A modal analysis of acoustic propagation in the changing Arctic environment

Abstract

This work takes an in depth look at acoustic propagation through double duct sound speed profiles in the Arctic. While the traditional Arctic sound speed profile has a single surface duct, some portions of the Arctic have a sound speed profile which includes a second, lower duct. These double duct systems are seen through out the Beaufort Sea, dating back to 2004, in data made available by the Ice-Tethered Profiler program at the Woods Hole Oceanographic Institutes. The acoustic propagation through the double duct system is analyzed using normal mode analysis, through the Kraken normal mode code. A simulated lower duct is introduced in order to isolate only those modes which travel within the lower duct. Propagation through the lower duct is compared to propagation in traditional Arctic sound speed profiles, and for certain ducts distinct increases in propagation strength are shown.