Ambient noise properties in a region of Puget Sound.

Abstract

Ambient noise data collected during August 2007 at a site near the Smith Island Marine Sanctuary in North Puget Sound, Washington, depth 100 m, is discussed. This marine sanctuary is representative of a marine mammal habitat, where adverse impacts of noise are of concern. Properties of the ambient noise environment are inspected relating to frequency content and vertical directionality. Wind speed and wave spectral data for correlations were provided by the Smith Island weather station and a nearby NOAA buoy. Two co‐located systems were used to estimate spectral levels of the ambient noise environment. The directional information is provided by one of these systems consisting of a pair of omni‐directional elements vertically separated by 15 cm. Candidate models for noise directionality are tested against the array gain for this simple system evaluated as a function of frequency, giving an approximate picture of the noise density as a function of vertical arrival angle at particular frequencies of interest. [Research supported by Washington Sea Grant.]