An under-ice Arctic geophysical exploration sonar system concept to resolve international territorial claims.

A consequence of the shrinking polar ice cap is the increased interest in commercial shipping. Therefore, several nations are surveying the continental slopes and Arctic basin to better define the political boundaries. Under Article 76 of the United Nations Convention on the Law of the Sea (UNCLOS), the boundary between territorial and international waters is defined where the sub-bottom basement extends one kilometer from the seafloor. Therefore, icebreakers and air guns are currently implemented for deep sub-bottom profiling. However, there still remains older and thicker ice that leads to inaccessible areas for geophysical surveys from surface ships. Submarines can easily navigate below the Arctic ice, but a safer sound source must be identified to avoid air guns or explosives. An analytic formulation was developed to predict the maximum basement detection depth of an under-ice sound source. This formulation was implemented to compare candidate underwater transducers and impulsive sound sources. Results from this study will be presented with discussions on additional constraints affecting the selection process. A workable submarine system for defining territorial boundaries would also help increase our understanding of the Arctic environment and facilitate exploration for potential natural resources. Funding provided via UAF sub-award under NOAA Grant NA09NOS4000262.