Environmental correlate to underwater acoustic noise in the Arctic Ocean

Abstract

In an effort to find a physical parameter to use as a predictor of acoustic noise in the Arctic Ocean, a modified version of the AIDJEX plastic ice model was used to study the mechanical energy balance of the sea ice cover in the vicinity of long-term acoustic measurements taken in the Lincoln Sea in 1989–90. It was assumed that pa−pw (the rate at which the air works on the ice minus the rate at which the ice works on the water) was the power available for generating noise and that a fixed fraction of this power was converted locally into acoustic noise intensity in the water. The dominant environmental variable in this term was the geostrophic wind velocity, derived from barometric pressure measurements from The Coordinated Arctic Buoy Program [Colony and Rigor, APL/Washington]. A relative noise intensity was determined by calculating the quantity pa−pw on a grid over the Arctic Ocean, weighting by transmission loss from the grid points to the measurement site, and summing. Monthly time series correlation coefficients between pa−pw and 15-Hz noise intensity were generally near 0.6. [Sponsored by the AEAS Program of the Office of Naval Research.]