communication performed under the project «UNDERICE» in 2013. The purpose here is to investigate the influence of the ice sheet on the acoustic propagation, using the ray model BELLHOP as a simulation tool. The report consists of a brief description of the acoustic environment relevant for the experiment, computation of the reflection coefficient from a plane ice sheet, and 3 different approaches to model the rough underside of the ice canopy.NERSC Technical Report no. 37