The development of an acoustic sensor system to measure first year sea ice thickness

This thesis reports on the development of an acoustic sea ice thickness measurement sensor which has been completed in the Autonomous Ocean System Laboratory (AOSL) of Memorial University (MUN). The development applies acoustic Non- Destructive-Testing (NDT) techniques to test first year sea ice including significant amounts of enclosed impurities (air bubbles and brine pockets). Several single piezoelectric transducers are placed tightly together on a smooth sea ice surface to emit and receive acoustic signals. In addition to showing a detectable reflection from the ice-water interface, the received signal also shows significant energy being reflected\ud from entrained impurities. Based on an assumption of randomly distributed bubbles, the desired reflection from the sea ice-seawater interface can be extracted through sampling the sea-ice in multiple locations. Based on sufficient experimental results, this method has been demonstrated to be feasible and reliable in the lab environment