The effect of ice on long range underwater sound propagation

A study has been made of the effect of ice cover on long range 100 n miles) acoustic propagation at low frequencies in an area having an approximate constant water depth of 30 fathoms. Explosive charges weighing 1.8 lb dropped from an aircraft were used as acoustic sources and the acoustic pulses were detected on a bottomed barium titanate hydrophone. Comparative measurements have been made with identical water velocity structures with no ice and with a variety of different ice conditions. Large variations of attenuation have been observed depending upon the type of ice prevalent in the area.